Plants

21 pages, 789 KiB

Open AccessArticle

Isolation and Screening of Extracellular PGPR from the Rhizosphere of Tomato Plants after Long-Term Reduced Tillage and Cover Crops

by Maria Chiara Guerrieri, Elisabetta Fanfoni, Andrea Fiorini, Marco Trevisan and Edoardo Puglisi

Plants 2020, 9(5), 668; https://doi.org/10.3390/plants9050668 - 25 May 2020

Cited by 27 | Viewed by 7194

Abstract

Plant growth promoting rhizobacteria provide an innovative solution to address challenges in sustainable agro-ecosystems, improving plant growth as well as acting as agents of biocontrol. In this study autochthonous bacteria were isolated from the rhizosphere of processing tomato plants (Solanum lycopersicum L.) [...] Read more.

Plant growth promoting rhizobacteria provide an innovative solution to address challenges in sustainable agro-ecosystems, improving plant growth as well as acting as agents of biocontrol. In this study autochthonous bacteria were isolated from the rhizosphere of processing tomato plants (Solanum lycopersicum L.) cultivated with conservation agriculture practices (i.e., reduced tillage and cover crops), and evaluated for both growth-promoting activities (PGPAs), and antagonistic potential against the phytopathogenic pest Sclerotinia sclerotiorum. Considering the several activities of PGPR, we decided to structure the screening with a hierarchic approach, starting from testing the capability of fixing nitrogen. The obtained bacteria were processed through the molecular typing technique rep-PCR (Repetitive Extragenic Palindromic) in order to discriminate microbial strains with the same profiles, and identified via 16S rDNA sequencing. Thirty-eight selected isolates were screened in vitro for different activities related to plant nutrition and plant growth regulation as well as for antifungal traits. Isolated bacteria were found to exhibit different efficiencies in indoleacetic acid production and siderophore production, phosphate solubilization and biocontrol activity against the widespread soil-borne plant pathogen S. sclerotiorum. All the 38 bacterial isolates showed at least one property tested. With a view to detect the suitable candidates to be developed as biofertilizers, the selected isolates were ranked by their potential ability to function as PGPR. Thus, consortium of native PGPR bacteria inoculants may represent a suitable solution to address the challenges in sustainable agriculture, to ensure crop yield and quality, lowering the application of chemicals input. Full article

(This article belongs to the Special Issue Selected Plant-Related Papers from the First Joint Meeting on Soil and Plant System Sciences (SPSS 2019) “Natural and Human-induced Impacts on the Critical Zone and Food Production”)

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17 pages, 304 KiB

Open AccessEditor’s ChoiceReview

Plant Viruses Infecting Solanaceae Family Members in the Cultivated and Wild Environments: A Review

by Richard Hančinský, Daniel Mihálik, Michaela Mrkvová, Thierry Candresse and Miroslav Glasa

Plants 2020, 9(5), 667; https://doi.org/10.3390/plants9050667 - 25 May 2020

Cited by 44 | Viewed by 7838

Abstract

Plant viruses infecting crop species are causing long-lasting economic losses and are endangering food security worldwide. Ongoing events, such as climate change, changes in agricultural practices, globalization of markets or changes in plant virus vector populations, are affecting plant virus life cycles. Because [...] Read more.

Plant viruses infecting crop species are causing long-lasting economic losses and are endangering food security worldwide. Ongoing events, such as climate change, changes in agricultural practices, globalization of markets or changes in plant virus vector populations, are affecting plant virus life cycles. Because farmer’s fields are part of the larger environment, the role of wild plant species in plant virus life cycles can provide information about underlying processes during virus transmission and spread. This review focuses on the Solanaceae family, which contains thousands of species growing all around the world, including crop species, wild flora and model plants for genetic research. In a first part, we analyze various viruses infecting Solanaceae plants across the agro-ecological interface, emphasizing the important role of virus interactions between the cultivated and wild zones as global changes affect these environments on both local and global scales. To cope with these changes, it is necessary to adjust prophylactic protection measures and diagnostic methods. As illustrated in the second part, a complex virus research at the landscape level is necessary to obtain relevant data, which could be overwhelming. Based on evidence from previous studies we conclude that Solanaceae plant communities can be targeted to address complete life cycles of viruses with different life strategies within the agro-ecological interface. Data obtained from such research could then be used to improve plant protection methods by taking into consideration environmental factors that are impacting the life cycles of plant viruses. Full article

(This article belongs to the Special Issue Plant Virus Epidemiology)

13 pages, 4114 KiB

Open AccessArticle

Identification and Molecular Characterization of Geranyl Diphosphate Synthase (GPPS) Genes in Wintersweet Flower

by Hafiz Muhammad Kamran, Syed Bilal Hussain, Shang Junzhong, Lin Xiang and Long-Qing Chen

Plants 2020, 9(5), 666; https://doi.org/10.3390/plants9050666 - 24 May 2020

Cited by 12 | Viewed by 4010

Abstract

Geranyl diphosphate synthase (GPPS) is a plastid localized enzyme that catalyzes the biosynthesis of Geranyl diphosphate (GPP), which is a universal precursor of monoterpenes. Wintersweet (Chimonanthus praecox L.), a famous deciduous flowering shrub with a strong floral scent character, could have GPPS-like [...] Read more.

Geranyl diphosphate synthase (GPPS) is a plastid localized enzyme that catalyzes the biosynthesis of Geranyl diphosphate (GPP), which is a universal precursor of monoterpenes. Wintersweet (Chimonanthus praecox L.), a famous deciduous flowering shrub with a strong floral scent character, could have GPPS-like homologs that are involved in monoterpenes biosynthesis, but it remains unclear. In the present study, five full-length GPPS and geranylgeranyl diphosphate synthases (GGPPS) genes were identified in the wintersweet transcriptome database. The isolated cDNAs showed high protein sequence similarity with the other plants GPPS and GGPPS. The phylogenetic analysis further classified these cDNAs into four distinct clades, representing heterodimeric GPPS small subunits (SSU1 and SSU2), homodimeric GPPS, and GGPPS. Analysis of temporal expression revealed that all genes have the highest transcript level at the full-open flower stage. From tissue-specific expression analysis, CpGPPS.SSU1 and CpGGPPS1 were predominantly expressed in petal and flower, whereas CpGPPS.SSU2, GPPS, and GGPPS2 showed a constitutive expression. Additionally, the subcellular localization assay identified the chloroplast localization of SSUs and GGPPSs proteins, and the yeast two-hybrid assay showed that both CpGPPS.SSU1 and CpGPPS.SSU2 can interact with the GGPPS proteins. Taken together, these preliminary results suggest that the heterodimeric GPPS can regulate floral scent biosynthesis in wintersweet flower. Full article

(This article belongs to the Special Issue Biosynthesis and Functions of Terpenoids in Plants)

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10 pages, 2354 KiB

Open AccessProtocol

Development and Optimization of a Germination Assay and Long-Term Storage for Cannabis sativa Pollen

by Daniel Gaudet, Narendra Singh Yadav, Aleksei Sorokin, Andriy Bilichak and Igor Kovalchuk

Plants 2020, 9(5), 665; https://doi.org/10.3390/plants9050665 - 23 May 2020

Cited by 13 | Viewed by 7056

Abstract

Pollen viability and storage is of great interest to cannabis breeders and researchers to maintain desirable germplasm for future use in breeding or for biotechnological and gene editing applications. Here, we report a simple and efficient cryopreservation method for long-term storage of Cannabis [...] Read more.

Pollen viability and storage is of great interest to cannabis breeders and researchers to maintain desirable germplasm for future use in breeding or for biotechnological and gene editing applications. Here, we report a simple and efficient cryopreservation method for long-term storage of Cannabis sativa pollen. Additionally, the bicellular nature of cannabis pollen was identified using DAPI (4′,6-diamidino-2-phenylindole) staining. A pollen germination assay was developed to assess cannabis pollen viability and used to demonstrate that pollen collected from different principal growth stages exhibited differential longevity. Finally, a simple and efficient method that employs pollen combined with baked whole wheat flour and subsequent desiccation under vacuum was developed for the long-term cryopreservation of C. sativa pollen. Using this method, pollen viability was maintained in liquid nitrogen after four months, suggesting long-term preservation of cannabis pollen. Full article

(This article belongs to the Special Issue Pollen and Pollination)

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17 pages, 5076 KiB

Open AccessArticle

Characterization of Atypical Protein Tyrosine Kinase (PTK) Genes and Their Role in Abiotic Stress Response in Rice

by Allimuthu Elangovan, Monika Dalal, Gopinathan Kumar Krishna, Sellathdurai Devika, Ranjeet Ranjan Kumar, Lekshmy Sathee and Viswanathan Chinnusamy

Plants 2020, 9(5), 664; https://doi.org/10.3390/plants9050664 - 23 May 2020

Cited by 7 | Viewed by 3758

Abstract

Tyrosine phosphorylation constitutes up to 5% of the total phophoproteome. However, only limited studies are available on protein tyrosine kinases (PTKs) that catalyze protein tyrosine phosphorylation in plants. In this study, domain analysis of the 27 annotated PTK genes in rice genome led [...] Read more.

Tyrosine phosphorylation constitutes up to 5% of the total phophoproteome. However, only limited studies are available on protein tyrosine kinases (PTKs) that catalyze protein tyrosine phosphorylation in plants. In this study, domain analysis of the 27 annotated PTK genes in rice genome led to the identification of 18 PTKs with tyrosine kinase domain. The kinase domain of rice PTKs shared high homology with that of dual specificity kinase BRASSINOSTEROID-INSENSITIVE 1 (BRI1) of Arabidopsis. In phylogenetic analysis, rice PTKs clustered with receptor-like cytoplasmic kinases-VII (RLCKs-VII) of Arabidopsis. mRNAseq analysis using Genevestigator revealed that rice PTKs except PTK9 and PTK16 express at moderate to high level in most tissues. PTK16 expression was highly abundant in panicle at flowering stage. mRNAseq data analysis led to the identification of drought, heat, salt, and submergence stress regulated PTK genes in rice. PTK14 was upregulated under all stresses. qRT-PCR analysis also showed that all PTKs except PTK10 were significantly upregulated in root under osmotic stress. Tissue specificity and abiotic stress mediated differential regulation of PTKs suggest their potential role in development and stress response of rice. The candidate dual specificity PTKs identified in this study paves way for molecular analysis of tyrosine phosphorylation in rice. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

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14 pages, 1795 KiB

Open AccessArticle

Normal Cyclic Variation in CO₂ Concentration in Indoor Chambers Decreases Leaf Gas Exchange and Plant Growth

by James Bunce

Plants 2020, 9(5), 663; https://doi.org/10.3390/plants9050663 - 23 May 2020

Cited by 3 | Viewed by 2777

Abstract

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO₂ concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO₂ concentration within elevated CO₂ treatments in [...] Read more.

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO₂ concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO₂ concentration within elevated CO₂ treatments in the free-air CO₂ enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO₂ concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO₂ concentration of 560 μmol mol⁻¹, with “triangular” cyclic variation with standard deviations of either 4.5 or 18.0 μmol mol⁻¹ measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO₂ concentration. Tests of rates of stomatal opening and closing with step changes in light and CO₂, and tests of responses to square-wave cycling of CO₂ were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO₂ during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO₂. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO₂ conditions. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

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23 pages, 4316 KiB

Open AccessArticle

Structural Adaptation and Physiological Mechanisms in the Leaves of Anthyllis vulneraria L. from Metallicolous and Non-Metallicolous Populations

by Marzena Sujkowska-Rybkowska, Ewa Muszyńska and Mateusz Labudda

Plants 2020, 9(5), 662; https://doi.org/10.3390/plants9050662 - 23 May 2020

Cited by 10 | Viewed by 3022

Abstract

Calamine wastes highly contaminated with trace metals (TMs) are spontaneously inhabited by a legume plant Anthyllis vulneraria L. This study determined an adaptation strategy of metallicolous (M) A. vulneraria and compared it with that of the non-metallicolous (NM) ecotype. We hypothesized that TMs [...] Read more.

Calamine wastes highly contaminated with trace metals (TMs) are spontaneously inhabited by a legume plant Anthyllis vulneraria L. This study determined an adaptation strategy of metallicolous (M) A. vulneraria and compared it with that of the non-metallicolous (NM) ecotype. We hypothesized that TMs may lead to (i) leaf apoplast modifications and (ii) changes in the antioxidant machinery efficiency that facilitate plant growth under severe contamination. To verify our hypothesis, we implemented immunolabelling, transmission electron microscopy and biochemical measurements. NM leaves were larger and thicker compared to the M ecotype. Microscopic analysis of M leaves showed a lack of dysfunctions in mesophyll cells exposed to TMs. However, changes in apoplast composition and thickening of the mesophyll and epidermal cell walls in these plants were observed. Thick walls were abundant in xyloglucan, pectins, arabinan, arabinogalactan protein and extensin. The tested ecotypes differed also in their physiological responses. The metallicolous ecotype featured greater accumulation of photosynthetic pigments, enhanced activity of superoxide dismutase and increased content of specific phenol groups in comparison with the NM one. Despite this, radical scavenging activity at the level of 20% was similar in M and NM ecotypes, which may implicate effective reduction of oxidative stress in M plants. In summary, our results confirmed hypotheses and suggest that TMs induced cell wall modifications of leaves, which may play a role in metal stress avoidance in Anthyllis species. However, when TMs reach the protoplast, activation of antioxidant machinery may significantly strengthen the status of plants naturally growing in TM-polluted environment. Full article

(This article belongs to the Special Issue Heavy Metal Stress in Plants)

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20 pages, 1331 KiB

Open AccessArticle

Effects of Water Regime, Genotype, and Formative Stages on the Agro-Physiological Response of Sugarcane (Saccharum officinarum L.) to Drought

by Jose Arnel O. Reyes, Arvin S. Carpentero, Primitivo Jose A. Santos and Evelyn F. Delfin

Plants 2020, 9(5), 661; https://doi.org/10.3390/plants9050661 - 23 May 2020

Cited by 11 | Viewed by 3953

Abstract

Drought during the formative stages of a plant’s growth triggers a sequence of responses to maintain optimal growing conditions, but often at the expense of crop productivity. Two field experiments were conducted to determine the effect of drought on 10 high-yielding sugarcane genotypes [...] Read more.

Drought during the formative stages of a plant’s growth triggers a sequence of responses to maintain optimal growing conditions, but often at the expense of crop productivity. Two field experiments were conducted to determine the effect of drought on 10 high-yielding sugarcane genotypes at two formative stages (the tillering stage (TS) and stalk elongation (SS)), within 30 days after treatment imposition. The experiments followed a split-plot in a randomized complete block design with three replicates per genotype. Agro-physiological responses to drought were observed to compare the differences in the response of sugarcane during the two formative stages. Drought significantly reduced total chlorophyll content (Chl) and stomatal conductance (Gs) for both formative stages, while significantly increasing total scavenging activity (AOA) and electrolyte leakage (EC). A higher level of Chl was observed in the stalk elongation stage compared to the tillering stage; however, lower AOA coupled with higher EC in the stalk elongation stage suggests higher drought susceptibility. Pearson's correlation analysis revealed a stronger correlation between plant height, internode length, Chl, AOA, EC, and Gs at the tillering stage relative to the stalk elongation stage. Moreover, results from the multivariate analysis indicate the different contribution values of each parameter, supplementing the hypothesized difference in response between the two formative stages. Multivariate analysis clustered the 10 genotypes into groups based on the traits evaluated, suggesting the ability of these traits to detect differences in a sample population. The observed relationship among traits during the two formative stages of sugarcane will be significant in screening and identifying drought-susceptible and drought-tolerant genotypes for variety development studies. Full article

(This article belongs to the Special Issue Plant Responses to Water-Deficit Stress)

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12 pages, 835 KiB

Open AccessArticle

A Study on the Effect of Macro- and Micro- Nutrients on Nannochloropsis oceanica Growth, Fatty Acid Composition and Magnetic Harvesting Efficiency

by Maria G. Savvidou, Elenitsa Boli, Dimitrios Logothetis, Theopisti Lymperopoulou, Angelo Ferraro, Vasiliki Louli, Diomi Mamma, Dimitris Kekos, Kostis Magoulas and Fragiskos N. Kolisis

Plants 2020, 9(5), 660; https://doi.org/10.3390/plants9050660 - 23 May 2020

Cited by 13 | Viewed by 3298

Abstract

The effect of iron, manganese, phosphorus and nitrogen on growth and lipid synthesis of the microalgae Nannochloropsis oceanica CCMP1779, as well as their impact on the magnetic harvesting efficiency, are examined under their depriving cell culture conditions. Herein, it is demonstrated that nitrogen [...] Read more.

The effect of iron, manganese, phosphorus and nitrogen on growth and lipid synthesis of the microalgae Nannochloropsis oceanica CCMP1779, as well as their impact on the magnetic harvesting efficiency, are examined under their depriving cell culture conditions. Herein, it is demonstrated that nitrogen and manganese depletion primarily reduced cell growth while phosphorus and iron restriction led to higher dry biomass. Subsequently, the role of those nutrients on fatty acids profile was examined. Phosphorus and nitrogen restriction resulted in lower and higher lipid content, respectively. High amounts of polyunsaturated fatty acids like eicosapentaenoic acid are produced under iron and manganese depletion. Phosphorus deprivation favors monounsaturated fatty acids such as C18:1 and C16:1, while nitrogen restriction favors saturated fatty acid production like C14:0, C16:0 and C18:0. Since the presence/absence of macro- and micro-elements may affect the overall electrostatic charges on the outmost microalgae surface, it was also analyzed how these elements affect the magnetic harvesting efficiency. Results showed that phosphorus deprivation led to the best magnetic harvesting efficiency of N. oceanica cells (93%) as compared to other nutrient starvation as well as standard medium. Full article

(This article belongs to the Special Issue Cyanobacteria and Microalgae Biotechnologies)

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19 pages, 3815 KiB

Open AccessArticle

Designing a Clean Label Fish Patty with Olive, Citric, Pomegranate, or Rosemary Extracts

by Lorena Martínez-Zamora, Gaspar Ros and Gema Nieto

Plants 2020, 9(5), 659; https://doi.org/10.3390/plants9050659 - 22 May 2020

Cited by 14 | Viewed by 4101

Abstract

The natural functional ingredients derived from pomegranate (41.4% punicalagin), rosemary (5.8% carnosic acid and carnosol), hydroxytyrosol (7.3%), and citrus (55% hesperidin) fruits were combined separately with acerola (17% vitamin C) and essential oils rich in fatty acids (45% α-linolenic (ALA) and 40% docosahexaenoic [...] Read more.

The natural functional ingredients derived from pomegranate (41.4% punicalagin), rosemary (5.8% carnosic acid and carnosol), hydroxytyrosol (7.3%), and citrus (55% hesperidin) fruits were combined separately with acerola (17% vitamin C) and essential oils rich in fatty acids (45% α-linolenic (ALA) and 40% docosahexaenoic (DHA)) provide a natural substitute of synthetic preservatives for fish patties, avoiding E-numbers on labels. Microbiological and physicochemical properties of the formulations were examined, sensory analysis was conducted, and changes in their shelf life due to storage for 14 days under chilled storage, adding these ingredients, were determined. The results obtained showed that the fish patties reported a high level of protein (14%), low fat (<2%), with a high contribution of phosphorus and selenium minerals, and higher levels of ALA up to 40% (in the case of rosemary extract (R)) and DHA by 30% (Ct), compared to the Control sample. The fish patties suffered microbiological, flavor, and odor spoilage and rapid lipid oxidation associated with rancidity. It can be said that the fish preparations have a duration of less than 7 days (between 4–6 days), except for the preparation with pomegranate extract (P) that has a longer life, from 7 to 11 days. Consequently, replacing synthetic additives by natural extracts offers a new clean label product with potential health benefits that resembles the commercial fish patties. Full article

(This article belongs to the Special Issue Natural Products from Plant-Derived as Preservatives)

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9 pages, 860 KiB

Open AccessArticle

Investigation of Indigenous Arbuscular Mycorrhizal Performance Using a Lotus japonicus Mycorrhizal Mutant

by Taisuke Teranishi and Yoshihro Kobae

Plants 2020, 9(5), 658; https://doi.org/10.3390/plants9050658 - 22 May 2020

Cited by 3 | Viewed by 2547

Abstract

Most plants are usually colonized with arbuscular mycorrhiza fungi (AMF) in the fields. AMF absorb mineral nutrients, especially phosphate, from the soil and transfer them to the host plants. Inoculation with exotic AMF is thought to be effective when indigenous AMF performance is [...] Read more.

Most plants are usually colonized with arbuscular mycorrhiza fungi (AMF) in the fields. AMF absorb mineral nutrients, especially phosphate, from the soil and transfer them to the host plants. Inoculation with exotic AMF is thought to be effective when indigenous AMF performance is low; however, there is no method for evaluating the performance of indigenous AMF. In this study, we developed a method to investigate the performance of indigenous AMF in promoting plant growth. As Lotus japonicus mutant (str) that are unable to form functional mycorrhizal roots were considered to be symbiosis negative for indigenous mycorrhizal performance, we examined the growth ratios of wild-type and str mycorrhizal mutant using 24 soils. Each soil had its own unique indigenous mycorrhizal performance, which was not directly related to the colonization level of indigenous AMF or soil phosphate level. The low indigenous mycorrhizal performance could not be compensated by the inoculation of exotic AMF. Importantly, indigenous mycorrhizal performance was never negative; however, the inoculation of exotic AMF into the same soil led to both positive and negative performances. These results suggest that indigenous mycorrhizal performance is affected by soil management history and is basically harmless to the plant. Full article

(This article belongs to the Section Plant Nutrition)

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27 pages, 2305 KiB

Open AccessArticle

Phytoremediation Potential, Photosynthetic and Antioxidant Response to Arsenic-Induced Stress of Dactylis glomerata L. Sown on Fly Ash Deposits

by Gordana Gajić, Lola Djurdjević, Olga Kostić, Snežana Jarić, Branka Stevanović, Miroslava Mitrović and Pavle Pavlović

Plants 2020, 9(5), 657; https://doi.org/10.3390/plants9050657 - 22 May 2020

Cited by 23 | Viewed by 3371

Abstract

Arsenic (As) from coal fly ash can be released into soil/groundwater, presenting a global threat to the environment and human health. To overcome this environmental problem, phytoremediation represents an urgent need, providing ‘green’ cleanup of contaminated lands. The present study focused on As [...] Read more.

Arsenic (As) from coal fly ash can be released into soil/groundwater, presenting a global threat to the environment and human health. To overcome this environmental problem, phytoremediation represents an urgent need, providing ‘green’ cleanup of contaminated lands. The present study focused on As concentrations in fly ash and plants, evaluation of phytoremediation potential of Dactylis glomerata sown on fly ash deposits together with its photosynthetic activity, and oxidative and antioxidative response to As stress. Field research was carried out on fly ash deposits at the thermal power plant “Nikola Tesla”, Obrenovac (TENT-A, Serbia) and the control site. Fly ash is characterized by alkaline pH reactions, small amounts of organic matter, a large amount of available phosphate, and total and available As concentrations. Results in this study indicate that phosphate application can ameliorate As toxicity, uptake and root-shoot transport. Furthermore, D. glomerata can be considered as good As phytostabilizator, because it retains more As in roots than in leaves. Excess As in leaves decreases photosynthetic efficiency (Fv/Fm) and concentrations of chlorophylls, carotenoids, and anthocyanins, whereas high content of malondialdehyde (MDA) can be a signal for biosynthesis phenolics and ascorbic acid, providing cellular redox homeostasis and recovery of photosystem II (PSII) photochemistry. In the roots, low oxidative stress under high concentrations of As is related to intense antioxidant biosynthesis. Taken together, the results in this study indicate a high adaptive potential of D. glomerata to As stress. These findings may suggest that physiological and metabolic tools can be used as a way forward in the ‘real field’ scenario, phytomanagement of fly ash and ecosystem services providing sustainable phytoremediation of As-contaminated sites around the globe. Full article

(This article belongs to the Special Issue Fundamental and Applied Research for the Effective Deployment of Phytoremediation)

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15 pages, 1434 KiB

Open AccessArticle

Micropropagation, Genetic Fidelity and Phenolic Compound Production of Rheum rhabarbarum L.

by Doina Clapa, Orsolya Borsai, Monica Hârța, Victoriţa Bonta, Katalin Szabo, Vasile Coman and Otilia Bobiș

Plants 2020, 9(5), 656; https://doi.org/10.3390/plants9050656 - 22 May 2020

Cited by 12 | Viewed by 3797

Abstract

An efficient micropropagation protocol for Rheum rhabarbarum L. was developed in this study. The in vitro rhubarb plants obtained in the multiplication stage (proliferation rate: 5.0 ± 0.5) were rooted in vitro (96% rooting percentage) and acclimatized ex vitro in floating perlite, with [...] Read more.

An efficient micropropagation protocol for Rheum rhabarbarum L. was developed in this study. The in vitro rhubarb plants obtained in the multiplication stage (proliferation rate: 5.0 ± 0.5) were rooted in vitro (96% rooting percentage) and acclimatized ex vitro in floating perlite, with 90% acclimatization percentage. To assess the genetic fidelity between the mother plant and in vitro propagated plants, sequence-related amplified polymorphism (SRAP) markers were used. All banding profiles from the micropropagated plants were monomorphic and similar to those of the mother plant indicating 100% similarity. Regarding the polyphenolic profile, gallic, protocatechuic, p-hydroxybenzoic, vanillic, chlorogenic, caffeic, syringic, p-coumaric and ferulic acid were present in different amounts (2.3–2690.3 μg g⁻¹ dry plant), according to the extracted matrix. Aglicons and glycosides of different classes of flavonoids were also identified. The rhizome extracts (both from in vitro and field grown plants) contained resveratrol, a stilbene compound with high antioxidant properties, ranging between 229.4 to 371.7 μg g⁻¹ plant. Our results suggest that in vitro propagation of Rheum rhabarbarum L. represents a reliable alternative to obtain a large number of true-to-type planting material with high bioactive compound content of this valuable nutritional and medicinal species. Full article

(This article belongs to the Special Issue Plant Tissue Culture)

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10 pages, 2554 KiB

Open AccessArticle

Insecticidal Activity of Hyoscyamus niger L. on Lucilia sericata Causing Myiasis

by Esra Küpeli Akkol, Mert Ilhan, Esma Kozan, Fatma Tuğçe Gürağaç Dereli, Mustafa Sak and Eduardo Sobarzo-Sánchez

Plants 2020, 9(5), 655; https://doi.org/10.3390/plants9050655 - 22 May 2020

Cited by 11 | Viewed by 4268

Abstract

Background: Hyoscyamus niger L. (Solanaceae) generally known as henbane, is commonly distributed in Europe and Asia. In Turkey, henbane seeds have been used in folk medicine to remove worms from the eyes. The present study aimed to investigate the insecticidal activity of H. [...] Read more.

Background: Hyoscyamus niger L. (Solanaceae) generally known as henbane, is commonly distributed in Europe and Asia. In Turkey, henbane seeds have been used in folk medicine to remove worms from the eyes. The present study aimed to investigate the insecticidal activity of H. niger seeds. Methods: n-hexane, ethyl acetate, methanol and alkaloid extracts were prepared from the seeds of the plant and their insecticidal activities on Lucilia sericata larvae were evaluated. EC₅₀ and EC₉₀ values of the alkaloid extract were calculated and morphological abnormalities were investigated. Results: Alkaloid extract prepared from the seeds of this plant displayed significant insecticidal activity. EC₅₀ values of H. niger seeds alkaloid extract were found to be 8.04, 8.49, 7.96 μg/mL against first, second and third instar, respectively. It was determined that malformations of larvae included damaged larvae with small size, contraction and weak cuticle. Furthermore, HPLC analysis was performed on alkaloid extract of H. niger seeds and main components of the extract were determined. It was determined that alkaloid extract mainly contain hyoscyamine and scopolamine. Conclusions: These results confirm the folkloric usage of the plant and suggest that the alkaloid content of the plant could be responsible for the insecticidal activity. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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16 pages, 3250 KiB

Open AccessArticle

Characterization of Colletotrichum ocimi Population Associated with Black Spot of Sweet Basil (Ocimum basilicum) in Northern Italy

by Santa Olga Cacciola, Giovanna Gilardi, Roberto Faedda, Leonardo Schena, Antonella Pane, Angelo Garibaldi and Maria Lodovica Gullino

Plants 2020, 9(5), 654; https://doi.org/10.3390/plants9050654 - 22 May 2020

Cited by 19 | Viewed by 5293

Abstract

Black spot is a major foliar disease of sweet basil (Ocimum basilicum) present in a typical cultivation area of northern Italy, including the Liguria and southern Piedmont regions, where this aromatic herb is an economically important crop. In this study, 15 [...] Read more.

Black spot is a major foliar disease of sweet basil (Ocimum basilicum) present in a typical cultivation area of northern Italy, including the Liguria and southern Piedmont regions, where this aromatic herb is an economically important crop. In this study, 15 Colletotrichum isolates obtained from sweet basil plants with symptoms of black spot sampled in this area were characterized morphologically and by nuclear DNA analysis using internal transcribed spacers (ITS) and intervening 5.8S nrDNA as well as part of the β-tubulin gene (TUB2) regions as barcode markers. Analysis revealed all but one isolate belonged to the recently described species C. ocimi of the C. destructivum species complex. Only one isolate was identified as C. destructivum sensu stricto (s.s.). In pathogenicity tests on sweet basil, both C. ocimi and C. destructivum s.s. isolates incited typical symptoms of black spot, showing that although C. ocimi prevails in this basil production area, it is not the sole causal agent of black spot in northern Italy. While no other hosts of C. ocimi are known worldwide, the close related species C. destructivum has a broad host range, suggesting a speciation process of C. ocimi within this species complex driven by adaptation to the host. Full article

(This article belongs to the Special Issue The Challenge of Coping with Globally and Locally Emerging Fungal and Oomycetes Plant Pathogens)

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21 pages, 4305 KiB

Open AccessArticle

MicroRNA156 (miR156) Negatively Impacts Mg-Protoporphyrin IX (Mg-Proto IX) Biosynthesis and Its Plastid-Nucleus Retrograde Signaling in Apple

by Qingbo Zheng, Yakun Chen, Xiaolin Jia, Yi Wang, Ting Wu, Xuefeng Xu, Zhenhai Han, Zhihong Zhang and Xinzhong Zhang

Plants 2020, 9(5), 653; https://doi.org/10.3390/plants9050653 - 22 May 2020

Cited by 5 | Viewed by 2748

Abstract

Plastid-nucleus retrograde signaling (PNRS) play essential roles in regulating nuclear gene expression during plant growth and development. Excessive reactive oxygen species can trigger PNRS. We previously reported that in apple (Malus domestica Borkh.) seedlings, the expression of microRNA156 (miR156) was significantly low [...] Read more.

Plastid-nucleus retrograde signaling (PNRS) play essential roles in regulating nuclear gene expression during plant growth and development. Excessive reactive oxygen species can trigger PNRS. We previously reported that in apple (Malus domestica Borkh.) seedlings, the expression of microRNA156 (miR156) was significantly low in the adult phase, which was accompanied by high levels of hydrogen peroxide (H₂O₂) accumulation in chloroplasts. However, it was unclear whether adult-phase-specific chloroplast H₂O₂ may induce PNRS and affect miR156 expression, or miR156 triggers adult phase PNRS during the ontogenesis. In this paper, we examined the relationship between miR156 levels and six PNRS components in juvenile and adult phase leaves from ‘Zisai Pearl’×‘Red Fuji’ hybrids. We found that PNRS generated by singlet oxygen (¹O₂), the photosynthetic redox state, methylerythritol cyclodiphosphate (MEcPP), SAL1-3-phosphoadenosine 5-phosphate (PAP) and WHIRLY1 were not involved. The accumulation of Mg-protoporphyrin IX (Mg-Proto IX), the expression of the synthetic genes MdGUN5 and MdGUN6, and Mg-Proto IX PNRS related nuclear genes increased with ontogenesis. These changes were negatively correlated with miR156 expression. Manipulating Mg-Proto IX synthesis with 5-aminolevulinic acid (ALA) or gabaculine did not affect miR156 expression in vitro shoots. In contrast, modulating miR156 expression via MdGGT1 or MdMIR156a6 transgenesis led to changes in Mg-Proto IX contents and the corresponding gene expressions. It was concluded that the Mg-Proto IX PNRS was regulated downstream of miR156 regardless of adult-phase-specific plastid H₂O₂ accumulation. The findings may facilitate the understanding of the mechanism of ontogenesis in higher plants. Full article

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19 pages, 4054 KiB

Open AccessArticle

Genetic Diversity, Population Structure and Marker-Trait Association for 100-Seed Weight in International Safflower Panel Using SilicoDArT Marker Information

by Fawad Ali, Muhammad Azhar Nadeem, Muzaffer Barut, Ephrem Habyarimana, Hassan Javed Chaudhary, Iftikhar Hussain Khalil, Ahmad Alsaleh, Rüştü Hatipoğlu, Tolga Karaköy, Cemal Kurt, Muhammad Aasim, Muhammad Sameeullah, Ndiko Ludidi, Seung Hwan Yang, Gyuhwa Chung and Faheem Shehzad Baloch

Plants 2020, 9(5), 652; https://doi.org/10.3390/plants9050652 - 21 May 2020

Cited by 21 | Viewed by 4365

Abstract

Safflower is an important oilseed crop mainly grown in the arid and semi-arid regions of the world. The aim of this study was to explore phenotypic and genetic diversity, population structure, and marker-trait association for 100-seed weight in 94 safflower accessions originating from [...] Read more.

Safflower is an important oilseed crop mainly grown in the arid and semi-arid regions of the world. The aim of this study was to explore phenotypic and genetic diversity, population structure, and marker-trait association for 100-seed weight in 94 safflower accessions originating from 26 countries using silicoDArT markers. Analysis of variance revealed statistically significant genotypic effects (p < 0.01), while Turkey samples resulted in higher 100-seed weight compared to Pakistan samples. A Constellation plot divided the studied germplasm into two populations on the basis of their 100-seed weight. Various mean genetic diversity parameters including observed number of alleles (1.99), effective number of alleles (1.54), Shannon’s information index (0.48), expected heterozygosity (0.32), and unbiased expected heterozygosity (0.32) for the entire population exhibited sufficient genetic diversity using 12232 silicoDArT markers. Analysis of molecular variance (AMOVA) revealed that most of the variations (91%) in world safflower panel are due to differences within country groups. A model-based structure grouped the 94 safflower accessions into populations A, B, C and an admixture population upon membership coefficient. Neighbor joining analysis grouped the safflower accessions into two populations (A and B). Principal coordinate analysis (PCoA) also clustered the safflower accessions on the basis of geographical origin. Three accessions; Egypt-5, Egypt-2, and India-2 revealed the highest genetic distance and hence might be recommended as candidate parental lines for safflower breeding programs. The mixed linear model i.e., the Q + K model, demonstrated that two DArTseq markers (DArT-45483051 and DArT-15672391) had significant association (p < 0.01) for 100-seed weight. We envisage that identified DArTseq markers associated with 100-seed weight will be helpful to develop high-yielding cultivars of safflower through marker-assisted breeding in the near future. Full article

(This article belongs to the Special Issue Plant Biodiversity and Genetic Resources)

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12 pages, 599 KiB

Open AccessReview

Rosemary (Rosmarinus officinalis L., syn Salvia rosmarinus Spenn.) and Its Topical Applications: A Review

by Lucas Malvezzi de Macedo, Érica Mendes dos Santos, Lucas Militão, Louise Lacalendola Tundisi, Janaína Artem Ataide, Eliana Barbosa Souto and Priscila Gava Mazzola

Plants 2020, 9(5), 651; https://doi.org/10.3390/plants9050651 - 21 May 2020

Cited by 92 | Viewed by 27763

Abstract

Topical application is an important administration route for drugs requiring local action on the skin, thereby avoiding their systemic absorption and adverse side effects. Rosmarinus officinalis L. (syn. Salvia rosmarinus Spenn.), popularly known as rosemary, is an aromatic plant with needle-like leaves belonging [...] Read more.

Topical application is an important administration route for drugs requiring local action on the skin, thereby avoiding their systemic absorption and adverse side effects. Rosmarinus officinalis L. (syn. Salvia rosmarinus Spenn.), popularly known as rosemary, is an aromatic plant with needle-like leaves belonging to the Lamiaceae family. Rosemary has therapeutic properties and has been used in the folk medicine, pharmaceutical, and cosmetics industries, mainly for its antioxidant and anti-inflammatory properties, which are attributed to the presence of carnosol/carnosic and ursolic acids. The therapeutic use of rosemary has been explored for the treatment of inflammatory diseases; however, other uses have been studied, such as wound healing and skin cancer and mycoses treatments, among others. Besides it therapeutic uses, rosemary has potential applications in cosmetic formulations and in the treatment of pathological and non-pathological conditions, such as cellulite, alopecia, ultraviolet damage, and aging. This review aims to critically discuss the topical applications of rosemary found in the literature while also offering relevant information for the development of topical formulations of its bioactive compounds. Full article

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14 pages, 5423 KiB

Open AccessArticle

by Jianwu Li, Maoyin Li, Shuaibing Yao, Guangqin Cai and Xuemin Wang

Plants 2020, 9(5), 650; https://doi.org/10.3390/plants9050650 - 20 May 2020

Cited by 9 | Viewed by 2989

Abstract

Patatin-related phospholipases (pPLAs) are acyl-hydrolyzing enzymes implicated in various processes, including lipid metabolism, signal transduction, plant growth and stress responses, but the function for many specific pPLAs in plants remains unknown. Here we determine the effect of patatin-related phospholipase A pPLAIIIγ on Arabidopsis [...] Read more.

Patatin-related phospholipases (pPLAs) are acyl-hydrolyzing enzymes implicated in various processes, including lipid metabolism, signal transduction, plant growth and stress responses, but the function for many specific pPLAs in plants remains unknown. Here we determine the effect of patatin-related phospholipase A pPLAIIIγ on Arabidopsis response to abiotic stress. Knockout of pPLAIIIγ rendered plants more sensitive whereas overexpression of pPLAIIIγ enhanced plant tolerance to NaCl and drought in seed germination and seedling growth. The pPLAIIIγ-knockout and overexpressing seedlings displayed a lower and higher level of lysolipids and free fatty acids than that of wild-type plants in response to NaCl stress, respectively. These results indicate that pPLAIIIγ acts a positive regulator of salt and osmatic stress tolerance in Arabidopsis. Full article

(This article belongs to the Special Issue Function of Lipids in Plant Stress)

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13 pages, 2907 KiB

Open AccessArticle

Prospects of Using Termite Mound Soil Organic Amendment for Enhancing Soil Nutrition in Southern Africa

by Kafula Chisanga, Ernest R. Mbega and Patrick A. Ndakidemi

Plants 2020, 9(5), 649; https://doi.org/10.3390/plants9050649 - 20 May 2020

Cited by 14 | Viewed by 3801

Abstract

Termite mound soils are reportedly utilized as an alternative to NPK fertilizers by cash
constrained smallholder farmers in some parts of Southern Africa. However, there is limited
knowledge regarding their mineral nutritional value. The intention of this work was therefore to
investigate the [...] Read more.

Termite mound soils are reportedly utilized as an alternative to NPK fertilizers by cash
constrained smallholder farmers in some parts of Southern Africa. However, there is limited
knowledge regarding their mineral nutritional value. The intention of this work was therefore to
investigate the macro and micronutrient composition of different sections of the termite mounds;
top, base and neighboring areas. The study approach involved physical and chemical analysis of 36
sites across Pemba and Choma districts in Southern Zambia through collection of soil samples in
triplicate at 0–20 cm depth, using a soil auger. Findings revealed that the soil pH had elevated
levels in the base segments of the termite mounds compared with the top and the neighbouring
soils. However, elevated N, P and K levels were recorded in the top sections with significant
differences (P < 0.05) in clay and silt composition observed. Additionally, metallic micronutrients,
Cu and Zn were also found to be elevated in termite mounds in contrast to surrounding soils. We
concluded that top termite mound soil should be considered as part of an integrated nutrient
management strategy by financially challenged smallholder farmers cultivating in light textured
soils of southern Africa. Full article

(This article belongs to the Special Issue Soil Nutrition and Plants Growth)

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24 pages, 2832 KiB

Open AccessReview

Contributions and Limitations of Biophysical Approaches to Study of the Interactions between Amphiphilic Molecules and the Plant Plasma Membrane

by Aurélien L. Furlan, Yoann Laurin, Camille Botcazon, Nely Rodríguez-Moraga, Sonia Rippa, Magali Deleu, Laurence Lins, Catherine Sarazin and Sébastien Buchoux

Plants 2020, 9(5), 648; https://doi.org/10.3390/plants9050648 - 20 May 2020

Cited by 11 | Viewed by 4102

Abstract

Some amphiphilic molecules are able to interact with the lipid matrix of plant plasma membranes and trigger the immune response in plants. This original mode of perception is not yet fully understood and biophysical approaches could help to obtain molecular insights. In this [...] Read more.

Some amphiphilic molecules are able to interact with the lipid matrix of plant plasma membranes and trigger the immune response in plants. This original mode of perception is not yet fully understood and biophysical approaches could help to obtain molecular insights. In this review, we focus on such membrane-interacting molecules, and present biophysically grounded methods that are used and are particularly interesting in the investigation of this mode of perception. Rather than going into overly technical details, the aim of this review was to provide to readers with a plant biochemistry background a good overview of how biophysics can help to study molecular interactions between bioactive amphiphilic molecules and plant lipid membranes. In particular, we present the biomimetic membrane models typically used, solid-state nuclear magnetic resonance, molecular modeling, and fluorescence approaches, because they are especially suitable for this field of research. For each technique, we provide a brief description, a few case studies, and the inherent limitations, so non-specialists can gain a good grasp on how they could extend their toolbox and/or could apply new techniques to study amphiphilic bioactive compound and lipid interactions. Full article

(This article belongs to the Special Issue Plant Plasma Membrane)

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25 pages, 2221 KiB

Open AccessArticle

Ethnobotanical Survey of Plants Used for Treating Cough Associated with Respiratory Conditions in Ede South Local Government Area of Osun State, Nigeria

by Ibraheem Oduola Lawal, Ikeolu Idowu Olufade, Basirat Olabisi Rafiu and Adeyemi O. Aremu

Plants 2020, 9(5), 647; https://doi.org/10.3390/plants9050647 - 20 May 2020

Cited by 26 | Viewed by 6213

Abstract

In many developing countries, community members depend on their local flora for treating diverse ailments including those affecting the respiratory system. This is often attributed to the high cost and limited access to health care facilities. This present study focused on the documentation [...] Read more.

In many developing countries, community members depend on their local flora for treating diverse ailments including those affecting the respiratory system. This is often attributed to the high cost and limited access to health care facilities. This present study focused on the documentation of plant species used against cough associated with the respiratory diseases in Ede South Local Government Area of Osun State. The survey was conducted using semi-structured interviews among 100 participants. Information obtained was analyzed using different ethno-botanical indices including relative frequency of citation (RFC) and fidelity level (FL). A total of 87 plant species from 39 families, which was mostly represented by Fabaceae, were reported in the study area. Crinum jagus was the most popular plant used against cough and approximately 32% of the plants have been reported as cough remedies for the first time. However, some of the documented plants have been reported for the treatment of cough and related respiratory diseases in several countries. In terms of the life-form, trees constituted the highest proportion of the medicinal plants (37%), while leaves (36%) were the predominant plant part prescribed for cough. Decoction was the main method of preparing the plants, which were all administered orally. Approximately 63% of the plants were exclusively sourced from the wild. The current study revealed the richness and widespread use of plant species for managing cough associated with respiratory diseases in the study area. The generated inventory contributes to the expanding database of valuable plant resources with medicinal potential in Nigeria and Africa. Full article

(This article belongs to the Special Issue Insights into Ethnobotanical Research: Linking Tradition, Innovation, and Sustainability)

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17 pages, 1004 KiB

Open AccessArticle

Phytochemical Analysis and Biological Investigation of Nepeta juncea Benth. Different Extracts

by Majid Sharifi-Rad, Francesco Epifano, Serena Fiorito and José M. Álvarez-Suarez

Plants 2020, 9(5), 646; https://doi.org/10.3390/plants9050646 - 19 May 2020

Cited by 33 | Viewed by 4247

Abstract

This study was carried out to screen the amount and the classes of secondary metabolites and to evaluate the antioxidant, cytotoxic, antifungal, and antibacterial activities of the methanolic, ethanolic, and water extracts of the roots, leaves, and flowers of Nepeta juncea Benth. The [...] Read more.

This study was carried out to screen the amount and the classes of secondary metabolites and to evaluate the antioxidant, cytotoxic, antifungal, and antibacterial activities of the methanolic, ethanolic, and water extracts of the roots, leaves, and flowers of Nepeta juncea Benth. The results show that the highest total phenol (69.54 ± 0.31 mg gallic acid equivalents (GAE)/g dry weight), total flavonoid (41.37 ± 0.17 mg quercetin equivalents (QE)/g dry weight), anthocyanin (6.52 ± 0.21 mg cyanidin/100 g dry weight), and tannin (47.36 ± 0.33 mg catechin/g dry weight) concentrations were recorded in the methanolic extract of the leaves of N. juncea. The gas chromatography–mass spectrometry (GC–MS) analysis of the extracts showed that 1,8-cineole, 4aα-7α-7aα-nepetalactone, β-pinene, terpinen-4-ol, and α-terpineol were the major compounds, respectively. The best 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric-reducing antioxidant, cytotoxic, antifungal, and antibacterial activities were observed for the methanolic extract of the leaves. For the two latter activities, the best activity was revealed on Staphylococcus aureus, Bacillus cereus, and Candida albicans. The minimum inhibitory concentration (MIC) values for the antimicrobial of the methanolic extract from the leaves were in the range of 25–100 µg/mL, whereas the minimum bactericidal concentration (MBC) values were in the range of 50–200 µg/mL. The results reported herein show that, for the first time in the literature, N. juncea is a remarkable source of antioxidant, antifungal, and antibacterial compounds. Full article

(This article belongs to the Special Issue Medicinal Plants)

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22 pages, 3146 KiB

Open AccessArticle

Root Foraging Capacity in Bambara Groundnut (Vigna Subterranea (L.) Verdc.) Core Parental Lines Depends on the Root System Architecture during the Pre-Flowering Stage

by Kumbirai Ivyne Mateva, Hui Hui Chai, Sean Mayes and Festo Massawe

Plants 2020, 9(5), 645; https://doi.org/10.3390/plants9050645 - 19 May 2020

Cited by 6 | Viewed by 4157

Abstract

Characterizing the morphological variability in root system architecture (RSA) during the sensitive pre-flowering growth stage is important for crop performance. To assess this variation, eight bambara groundnut single genotypes derived from landraces of contrasting geographic origin were selected for root system architecture and [...] Read more.

Characterizing the morphological variability in root system architecture (RSA) during the sensitive pre-flowering growth stage is important for crop performance. To assess this variation, eight bambara groundnut single genotypes derived from landraces of contrasting geographic origin were selected for root system architecture and rooting distribution studies. Plants were grown in a polyvinyl chloride (PVC) column system under controlled water and nutrient availability in a rainout shelter. Days to 50% plant emergence was characterized during the first two weeks after sowing, while taproot length (TRL), root length (RL), root length density (RLD), branching number (BN), branching density (BD) and intensity (BI), surface area (SA), root volume (RV), root diameter (RDia), root dry weight (RDW), shoot dry weight (SDW), and shoot height (SH) were determined at the end of the experiment, i.e., 35 days after emergence. Genotypes S19-3 and DipC1 sourced from drier regions of sub-Saharan Africa generally had longer taproots and greater root length distribution in deeper (60 to 90 cm) soil depths. In contrast, bambara groundnut genotypes from wetter regions (i.e., Gresik, Lunt, and IITA-686) in Southeast Asia and West Africa exhibited relatively shallow and highly branched root growth closer to the soil surface. Genotypes at the pre-flowering growth stage showed differential root foraging patterns and branching habits with two extremes, i.e., deep-cheap rooting in the genotypes sourced from dry regions and a shallow-costly rooting system in genotypes adapted to higher rainfall areas with shallow soils. We propose specific bambara groundnut genotype as donors in root trait driven breeding programs to improve water capture and use efficiency. Full article

(This article belongs to the Section Plant–Soil Interactions)

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18 pages, 869 KiB

Open AccessArticle

Foliar Glycine Betaine or Hydrogen Peroxide Sprays Ameliorate Waterlogging Stress in Cape Gooseberry

by Nicolas E. Castro-Duque, Cristhian C. Chávez-Arias and Hermann Restrepo-Díaz

Plants 2020, 9(5), 644; https://doi.org/10.3390/plants9050644 - 19 May 2020

Cited by 14 | Viewed by 3312

Abstract

Exogenous glycine betaine (GB) or hydrogen peroxide (H₂O₂) application has not been explored to mitigate waterlogging stress in Andean fruit trees. The objective of this study was to evaluate foliar GB or H₂O₂ application on the [...] Read more.

Exogenous glycine betaine (GB) or hydrogen peroxide (H₂O₂) application has not been explored to mitigate waterlogging stress in Andean fruit trees. The objective of this study was to evaluate foliar GB or H₂O₂ application on the physiological behavior of Cape gooseberry plants under waterlogging. Two separate experiments were carried out. In the first trial, the treatment groups were: (1) plants without waterlogging and with no foliar applications, (2) plants with waterlogging and without foliar applications, and (3) waterlogged plants with 25, 50, or 100 mM of H₂O₂ or GB, respectively. The treatments in the second trial were: (1) plants without waterlogging and with no foliar applications, (2) plants with waterlogging and without foliar applications, and (3) waterlogged plants with 100 mM of H₂O₂ or GB, respectively. In the first experiment, plants with waterlogging and with exogenous GB or H₂O₂ applications at a dose of 100 mM showed higher leaf water potential (−0.5 Mpa), dry weight (1.0 g), and stomatal conductance (95 mmol·m⁻²·s⁻¹) values. In the second experiment, exogenously supplied GB or H₂O₂ also increased the relative growth rate, and leaf photosynthesis mitigating waterlogging stress. These results show that short-term GB or H₂O₂ supply can be a tool in managing waterlogging in Cape gooseberry. Full article

(This article belongs to the Special Issue Plant Responses to Hypoxia)

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12 pages, 7577 KiB

Open AccessEditor’s ChoiceArticle

Silicon Alters Leaf Surface Morphology and Suppresses Insect Herbivory in a Model Grass Species

by Casey R. Hall, Vaibhav Dagg, Jamie M. Waterman and Scott N. Johnson

Plants 2020, 9(5), 643; https://doi.org/10.3390/plants9050643 - 19 May 2020

Cited by 33 | Viewed by 4923

Abstract

Grasses accumulate large amounts of silicon (Si) which is deposited in trichomes, specialised silica cells and cell walls. This may increase leaf toughness and reduce cell rupture, palatability and digestion. Few studies have measured leaf mechanical traits in response to Si, thus the [...] Read more.

Grasses accumulate large amounts of silicon (Si) which is deposited in trichomes, specialised silica cells and cell walls. This may increase leaf toughness and reduce cell rupture, palatability and digestion. Few studies have measured leaf mechanical traits in response to Si, thus the effect of Si on herbivores can be difficult to disentangle from Si-induced changes in leaf surface morphology. We assessed the effects of Si on Brachypodium distachyon mechanical traits (specific leaf area (SLA), thickness, leaf dry matter content (LDMC), relative electrolyte leakage (REL)) and leaf surface morphology (macrohairs, prickle, silica and epidermal cells) and determined the effects of Si on the growth of two generalist insect herbivores (Helicoverpa armigera and Acheta domesticus). Si had no effect on leaf mechanical traits; however, Si changed leaf surface morphology: silica and prickle cells were on average 127% and 36% larger in Si supplemented plants, respectively. Prickle cell density was significantly reduced by Si, while macrohair density remained unchanged. Caterpillars were more negatively affected by Si compared to crickets, possibly due to the latter having a thicker and thus more protective gut lining. Our data show that Si acts as a direct defence against leaf-chewing insects by changing the morphology of specialised defence structures without altering leaf mechanical traits. Full article

(This article belongs to the Special Issue The Role of Silicon in Plant Defences)

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28 pages, 1465 KiB

Open AccessArticle

Phenotypic Examination of Camelina sativa (L.) Crantz Accessions from the USDA-ARS National Genetics Resource Program

by Sara K. Hotton, Meridith Kammerzell, Ron Chan, Bryan T. Hernandez, Hugh A. Young, Christian Tobias, Thomas McKeon, Jenny Brichta, Nathan J. Thomson and James G. Thomson

Plants 2020, 9(5), 642; https://doi.org/10.3390/plants9050642 - 19 May 2020

Cited by 10 | Viewed by 4243

Abstract

Camelina sativa (L.) Crntz. is a hardy self-pollinated oilseed plant that belongs to the Brassicaceae family; widely grown throughout the northern hemisphere until the 1940s for production of vegetable oil but was later displaced by higher-yielding rapeseed and sunflower crops. However, interest in [...] Read more.

Camelina sativa (L.) Crntz. is a hardy self-pollinated oilseed plant that belongs to the Brassicaceae family; widely grown throughout the northern hemisphere until the 1940s for production of vegetable oil but was later displaced by higher-yielding rapeseed and sunflower crops. However, interest in camelina as an alternative oil source has been renewed due to its high oil content that is rich in polyunsaturated fatty acids, antioxidants as well as its ability to grow on marginal lands with minimal requirements. For this reason, our group decided to screen the existing (2011) National Genetic Resources Program (NGRP) center collection of camelina for its genetic diversity and provide a phenotypic evaluation of the cultivars available. Properties evaluated include seed and oil traits, developmental and mature morphologies, as well as chromosome content. Selectable marker genes were also evaluated for potential use in biotech manipulation. Data is provided in a raw uncompiled format to allow other researchers to analyze the unbiased information for their own studies. Our evaluation has determined that the NGRP collection has a wide range of genetic potential for both breeding and biotechnological manipulation purposes. Accessions were identified within the NGRP collection that appear to have desirable seed harvest weight (5.06 g/plant) and oil content (44.1%). Other cultivars were identified as having fatty acid characteristics that may be suitable for meal and/or food use, such as low (<2%) erucic acid content, which is often considered for healthy consumption and ranged from a high of 4.79% to a low of 1.83%. Descriptive statistics are provided for a breadth of traits from 41 accessions, as well as raw data, and key seed traits are further explored. Data presented is available for public use. Full article

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16 pages, 678 KiB

Open AccessReview

The Many Questions about Mini Chromosomes in Colletotrichum spp.

by Peter-Louis Plaumann and Christian Koch

Plants 2020, 9(5), 641; https://doi.org/10.3390/plants9050641 - 19 May 2020

Cited by 5 | Viewed by 3570

Abstract

Many fungal pathogens carry accessory regions in their genome, which are not required for vegetative fitness. Often, although not always, these regions occur as relatively small chromosomes in different species. Such mini chromosomes appear to be a typical feature of many filamentous plant [...] Read more.

Many fungal pathogens carry accessory regions in their genome, which are not required for vegetative fitness. Often, although not always, these regions occur as relatively small chromosomes in different species. Such mini chromosomes appear to be a typical feature of many filamentous plant pathogens. Since these regions often carry genes coding for effectors or toxin-producing enzymes, they may be directly related to virulence of the respective pathogen. In this review, we outline the situation of small accessory chromosomes in the genus Colletotrichum, which accounts for ecologically important plant diseases. We summarize which species carry accessory chromosomes, their gene content, and chromosomal makeup. We discuss the large variation in size and number even between different isolates of the same species, their potential roles in host range, and possible mechanisms for intra- and interspecies exchange of these interesting genetic elements. Full article

(This article belongs to the Special Issue Interactions between Colletotrichum Species and Plants)

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16 pages, 994 KiB

Open AccessArticle

Are Reproductive Traits Related to Pollen Limitation in Plants? A Case Study from a Central European Meadow

by Michael Bartoš, Štěpán Janeček, Petra Janečková, Eliška Chmelová, Robert Tropek, Lars Götzenberger, Yannick Klomberg and Jana Jersáková

Plants 2020, 9(5), 640; https://doi.org/10.3390/plants9050640 - 19 May 2020

Cited by 5 | Viewed by 3668

Abstract

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Because of the ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is [...] Read more.

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Because of the ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is challenging within current ecological research. In our study we used pollen supplementation to evaluate pollen limitation (at the level of seed number and weight) in 22 plant species growing in a wet semi-natural meadow. We investigated the correlation between the pollen limitation index (PL) and floral traits associated with plant reproduction or pollinator foraging behavior. We recorded significant pollen limitation for approximately 41% of species (9 out of 22 surveyed). Seven species had a significant positive response in seed production and two species increased in seed weight after pollen supplementation. Considering traits, PL significantly decreased with the number of pollinator functional groups. The relationship of PL with other examined traits was not supported by our results. The causes of pollen limitation may vary among species with regard to (1) different reproductive strategies and life history, and/or (2) temporary changes in influence of biotic and abiotic factors at a site. Full article

(This article belongs to the Section Plant Ecology)

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12 pages, 1391 KiB

Open AccessArticle

Using Light Quality for Growth Control of Cucumber Seedlings in Closed-Type Plant Production System

by Hyeon Woo Jeong, Hye Ri Lee, Hyeon Min Kim, Hye Min Kim, Hee Sung Hwang and Seung Jae Hwang

Plants 2020, 9(5), 639; https://doi.org/10.3390/plants9050639 - 17 May 2020

Cited by 36 | Viewed by 3999

Abstract

During seedling production, growth control of seedlings is an important problem because the overgrowth of seedlings causes a decrease of seedling quality and has disadvantages after transplanting. In this study, we aim to evaluate the possibility of replacing chemical plant growth regulators using [...] Read more.

During seedling production, growth control of seedlings is an important problem because the overgrowth of seedlings causes a decrease of seedling quality and has disadvantages after transplanting. In this study, we aim to evaluate the possibility of replacing chemical plant growth regulators using light quality in a closed-type plant production system (CPPS) for cucumber seedling production. We used various light treatments, such as monochromatic or combined red (R) and blue (B), and combined R and B with UV-A or Far-red (Fr) light, to compare with a chemical plant growth regulator conventionally using in nursery farms. The combined R and B treatment decreased stem elongation and increased dry matter and compactness. UV-A treatment increased compactness but did not significantly affect the stem elongation or dry matter. Fr increased stem elongation and stem diameter and decreased compactness and dry matter. In leaf growth, combined R and B treatments and UV-A treatments increased leaf area, specific leaf weight, and SPAD value, and decreased leaf shape index. Fr treatments increased leaf area and leaf shape index and decreased specific leaf weight (SLW) and SPAD values. Cucumber seedlings have many different morphological changes, and R5B5 light quality was more effective in growth control due to higher compactness than chemical plant growth regulators. Also, R5B5 light quality has increased seedling quality, such as dry matter and SLW compared with fluorescent lamps. Thus, the use of light quality is a possible alternative to a chemical plant growth regulator. Full article

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