Roles of Soil and Roots Biotic and Abiotic Conditions in Fungal-Plant Interactions and Plant Performance

A special issue of Journal of Fungi (ISSN 2309-608X). This special issue belongs to the section "Environmental and Ecological Interactions of Fungi".

Deadline for manuscript submissions: closed (1 September 2022) | Viewed by 39759

Special Issue Editors


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Guest Editor
Institute for Sustainable Agriculture, CSIC, Alameda del Obispo s/n, 14004 Cordoba, Spain
Interests: agronomic management and disease development; biological control; disease presymptomatic detection; disease control; diversity of pathogen populations; field crops; genetic resistance; phytopathology; soil-borne pathogens
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Plant Science, MIGAL-Galilee Research Institute, Kiryat Shmona, Israel and Faculty of Sciences, Tel-Hai College, Tel-Hai, Israel
Interests: biological control; chemical control; crop protection; field studies; maize late wilt disease; plant disease; plant host–pathogen interactions; plant microflora
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The natural microorganisms inhabiting the plant rhizosphere (the roots’ surrounding habitat) may include diverse pathogens and various other non-pathogenic species. They live in complex communities in the soil and in the roots, and affect each other and the plants. They are also affected by abiotic surrounding and plants’ population structure. Some members of these communities maintain a mutually beneficial relationship with the plants, and may confer protective effects against pathogens. These valuable species can also assist plants, providing better immunity against environmental stresses. Other species are pathogens inhabiting the same ecological niche and either cooperate or compete for the same plant resources. This Special Issue welcomes papers focusing on recent scientific progress and innovation in the intriguing relationships between soil and root microorganisms and their implications for plants’ immunity to biotic and abiotic stresses. Our ability to understand and intervene in this fabric of relationships is essential to increase plant health and crop yields.

Dr. Leire Molinero-Ruiz
Dr. Ofir Degani
Guest Editors

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Keywords

  • Abiotic stresses
  • Biological control
  • Crop protection
  • Endophytes
  • Plant health
  • Soil microbiome
  • Soil microflora
  • Microbial interactions
  • Microorganism communities
  • Rhizosphere

Published Papers (15 papers)

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Research

13 pages, 1313 KiB  
Article
Increased Rice Susceptibility to Rice Blast Is Related to Post-Flowering Nitrogen Assimilation Efficiency
by Mathias Frontini, Jean-Benoit Morel, Antoine Gravot, Tanguy Lafarge and Elsa Ballini
J. Fungi 2022, 8(11), 1217; https://doi.org/10.3390/jof8111217 - 17 Nov 2022
Viewed by 1279
Abstract
Reducing nitrogen leaching and nitrous oxide emissions with the goal of more sustainability in agriculture implies better identification and characterization of the different patterns in nitrogen use efficiency by crops. However, a change in the ability of varieties to use nitrogen resources could [...] Read more.
Reducing nitrogen leaching and nitrous oxide emissions with the goal of more sustainability in agriculture implies better identification and characterization of the different patterns in nitrogen use efficiency by crops. However, a change in the ability of varieties to use nitrogen resources could also change the access to nutrient resources for a foliar pathogen such as rice blast and lead to an increase in the susceptibility of these varieties. This study focuses on the pre- and post-floral biomass accumulation and nitrogen uptake and utilization of ten temperate japonica rice genotypes grown in controlled conditions, and the relationship of these traits with molecular markers and susceptibility to rice blast disease. After flowering, the ten varieties displayed diversity in nitrogen uptake and remobilization. Surprisingly, post-floral nitrogen uptake was correlated with higher susceptibility to rice blast, particularly in plants fertilized with nitrogen. This increase in susceptibility is associated with a particular metabolite profile in the upper leavers of these varieties. Full article
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12 pages, 1965 KiB  
Article
Arbuscular Mycorrhizal Fungi Mediated Enhanced Biomass, Root Morphological Traits and Nutrient Uptake under Drought Stress: A Meta-Analysis
by Murugesan Chandrasekaran
J. Fungi 2022, 8(7), 660; https://doi.org/10.3390/jof8070660 - 23 Jun 2022
Cited by 31 | Viewed by 3042
Abstract
Drought stress remains the major constraint in affecting crop productivity in several arid and semi-arid areas highlighting climate change perspectives. Arbuscular mycorrhizal fungi (AMF) belong to a versatile class of plant–fungal symbiotic associations establishing drought stress alleviation. Nevertheless, the mechanistic mode of sustainable [...] Read more.
Drought stress remains the major constraint in affecting crop productivity in several arid and semi-arid areas highlighting climate change perspectives. Arbuscular mycorrhizal fungi (AMF) belong to a versatile class of plant–fungal symbiotic associations establishing drought stress alleviation. Nevertheless, the mechanistic mode of sustainable agriculture necessitates rigorous assessment for authentic and reproducible plant growth parameters. Understanding the plant growth promotion, root morphological changes, and nutrient uptake response in AMF-inoculated plants to drought is very important for sustainable agriculture. Therefore, conducted a meta-analysis of published research articles for determining the efficacy of AMF in alleviating drought stress. Overall analysis showed that AM inoculated plants had 49% higher plant growth promotion than the non-mycorrhizal plants under drought stress. Biomass analysis depicted the root dry weight increase by 49%, shoot dry weight increase by 54%, and total dry weight increase by 58% indicating plant biomass traits augmentation. Root morphological traits analysis corresponded to increased root length (37%), root surface (31%), and root volume (65%). Notably, nutrient uptake assessment showed variable increases in uptake patterns such as P uptake by 86%, N uptake by 35%, and K uptake by 46%. Furthermore, the prominent efficacy of AMF was significantly larger under drought for P uptake (p < 0.001) and root volume (p < 0.001) indicating the linear relationship between root length and P uptake. Thus, the present meta-analysis confirms that drought stress alleviation emancipated by AMF is mediated by root traits modification and phosphorous acquisition efficacy. Hence, meta-analyses along with experimental validations with field trial evaluations will certainly provide the AMF research for escalated applications for better plant productivity, stress alleviation, and sustainable agriculture. Full article
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21 pages, 28531 KiB  
Article
Crop Rotation and Minimal Tillage Selectively Affect Maize Growth Promotion under Late Wilt Disease Stress
by Ofir Degani, Asaf Gordani, Paz Becher, Assaf Chen and Onn Rabinovitz
J. Fungi 2022, 8(6), 586; https://doi.org/10.3390/jof8060586 - 30 May 2022
Cited by 10 | Viewed by 2817
Abstract
In recent years, worldwide scientific efforts towards controlling maize late wilt disease (LWD) have focused on eco-friendly approaches that minimize the environmental impact and health risks. This disease is considered to be the most severe threat to maize fields in Israel and Egypt, [...] Read more.
In recent years, worldwide scientific efforts towards controlling maize late wilt disease (LWD) have focused on eco-friendly approaches that minimize the environmental impact and health risks. This disease is considered to be the most severe threat to maize fields in Israel and Egypt, and a major growth restraint in India, Spain, and Portugal. Today’s most commonly used method for LWD control involving resistant maize genotypes is under constant risk from aggressive pathogen lines. Thus, this study’s objectives were to evaluate the effect of crop rotation and avoiding tillage on restraining the disease. Such an agrotechnical approach will support the continuity of soil mycorrhiza networks, which antagonize the disease’s causal agent, Magnaporthiopsis maydis. The method gained positive results in previous studies, but many knowledge gaps still need to be addressed. To this end, a dual-season study was conducted using the LWD hyper-susceptible maize hybrid, Megaton cv. The trials were performed in a greenhouse and in the field over full dual-growth seasons (wheat or clover as the winter crop followed by maize as the summer crop). In the greenhouse under LWD stress, the results clearly demonstrate the beneficial effect of maize crop rotation with clover and wheat on plant weight (1.4-fold), height (1.1–1.2-fold) and cob yield (1.8–2.4-fold), especially in the no-till soil. The clover-maize growth sequence excels in reducing disease impact (1.7-fold) and pathogen spread in the host tissues (3-fold). Even though the wheat-maize crop cycle was less effective, it still had better results than the commercial mycorrhizal preparation treatment and the uncultivated non-infected soil. The results were slightly different in the field. The clover-maize rotation also achieved the best growth promotion and disease restraint results (2.6-fold increase in healthy plants), but the maize rotation with wheat showed only minor efficiency. Interestingly, pre-cultivating the soil with clover had better results in no-till soil in both experiments. In contrast, the same procedure with wheat had a better impact when tillage was applied. It may be concluded that crop rotation and soil cultivation can be essential in reducing LWD, but other factors may affect this approach’s benefits in commercial field growth. Full article
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18 pages, 4485 KiB  
Article
P Starvation in Roses Leads to Strongly Genotype-Dependent Induction of P-Transporter Genes during Black Spot Leaf Disease
by Helena Sophia Domes, Enzo Neu, Marcus Linde and Thomas Debener
J. Fungi 2022, 8(6), 549; https://doi.org/10.3390/jof8060549 - 24 May 2022
Viewed by 1591
Abstract
Phosphorous starvation in plants has been reported to have contrasting effects on the interaction with pathogens in different plant pathogen systems and plant species. Both increases and decreases in susceptibility have been observed in numerous reports. Here, we analysed black spot infection and [...] Read more.
Phosphorous starvation in plants has been reported to have contrasting effects on the interaction with pathogens in different plant pathogen systems and plant species. Both increases and decreases in susceptibility have been observed in numerous reports. Here, we analysed black spot infection and the leaf expression of two plant phosphate transporters and one defence marker gene in roses after phosphorous starvation. We varied three factors: phosphate starvation versus full supply of phosphorous, black spot infection vs. mock inoculation, and different susceptible and resistant progeny of a biparental rose population. Black spot susceptibility or resistance was not significantly changed upon phosphate starvation in either compatible or incompatible interactions. The expression of phosphate transporters was strongly induced upon starvation, but in some genotypes, expression was altered by black spot interaction as well. The marker for pathogenic interactions was exclusively induced by interaction with black spot, but the expression was altered by a combination of phosphate starvation and interaction with the fungus in some genotypes. In summary, phosphate starvation has clear effects on the gene expression of phosphate transporters in rose leaves, and the interaction with a hemibiotrophic leaf pathogen is strongly genotype dependent. Full article
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16 pages, 2225 KiB  
Article
Chitosan and Nano-Chitosan for Management of Harpophora maydis: Approaches for Investigating Antifungal Activity, Pathogenicity, Maize-Resistant Lines, and Molecular Diagnosis of Plant Infection
by Eman O. Hassan, Tahsin Shoala, Amany M. F. Attia, Omnia A. M. Badr, Sabry Y. M. Mahmoud, Eman S. H. Farrag and Ibrahim A. I. EL-Fiki
J. Fungi 2022, 8(5), 509; https://doi.org/10.3390/jof8050509 - 16 May 2022
Cited by 5 | Viewed by 2006
Abstract
The rapid spread of late wilt disease among maize cultivations has resulted in serious economic losses in many countries. Harpophora maydis is the main cause of this destructive vascular disease. Here we evaluate the fungicidal activity of chitosan and nano-chitosan against six aggressive [...] Read more.
The rapid spread of late wilt disease among maize cultivations has resulted in serious economic losses in many countries. Harpophora maydis is the main cause of this destructive vascular disease. Here we evaluate the fungicidal activity of chitosan and nano-chitosan against six aggressive isolates of H. maydis collected from different Egyptian governorates. Pathogenicity tests for these isolates show that the highest disease severity was found for the Giza isolate. The isolates were tested for their response to the fungicide Permis, chitosan, and nano-chitosan treatments in vitro and in vivo. Nano-chitosan treatments fully inhibited the radial growth of H. maydis isolates at concentrations of 5 and 10 mM, compared to the full control growth (9 cm in diameter). On the other hand, in vitro, in vivo, and molecular diagnosis results showed high antifungal activity of chitosan and nano-chitosan compared to the Permis fungicide. Chitosan at the nano and normal scales proved a potent ability to enhance plant resistance in response to H. maydis. Disease severity (DS%) was extremely decreased among the tested cultivars by using nano-chitosan; the highest percentage was obtained on Giza 178 cv, where the DS% was 21.7% compared to 42.3% for the control. Meanwhile, the lowest percentage was obtained on Giza 180 cv with DS% 31.2 and the control with 41.3%. The plants treated with nano-chitosan showed the highest growth parameters for all cultivars. Such natural treatments could reduce the impact on the environment as they are non-pollutant natural compounds, protect the plants by reducing fungal activity, and induce plant resistance. Full article
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19 pages, 3306 KiB  
Article
Piriformospora indica and Azotobacter chroococcum Consortium Facilitates Higher Acquisition of N, P with Improved Carbon Allocation and Enhanced Plant Growth in Oryza sativa
by Prasun Bandyopadhyay, Bal Govind Yadav, Srinivasan Ganesh Kumar, Rahul Kumar, Karl-Heinz Kogel and Shashi Kumar
J. Fungi 2022, 8(5), 453; https://doi.org/10.3390/jof8050453 - 27 Apr 2022
Cited by 14 | Viewed by 3206
Abstract
The soil microbiome contributes to nutrient acquisition and plant adaptation to numerous biotic and abiotic stresses. Numerous studies have been conducted over the past decade showing that plants take up nutrients better when associated with fungi and additional beneficial bacteria that promote plant [...] Read more.
The soil microbiome contributes to nutrient acquisition and plant adaptation to numerous biotic and abiotic stresses. Numerous studies have been conducted over the past decade showing that plants take up nutrients better when associated with fungi and additional beneficial bacteria that promote plant growth, but the mechanisms by which the plant host benefits from this tripartite association are not yet fully understood. In this article, we report on a synergistic interaction between rice (Oryza sativa), Piriformospora indica (an endophytic fungus colonizing the rice roots), and Azotobacter chroococcum strain W5, a free-living nitrogen-fixing bacterium. On the basis of mRNA expression analysis and enzymatic activity, we found that co-inoculation of plant roots with the fungus and the rhizobacterium leads to enhanced plant growth and improved nutrient uptake compared to inoculation with either of the two microbes individually. Proteome analysis of O. sativa further revealed that proteins involved in nitrogen and phosphorus metabolism are upregulated and improve nitrogen and phosphate uptake. Our results also show that A. chroococcum supports colonization of rice roots by P. indica, and consequentially, the plants are more resistant to biotic stress upon co-colonization. Our research provides detailed insights into the mechanisms by which microbial partners synergistically promote each other in the interaction while being associated with the host plant. Full article
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17 pages, 2795 KiB  
Article
Mineral and Organic Fertilizers Distinctly Affect Fungal Communities in the Crop Rhizosphere
by Mikhail V. Semenov, George S. Krasnov, Vyacheslav M. Semenov and Ariena van Bruggen
J. Fungi 2022, 8(3), 251; https://doi.org/10.3390/jof8030251 - 01 Mar 2022
Cited by 28 | Viewed by 3343
Abstract
Fungi represent a diverse group of organisms that play an essential role in maintaining soil health and ecosystem functioning. Plant root exudates form nutrient-rich niches that harbor specific fungal communities, or so-called rhizosphere mycobiomes. The long-term application of fertilizers supplies the soil with [...] Read more.
Fungi represent a diverse group of organisms that play an essential role in maintaining soil health and ecosystem functioning. Plant root exudates form nutrient-rich niches that harbor specific fungal communities, or so-called rhizosphere mycobiomes. The long-term application of fertilizers supplies the soil with nutrients that may override the plant-related effects on rhizosphere fungal communities. Here, we assessed the effect of contrasting fertilization regimes on the composition, diversity, and abundance of bulk soil and rhizosphere mycobiomes of potato, white mustard, and maize under NPK (mineral fertilizers) or fresh cattle manure (organic fertilizers). Mineral and organic fertilizers led to distinct fungal communities in the rhizospheres of all studied crops, and the plant-related effects on the mycobiome were overridden by the effect of fertilization. The abundances of Ascomycota and Olpidiomycota were higher under manure, while the abundances of Basidiomycota and Monoblepharomycota increased under NPK. Manure input strongly increased fungal abundance but decreased fungal diversity and the total number of species. NPK had a slight effect on fungal diversity, but significantly increased the relative abundances of fungal phytopathogens, such as Alternaria and Fusarium. Our study shows that that potential plant species effects on the abundance and diversity of the rhizosphere mycobiomes are governed by long-term fertilization. Fertilization management could therefore be used to manipulate rhizosphere fungal communities and soilborne pathogen suppressiveness. Full article
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20 pages, 3144 KiB  
Article
Composition and Diversity of the Culturable Endophytic Community of Six Stress-Tolerant Dessert Plants Grown in Stressful Soil in a Hot Dry Desert Region
by Salam S. AlSharari, Fatma H. Galal and AlaaEddeen M. Seufi
J. Fungi 2022, 8(3), 241; https://doi.org/10.3390/jof8030241 - 28 Feb 2022
Cited by 10 | Viewed by 2316
Abstract
Saudi Arabia is part of a hot dry desert region and is characterized by stressful conditions. The main goal of this research was to identify endophytic fungal (EF) community composition, diversity and abundance in relation to their plant hosts and soil stress. The [...] Read more.
Saudi Arabia is part of a hot dry desert region and is characterized by stressful conditions. The main goal of this research was to identify endophytic fungal (EF) community composition, diversity and abundance in relation to their plant hosts and soil stress. The above-ground parts of six wild plants (Haloxylon salicornicum, Salsola kali, Heliotropium bacciferum, Erica verticillata, Salsola imbricata and Bienertia sinuspersici) were sampled, surface-sterilized and cut into small pieces, which were cultured and incubated for 4–6 weeks. Isolates were grouped and identified by using both morphological and ITS rDNA molecular data. The diversity and community structure of plant-endophyte associations were studied. A total of 455 EF isolates were grouped into 25 different taxa; 21 of which were identified at the species level, 2 at genus level and 2 were unclassified fungi. Here, 95.65% of the identified genera were Ascomycota; of which 36.36, 31.81 and 31.81% were members of the classes Dothideomycetes, Eurotiomycetes and Sordariomycetes, respectively. S. imbricata showed the highest isolation rate and colonization frequency (CF%) of EF when compared to other plant species. Additionally, S. imbricata demonstrated the highest species richness and species diversity of the EF community predominated by the genus Fusarium. Conclusively, the core culturable EF genera of six wild plants were identified (unculturable taxa were not identified in this study). The composition of the EF community was revealed to have a strong correlation to both the electrical conductivity and pH of the soil and a moderate correlation to both the host species and the host family. The abundance and diversity of EF communities of the six plants were environment-dependent. Full article
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14 pages, 659 KiB  
Article
Elucidating the Effect of Nutritional Imbalances of N and K on the Infection of Verticillium dahliae in Olive
by Ana López-Moral, Carlos Agustí-Brisach, Cristina Ruiz-Blancas, Begoña I. Antón-Domínguez, Esteban Alcántara and Antonio Trapero
J. Fungi 2022, 8(2), 139; https://doi.org/10.3390/jof8020139 - 29 Jan 2022
Cited by 6 | Viewed by 1800
Abstract
The effect of mineral nutrition on wilt diseases has been previously reported in many herbaceous hosts, though such an effect on Verticillium wilt in olive (Olea europaea L.; VWO), caused by Verticillium dahliae, is still uncertain. Field observations reveal that nitrogen [...] Read more.
The effect of mineral nutrition on wilt diseases has been previously reported in many herbaceous hosts, though such an effect on Verticillium wilt in olive (Olea europaea L.; VWO), caused by Verticillium dahliae, is still uncertain. Field observations reveal that nitrogen (N) excess or imbalances of N-potassium (K) favour VWO epidemics. However, this has yet to be demonstrated. Thus, the aim of this study was to evaluate the influences of nutritional imbalances of N and K in V. dahliae infection of olive. To this end, adjusted treatments with N excess (↑N+↑Na), K deficiency (↓K) and their combination (↑N+↑Na+↓K) were evaluated on the viability of V. dahliae microsclerotia (MS), as well as on disease development in olive plants. In parallel, the potential indirect effect of the treatments on the viability of conidia and MS of V. dahliae was evaluated through the stimuli of root exudates. Treatments ↑N+↑Na and ↑N+↑Na+↓K decreased MS germination and disease progress, whereas ↓K significantly increased both parameters. Root exudates from treated plants increased the conidia germination of V. dahliae but reduced the MS germination. The results of this study will be the basis for planning further research towards a better understanding of the effect of mineral nutrition on VWO. Full article
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12 pages, 1855 KiB  
Article
PCR-DGGE Analysis Proves the Suppression of Rhizoctonia and Sclerotium Root Rot Due to Successive Inoculations
by Mohsen Mohamed Elsharkawy, Shuhei Kuno, Mitsuro Hyakumachi, Yasser S. Mostafa, Saad A. Alamri and Sulaiman A. Alrumman
J. Fungi 2022, 8(2), 133; https://doi.org/10.3390/jof8020133 - 28 Jan 2022
Cited by 1 | Viewed by 2208
Abstract
The soil-borne pathogens Rhizoctonia solani and Sclerotium rolfsii have emerged as major pathogens of radish (Raphanus sativus) worldwide. The induction of soil suppressive of radish root rot disease was evaluated in soil repeatedly inoculated with R. solani, nonpathogenic binucleate Rhizoctonia [...] Read more.
The soil-borne pathogens Rhizoctonia solani and Sclerotium rolfsii have emerged as major pathogens of radish (Raphanus sativus) worldwide. The induction of soil suppressive of radish root rot disease was evaluated in soil repeatedly inoculated with R. solani, nonpathogenic binucleate Rhizoctonia sp. AG-A W1 (BNR) and S. rolfsii. The repeated inoculations of soil with R. solani and BNR significantly suppressed the disease severity of R. solani and S. rolfsii compared to the control. In contrast, the repeated inoculation of soil with S. rolfsii significantly suppressed only the pathogen, S. rolfsii. The community structure was examined using PCR-DGGE (polymerase chain reaction denaturing gradient gel electrophoresis) method. The bands of Trichoderma sp. were observed in the first, second and third inoculations of the soil with BNR. Similarly, bands of Trichoderma sp. were observed in the second and third inoculations of the soil with S. rolfsii and R. solani. Compared to the control, disease severity was significantly reduced in the soil repeatedly inoculated with S. rolfsii and R. solani . In conclusion, Trichoderma species were accumulated in specific patterns depending on the applied fungal inoculum in the suppressive soil. Full article
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25 pages, 22550 KiB  
Article
Native Rhizospheric and Endophytic Fungi as Sustainable Sources of Plant Growth Promoting Traits to Improve Wheat Growth under Low Nitrogen Input
by Akram H. Mohamed, Fayrouz H. Abd El-Megeed, Naziha M. Hassanein, Sameh H. Youseif, Peter F. Farag, Saleh A. Saleh, Basel A. Abdel-Wahab, Amnah Mohammed Alsuhaibani, Yosra A. Helmy and Ahmed M. Abdel-Azeem
J. Fungi 2022, 8(2), 94; https://doi.org/10.3390/jof8020094 - 19 Jan 2022
Cited by 14 | Viewed by 4173
Abstract
Wheat crops require effective nitrogen fertilization to produce high yields. Only half of chemical N2 fertilizers are absorbed into plants while the rest remains in the soil, causing environmental problems. Fungi could maximize nitrogen absorption, and from an environmental and biodiversity point [...] Read more.
Wheat crops require effective nitrogen fertilization to produce high yields. Only half of chemical N2 fertilizers are absorbed into plants while the rest remains in the soil, causing environmental problems. Fungi could maximize nitrogen absorption, and from an environmental and biodiversity point of view, there is an urgent necessity for bioprospecting native fungi associated with wild plants growing in harsh environments, e.g., St. Katherine Protectorate (SKP) in the arid Sinai. Recovered taxa, either endophytic and/or rhizospheric, were screened for their plant growth-promoting (PGP) traits. Eighteen fungal isolates (15 rhizospheric and 3 endophytic) belonging to anamorphic ascomycetes were recovered from 9 different wild plants, and their PGP traits (indole-3-acetic acid [IAA] production, phosphate solubilization, siderophore production, and hydrolytic enzyme production) were measured. Rhizospheric isolate NGB-WS14 (Chaetosphaeronema achilleae) produced high levels of IAA (119.1 μg mL−1) in the presence of tryptophan, while NGB-WS 8 (Acrophialophora levis) produced high IAA levels (42.4 μg mL−1) in the absence of tryptophan. The highest phosphate-solubilizing activity (181.9 μg mL−1) was recorded by NGB-WFS2 (Penicillium chrysogenum). Endophytic isolate NGB-WFE16 (Fusarium petersiae) exhibited a high percentage level of Siderophore Unit (96.5% SU). All isolates showed variability in the secretion of extracellular hydrolytic enzymes. Remarkably, all isolates had antagonistic activity (55.6% to 87.3% suppression of pathogen growth) against the pathogenic taxon Alternaria alternata (SCUF00001378) in the dual-assay results. Out of the 18 isolates, 4 rhizospheric and 1 endophytic isolate showed significant increases in shoot dry weight and shoot nitrogen and chlorophyll content of wheat plants subjected to low inputs of chemical nitrogen (N) fertilizers (50% reduction) compared with the non-inoculated control in a pot experiment. Potent taxa were subjected to sequencing for molecular confirmation of phenotypic identification. The retrieved ITS sequences in this study have been deposited in GenBank under accession numbers from LC642736 to LC642740. This study considered the first report of endophytic fungi of Cheilanthes vellea, a wild plant with PGPF which improves wheat growth. These results recommend using PGPF as inoculants to alleviate low nitrogen fertilization. Full article
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11 pages, 855 KiB  
Article
The Effect of Monochromatic LED Light Wavelengths and Photoperiods on Botrytis cinerea
by Neringa Rasiukevičiūtė, Aušra Brazaitytė, Viktorija Vaštakaitė-Kairienė, Asta Kupčinskienė, Pavelas Duchovskis, Giedrė Samuolienė and Alma Valiuškaitė
J. Fungi 2021, 7(11), 970; https://doi.org/10.3390/jof7110970 - 16 Nov 2021
Cited by 7 | Viewed by 3079
Abstract
Botrytis cinerea is a ubiquitous necrotrophic pathogen causing grey mould in economically important crops. Light effect in horticulture is undeniable and fungi also react to light. Selected specific light-emitting diodes (LEDs) and photoperiods can be used for fungal pathogen inhibition. This study aimed [...] Read more.
Botrytis cinerea is a ubiquitous necrotrophic pathogen causing grey mould in economically important crops. Light effect in horticulture is undeniable and fungi also react to light. Selected specific light-emitting diodes (LEDs) and photoperiods can be used for fungal pathogen inhibition. This study aimed to evaluate how LED light wavelengths and photoperiods affect the growth parameters of B. cinerea. The morphological (mycelium appearance, sclerotia distribution) and phenotypic (conidia presence and size, mycelium growth rate, recovery) characteristics of the fungal pathogen B. cinerea were evaluated under royal blue 455 nm, blue 470 nm, cyan 505 nm, yellow 590 nm, and red 627 nm LED lights at various photoperiods (4, 8, 12, 16, 20, 24 h). The results revealed that the light conditions and photoperiods influenced the B. cinerea morphological and phenotypic characteristics. Overall, the highest B. cinerea inhibition was under yellow (590 nm) LED light at 4 and 8 h photoperiods. Conidia did not form under blue 455 nm at 8, 16, 20, and 24 h photoperiods. Therefore, it can be assumed that the phenotypic and morphological features of B. cinerea depend on the specific photoperiod and LED light wavelength. The results allowed an exploration of original research approaches, raised new scientific questions for further investigation, and suggested new green plant protection solutions. Full article
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29 pages, 6815 KiB  
Article
Phosphorus Starvation- and Zinc Excess-Induced Astragalus sinicus AsZIP2 Zinc Transporter Is Suppressed by Arbuscular Mycorrhizal Symbiosis
by Xianan Xie, Xiaoning Fan, Hui Chen and Ming Tang
J. Fungi 2021, 7(11), 892; https://doi.org/10.3390/jof7110892 - 22 Oct 2021
Cited by 2 | Viewed by 2030
Abstract
Zinc (Zn) is one of the most essential micronutrients for plant growth and metabolism, but Zn excess can impair many basic metabolic processes in plant cells. In agriculture, crops often experience low phosphate (Pi) and high Zn double nutrient stresses because of inordinate [...] Read more.
Zinc (Zn) is one of the most essential micronutrients for plant growth and metabolism, but Zn excess can impair many basic metabolic processes in plant cells. In agriculture, crops often experience low phosphate (Pi) and high Zn double nutrient stresses because of inordinate agro-industrial activities, while the dual benefit of arbuscular mycorrhizal (AM) fungi protects plants from experiencing both deficient and toxic nutrient stresses. Although crosstalk between Pi and Zn nutrients in plants have been extensively studied at the physiological level, the molecular basis of how Pi starvation triggers Zn over-accumulation in plants and how AM plants coordinately modulate the Pi and Zn nutrient homeostasis remains to be elucidated. Here, we report that a novel AsZIP2 gene, a Chinese milk vetch (Astragalus sinicus) member of the ZIP gene family, participates in the interaction between Pi and Zn nutrient homeostasis in plants. Phylogenetic analysis revealed that this AsZIP2 protein was closely related to the orthologous Medicago MtZIP2 and Arabidopsis AtZIP2 transporters. Gene expression analysis indicated that AsZIP2 was highly induced in roots by Pi starvation or Zn excess yet attenuated by arbuscular mycorrhization in a Pi-dependent manner. Subcellular localization and heterologous expression experiments further showed that AsZIP2 encoded a functional plasma membrane-localized transporter that mediated Zn uptake in yeast. Moreover, overexpression of AsZIP2 in A. sinicus resulted in the over-accumulation of Zn concentration in roots at low Pi or excessive Zn concentrations, whereas AsZIP2 silencing lines displayed an even more reduced Zn concentration than control lines under such conditions. Our results reveal that the AsZIP2 transporter functioned in Zn over-accumulation in roots during Pi starvation or high Zn supply but was repressed by AM symbiosis in a Pi-dependent manner. These findings also provide new insights into the AsZIP2 gene acting in the regulation of Zn homeostasis in mycorrhizal plants through Pi signal. Full article
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18 pages, 2782 KiB  
Article
Crop Cycle and Tillage Role in the Outbreak of Late Wilt Disease of Maize Caused by Magnaporthiopsis maydis
by Ofir Degani, Asaf Gordani, Paz Becher and Shlomit Dor
J. Fungi 2021, 7(9), 706; https://doi.org/10.3390/jof7090706 - 28 Aug 2021
Cited by 6 | Viewed by 2315
Abstract
The destructive maize late wilt disease (LWD) has heavy economic implications in highly infected areas such as Israel, Egypt, and Spain. The disease outbreaks occur near the harvest, leading to total yield loss in severe cases. Crop rotation has long been known as [...] Read more.
The destructive maize late wilt disease (LWD) has heavy economic implications in highly infected areas such as Israel, Egypt, and Spain. The disease outbreaks occur near the harvest, leading to total yield loss in severe cases. Crop rotation has long been known as an effective means to reduce plant diseases. Indeed, agricultural soil conservation practices that can promote beneficial soil and root fungi have become increasingly important. Such methods may have a bioprotective effect against Magnaporthiopsis maydis, the LWD causal agent. In this two-year study, we tested the role of crop rotation of maize with either wheat or clover and the influence of minimum tillage in restricting LWD. In the first experiment, wheat and clover were grown in pots with LWD infected soil in a greenhouse over a full winter growth period. These cultivations were harvested in the spring, and each pot’s group was split into two subgroups that underwent different land processing practices. The pots were sown with LWD-sensitive maize cultivar and tested over a whole growth period against control soils without crop rotation or soil with commercial mycorrhizal preparation. The maize crop rotation with wheat without tillage achieved prominent higher growth indices than the control and the clover crop cycle. Statistically significant improvement was measured in the non-tillage wheat soil pots in sprout height 22 days after sowing, in the healthy plants at the season’s end (day 77), and in shoot and cob wet weight (compared to the control). This growth promotion was accompanied by a 5.8-fold decrease in pathogen DNA in the plant stems. The tillage in the wheat-maize growth sequence resulted in similar results with improved shoot wet-weight throughout the season. In contrast, when maize was grown after clover, the tillage reduced this parameter. The addition of commercial mycorrhizal preparation to the soil resulted in higher growth measures than the control but was less efficient than the wheat crop cycle. These results were supported by a subsequent similar experiment that relied on soil taken from commercial wheat or clover fields. Here too, the wheat-maize growth cycle (without permanent effect for the tillage) achieved the best results and improved the plants’ growth parameters and immunity against LWD and lowered pathogen levels. In conclusion, the results of this study suggest that wheat and perhaps other crops yet to be inspected, together with the adjusted tillage system, may provide plants with better defense against the LWD pathogen. Full article
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21 pages, 3872 KiB  
Article
Insights into the Bioprospecting of the Endophytic Fungi of the Medicinal Plant Palicourea rigida Kunth (Rubiaceae): Detailed Biological Activities
by Igor Romeiro dos Santos, Ahmed M. Abdel-Azeem, Marwa T. Mohesien, Magdalena Piekutowska, Donia H. Sheir, Lucas Leonardo da Silva, Camila da Silva Castro, Daniel Diego Costa Carvalho, Jadson Diogo Pereira Bezerra, Hosam A. Saad, Leonardo Luiz Borges and Solange Xavier-Santos
J. Fungi 2021, 7(9), 689; https://doi.org/10.3390/jof7090689 - 25 Aug 2021
Cited by 6 | Viewed by 2847
Abstract
A multitude of plants from the Brazilian savanna are known for their medicinal properties. Many plants contain endophytic fungi, which lead to the production of bioactive compounds by both the fungi and their hosts. This study investigated the bioprospecting of endophytic fungi recovered [...] Read more.
A multitude of plants from the Brazilian savanna are known for their medicinal properties. Many plants contain endophytic fungi, which lead to the production of bioactive compounds by both the fungi and their hosts. This study investigated the bioprospecting of endophytic fungi recovered from the leaves of Palicourea rigida, a native medicinal plant of the Brazilian savanna. Four fungal taxa (Colletotrichum sp. SXS649, Pestalotiopsis sp. SXS650, the order Botryosphaeriales SXS651, and Diaporthe sp. SXS652) were recovered. The phenolic, flavonoid, extracellular degrading enzymes (amylase, cellulase, protease, and tannase) and antioxidant activity of these taxa were determined. Evaluation of the antimicrobial activity showed that the Botryosphaeriales SXS651 extract displays a minimum inhibitory concentration (MIC) of 23.20 mg mL−1 against Staphylococcus epidermidis and Pseudomonas aeruginosa, and the Diaporthe sp. SXS652 extract exhibited an MIC of 27.00 mg mL−1 against Escherichia coli. The Colletotrichum sp. SXS649 isolate inhibited tumors in potato discs by 69% at a concentration of 9.70 mg mL−1. All isolates had potential bioremediation criteria against soil contaminated with soybean oil, as proved by a high percentage of germination of Lactuca sativa and a reduction in phytotoxicity. Furthermore, the taxa under investigation demonstrated antagonistic action to phytopathogenic fungi, namely, Aspergillus niger, Inonotus rickii, Pestalotiopsis mangiferae, and Coniophora puteana, with an inhibition range between 34.2% and 76.9%. The preliminary toxicity assessment showed that all isolates possessed an LC50 of less than 100 mg mL−1 to the microcrustacean Artemia salina. These results indicate that the endophytic fungi of the Brazilian savanna are promising candidates for biotechnological and industrial applications and, in agricultural applications, for the biological control of phytopathogenic fungi. Full article
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