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13 pages, 3166 KiB

Open AccessArticle

Optimization of an Alternative Culture Medium for Phycocyanin Production from Arthrospira platensis under Laboratory Conditions

by Daniel Alberto Freire Balseca, Kimberly Susana Castro Reyes and María Elena Maldonado Rodríguez

Microorganisms 2024, 12(2), 363; https://doi.org/10.3390/microorganisms12020363 - 10 Feb 2024

Viewed by 776

Abstract

Arthrospira platensis, known as spirulina, is a cyanobacterium with multiple nutritional benefits, as it contains substantial amounts of proteins, fatty acids, and pigments. However, the production of this microalga has faced significant challenges, primarily related to the cost and composition of the [...] Read more.

Arthrospira platensis, known as spirulina, is a cyanobacterium with multiple nutritional benefits, as it contains substantial amounts of proteins, fatty acids, and pigments. However, the production of this microalga has faced significant challenges, primarily related to the cost and composition of the required culture medium for its optimal growth. This study focused on optimizing two nitrogen sources (urea and potassium nitrate) to maximize the growth of A. platensis and the production of phycocyanin, a photosynthetic pigment of significant commercial value. Optimization was performed using the response surface methodology (RSM) with a central composite design (CCD). Analysis of variance (ANOVA) was employed to validate the model, which revealed that the different concentrations of urea were statistically significant (p < 0.05) for biomass and phycocyanin production. However, potassium nitrate (KNO₃) showed no significant influence (p > 0.05) on the response variables. The RSM analysis indicated that the optimal concentrations of KNO₃ and urea to maximize the response variables were 3.5 g L⁻¹ and 0.098 g L⁻¹, respectively. This study offers valuable perspectives for the efficient production of A. platensis while reducing production costs for its cultivation on a larger scale. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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33 pages, 23892 KiB

Open AccessArticle

Bacillus subtilis 26D Triggers Induced Systemic Resistance against Rhopalosiphum padi L. by Regulating the Expression of Genes AGO, DCL and microRNA in Bread Spring Wheat

by Sergey D. Rumyantsev, Svetlana V. Veselova, Guzel F. Burkhanova, Valentin Y. Alekseev and Igor V. Maksimov

Microorganisms 2023, 11(12), 2983; https://doi.org/10.3390/microorganisms11122983 - 14 Dec 2023

Cited by 1 | Viewed by 1154

Abstract

Bacillus subtilis 26D is a plant growth-promoting endophytic bacteria capable of inducing systemic resistance through the priming mechanism, which includes plant genome reprogramming and the phenomenon of RNA interference (RNAi) and microRNA (miRNAs). The phloem-feeding insect bird cherry-oat aphid Rhopalosiphum padi L. is [...] Read more.

Bacillus subtilis 26D is a plant growth-promoting endophytic bacteria capable of inducing systemic resistance through the priming mechanism, which includes plant genome reprogramming and the phenomenon of RNA interference (RNAi) and microRNA (miRNAs). The phloem-feeding insect bird cherry-oat aphid Rhopalosiphum padi L. is a serious pest that causes significant damage to crops throughout the world. However, the function of plant miRNAs in the response to aphid infestation remains unclear. The results of this work showed that B. subtilis 26D stimulated aphid resistance in wheat plants, inducing the expression of genes of hormonal signaling pathways ICS, WRKY13, PR1, ACS, EIN3, PR3, and ABI5. In addition, B. subtilis 26D activated the RNAi mechanism and regulated the expression of nine conserved miRNAs through activation of the ethylene, salicylic acid (SA), and abscisic acid (ABA) signaling pathways, which was demonstrated by using treatments with phytohormones. Treatment of plants with SA, ethylene, and ABA acted in a similar manner to B. subtilis 26D on induction of the expression of the AGO4, AGO5 and DCL2, DCL4 genes, as well as the expression of nine conserved miRNAs. Different patterns of miRNA expression were found in aphid-infested plants and in plants treated with B. subtilis 26D or SA, ethylene, and ABA and infested by aphids, suggesting that miRNAs play multiple roles in the plant response to phloem-feeding insects, associated with effects on hormonal signaling pathways, redox metabolism, and the synthesis of secondary metabolites. Our study provides new data to further elucidate the fine mechanisms of bacterial-induced priming. However, further extensive work is needed to fully unravel these mechanisms. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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19 pages, 4195 KiB

Open AccessArticle

Influence of the Antibiotic Oxytetracycline on the Morphometric Characteristics and Endophytic Bacterial Community of Lettuce (Lactuca sativa L.)

by Natalia Danilova, Gulnaz Galieva, Polina Kuryntseva, Svetlana Selivanovskaya and Polina Galitskaya

Microorganisms 2023, 11(12), 2828; https://doi.org/10.3390/microorganisms11122828 - 21 Nov 2023

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Abstract

Antibiotics enter the soil with compost prepared from livestock manures and other sources. There is concern that they may influence plant growth and cause antibiotic resistance in soil and plant endospheric microbiomes. In the present work, lettuce plants were cultivated in soil and [...] Read more.

Antibiotics enter the soil with compost prepared from livestock manures and other sources. There is concern that they may influence plant growth and cause antibiotic resistance in soil and plant endospheric microbiomes. In the present work, lettuce plants were cultivated in soil and hydroponics spiked with oxytetracycline (0, 15, and 300 mg × kg⁻¹ and 0, 15, and 50 mg × L^–1, respectively) during a 28-day greenhouse experiment. It was revealed that the antibiotic reduced the chlorophyll content, the biomass, and the length of the roots and stems by 1.4–4.7, 1.8–39, 2.5–3.2, and 1.8–6.3 times in soil and in hydroponics. The copy numbers of the tet(A) and tet(X) genes were revealed to be 4.51 × 10³–1.58 × 10⁵ and 8.36 × 10⁶–1.07 × 10⁸ copies × g^–1, respectively, suggesting the potential migration of these genes from soil/hydroponics to plant roots and leaves. According to a non-metric multidimensional scaling (NMDS) analysis of the 16S rRNA amplicon sequencing data, endospheric bacterial communities were similar in leaves and roots independent of the growing substrate and antibiotic concentration. While soil bacterial communities were unaffected by the presence of antibiotics, hydroponic communities exhibited dependency, likely attributable to the absence of the mitigating effect of soil particle absorption. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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12 pages, 3197 KiB

Open AccessArticle

Evidence of High Genetic Diversity and Differences in the Population Diversity of the Eucalyptus Leaf Blight Pathogen Calonectria pseudoreteaudii from Diseased Leaves and Soil in a Plantation in Guangxi, China

by Wenxia Wu, Wenwen Li, Feifei Liu and Shuaifei Chen

Microorganisms 2023, 11(11), 2785; https://doi.org/10.3390/microorganisms11112785 - 16 Nov 2023

Viewed by 684

Abstract

Calonectria pseudoreteaudii is an important causal agent of Eucalyptus leaf blight in southern China. This pathogen causes Eucalyptus tree disease across numerous regions in southern China. In addition to diseased leaves, C. pseudoreteaudii has occasionally been isolated from soil in Eucalyptus plantations. The [...] Read more.

Calonectria pseudoreteaudii is an important causal agent of Eucalyptus leaf blight in southern China. This pathogen causes Eucalyptus tree disease across numerous regions in southern China. In addition to diseased leaves, C. pseudoreteaudii has occasionally been isolated from soil in Eucalyptus plantations. The aim of this study was to clarify whether C. pseudoreteaudii causing Eucalyptus leaf blight in China is mainly clonally reproduced and to determine the potential spreading mechanism of C. pseudoreteaudii between diseased leaves and soil. To this end, 10 polymorphic microsatellite markers were analyzed to detect the genetic diversity of 97 C. pseudoreteaudii isolates from diseased leaves and soil in a Eucalyptus plantation in Guangxi Zhuang Autonomous Region, southern China. The analysis showed that the genetic diversity of the isolates from both the diseased leaves and soil was high. However, the gene and genotype diversity of the C. pseudoreteaudii isolates from diseased leaves were higher than those of the isolates from the soil. Moreover, all genotypes detected in the isolates from the soil were also found in the isolates from the diseased leaves. Structural analyses did not show clear population structures related to the population substrates of the diseased leaves or soil, and molecular variance analyses indicated that no significant genetic differentiation existed between the diseased leaf and soil populations. These results suggest that C. pseudoreteaudii in soil spreads from diseased leaves, and that an asexual cycle is the primary reproductive mode in both diseased leaf and soil populations. This is the first study on the genetic diversity and population structure of C. pseudoreteaudii. The high genetic diversity and spread pathways of this pathogen may pose challenges in controlling the disease. C. pseudoreteaudii from both diseased leaves and soils in Eucalyptus plantations needs to be carefully monitored for disease control and management. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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16 pages, 4461 KiB

Open AccessArticle

Stimulation of the Defense Mechanisms of Potatoes to a Late Blight Causative Agent When Treated with Bacillus subtilis Bacteria and Chitosan Composites with Hydroxycinnamic Acids

by Liubov Yarullina, Ekaterina A. Cherepanova, Guzel F. Burkhanova, Antonina V. Sorokan, Evgenia A. Zaikina, Vyacheslav O. Tsvetkov, Ildar S. Mardanshin, Ildus Y. Fatkullin, Joanna N. Kalatskaja, Ninel A. Yalouskaya and Victoria V. Nikalaichuk

Microorganisms 2023, 11(8), 1993; https://doi.org/10.3390/microorganisms11081993 - 02 Aug 2023

Cited by 1 | Viewed by 1033

Abstract

Phytophthora infestans is, worldwide, one of the main causal agents of epiphytotics in potato plantings. Prevention strategies demand integrated pest management, including modeling of beneficial microbiomes of agroecosystems combining microorganisms and natural products. Chitooligosaccharides and their derivatives have great potential to be used [...] Read more.

Phytophthora infestans is, worldwide, one of the main causal agents of epiphytotics in potato plantings. Prevention strategies demand integrated pest management, including modeling of beneficial microbiomes of agroecosystems combining microorganisms and natural products. Chitooligosaccharides and their derivatives have great potential to be used by agrotechnology due to their ability to elicit plant immune reactions. The effect of combining Bacillus subtilis 26D and 11VM and conjugates of chitin with hydroxycinnamates on late blight pathogenesis was evaluated. Mechanisms for increasing the resistance of potato plants to Phytophthora infestans were associated with the activation of the antioxidant system of plants and an increase in the level of gene transcripts that encode PR proteins: basic protective protein (PR-1), thaumatin-like protein (PR-5), protease inhibitor (PR-6), and peroxidase (PR-9). The revealed activation of the expression of marker genes of systemic acquired resistance and induced systemic resistance under the influence of the combined treatment of plants with B. subtilis and conjugates of chitin with hydroxycinnamates indicates that, in this case, the development of protective reactions in potato plants to late blight proceeds synergistically, where B. subtilis primes protective genes, and chitosan composites act as a trigger for their expression. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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16 pages, 2516 KiB

Open AccessArticle

Effects of Short-Term Nitrogen Addition on Soil Fungal Community Increase with Nitrogen Addition Rate in an Alpine Steppe at the Source of Brahmaputra

by Shaolin Huang, Chengqun Yu, Gang Fu, Wei Sun, Shaowei Li, Fusong Han and Jianyu Xiao

Microorganisms 2023, 11(8), 1880; https://doi.org/10.3390/microorganisms11081880 - 25 Jul 2023

Viewed by 714

Abstract

The soil fungal community plays a crucial role in terrestrial decomposition and biogeochemical cycles. However, the responses of the soil fungal community to short-term nitrogen addition and its related dominant drivers still remain unclear. To address this gap, we conducted an experiment to [...] Read more.

The soil fungal community plays a crucial role in terrestrial decomposition and biogeochemical cycles. However, the responses of the soil fungal community to short-term nitrogen addition and its related dominant drivers still remain unclear. To address this gap, we conducted an experiment to explore how different levels of nitrogen addition (five levels: 0, 2.5, 5, 10, and 20 g N m⁻² y⁻¹) affected the soil fungal community in an alpine steppe at the source of Brahmaputra. Results showed that the reduced magnitudes of soil fungal species and phylogenetic α-diversity increased with the increasing nitrogen addition rate. Nitrogen addition significantly changed the community composition of species, and the dissimilarity of the soil fungal community increased with the increasing nitrogen addition rate, with a greater dissimilarity observed in the superficial soil (0–10 cm) compared to the subsurface soil (10–20 cm). Increases in the soil nitrogen availability were found to be the predominant factor in controlling the changes in the soil fungal community with the nitrogen addition gradient. Therefore, short-term nitrogen addition can still cause obvious changes in the soil fungal community in the alpine grassland at the source of Brahmaputra. We should not underestimate the potential influence of future nitrogen deposition on the soil fungal community in the high-altitude grassland of the Qinghai–Tibet Plateau. Adverse effects on the soil fungal community should be carefully considered when nitrogen fertilizer is used for ecosystem restoration of the alpine grassland of the Qinghai–Tibet Plateau. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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18 pages, 4020 KiB

Open AccessArticle

Endophytic Plant Growth-Promoting Bacterium Bacillus subtilis Reduces the Toxic Effect of Cadmium on Wheat Plants

by Dilara Maslennikova, Igor Koryakov, Ruslan Yuldashev, Irina Avtushenko, Albina Yakupova and Oksana Lastochkina

Microorganisms 2023, 11(7), 1653; https://doi.org/10.3390/microorganisms11071653 - 25 Jun 2023

Cited by 3 | Viewed by 1507

Abstract

Heavy metal ions, in particular cadmium (Cd), have a negative impact on the growth and productivity of major crops, including wheat. The use of environmentally friendly approaches, in particular, bacteria that have a growth-stimulating and protective effect, can increase the resistance of plants. [...] Read more.

Heavy metal ions, in particular cadmium (Cd), have a negative impact on the growth and productivity of major crops, including wheat. The use of environmentally friendly approaches, in particular, bacteria that have a growth-stimulating and protective effect, can increase the resistance of plants. The effects of the pre-sowing seed treatment with the plant growth-promoting endophyte Bacillus subtilis 10-4 (BS) on cadmium acetate (Cd)-stressed Triticum aestivum L. (wheat) growth, photosynthetic pigments, oxidative stress parameters, roots’ lignin content, and Cd ions accumulation in plants were analyzed. The results showed that the tested Cd-tolerant BS improved the ability of wheat seeds to germinate in the presence of different Cd concentrations (0, 0.1, 0.5, and 1 mM). In addition, the bacterial treatment significantly decreased the damaging effects of Cd stress (1 mM) on seedlings’ linear dimensions (lengths of roots and shoots), biomass, as well as on the integrity and permeability of the cell walls (i.e., lipid peroxidation and electrolyte leakage) and resulted in reduced H₂O₂ generation. The pretreatment with BS prevented the Cd-induced degradation of the leaf photosynthetic pigments chlorophyll (Chl) a, Chl b, and carotenoids. Moreover, the bacterial treatment intensified the lignin deposition in the roots under normal and, especially, Cd stress conditions, thereby enhancing the barrier properties of the cell wall. This manifested in a reduced Cd ions accumulation in the roots and in the restriction of its translocation to the aboveground parts (shoots) of the bacterized plants under Cd stress in comparison with non-bacterized controls. Thus, the pre-sowing seed treatment with the endophyte BS may serve as an eco-friendly approach to improve wheat production in Cd-contaminated areas. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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17 pages, 9403 KiB

Open AccessArticle

Differential Responses of Bacterial and Fungal Communities to Siderophore Supplementation in Soil Affected by Tobacco Bacterial Wilt (Ralstonia solanacearum)

by Yunxin Shen, Jiangyuan Zhao, Xuefeng Zou, Zhufeng Shi, Yongqin Liao, Yonghong He, Hang Wang, Qibin Chen, Peiweng Yang and Minggang Li

Microorganisms 2023, 11(6), 1535; https://doi.org/10.3390/microorganisms11061535 - 09 Jun 2023

Viewed by 1365

Abstract

Siderophores secreted by microorganisms can promote ecological efficiency and could be used to regulate the unbalanced microbial community structure. The influence of the siderophore activity of Trichoderma yunnanense strain 2-14F2 and Beauveria pseudobassiana strain (2-8F2) on the physiological/biochemical functions and community structure of [...] Read more.

Siderophores secreted by microorganisms can promote ecological efficiency and could be used to regulate the unbalanced microbial community structure. The influence of the siderophore activity of Trichoderma yunnanense strain 2-14F2 and Beauveria pseudobassiana strain (2-8F2) on the physiological/biochemical functions and community structure of soil microbes affected by tobacco bacterial wilt (TBW) was studied. DNS Colorimetry and Biolog-eco plates were used to quantify the impacts of strain siderophores on soil enzyme activities and microbial metabolism. Based on Illumina MiSeq high-throughput sequencing, the soil 16S rDNA and ITS sequences were amplified to dissect the response characteristics of alpha/beta diversity and the structure/composition of a soil microbial community toward siderophores. The KEGG database was used to perform the PICRUSt functional prediction of the microbial community. We found that siderophores of 2-14F2 and 2-8F2, at certain concentrations, significantly increased the activities of sucrase (S-SC) and urease (S-UE) in the TBW soil and enhanced the average well color development (AWCD, carbon source utilization capacity) of the microbial community. The metabolic capacity of the diseased soil to amino acids, carbohydrates, polymers, aromatics, and carboxylic acids also increased significantly. The response of the bacterial community to siderophore active metabolites was more significant in alpha diversity, while the beta diversity of the fungal community responded more positively to siderophores. The relative abundance of Actinobacteria, Chloroflexi, and Acidobacteria increased and was accompanied by reductions in Proteobacteria and Firmicutes. LEfSe analysis showed that Pseudonocardiaceae, Gemmatimonas, Castellaniella, Chloridiumand and Acrophialophora altered the most under different concentrations of siderophore active metabolites. The PICRUSt functional prediction results showed that siderophore increased the abundance of the redox-related enzymes of the microbial community in TBW soil. The BugBase phenotypic prediction results showed that the siderophore activity could decrease the abundance of pathogenic bacteria. The study concludes that siderophore activity could decrease the abundance of pathogenic bacteria and regulate the composition of the microbial community in TBW soil. The activities of sucrase (S-SC) and urease (S-UE) in TBW soil were significantly increased. Overall, the siderophore regulation of community structures is a sustainable management strategy for soil ecosystems. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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14 pages, 1948 KiB

Open AccessArticle

Characterization of Bacillus pumilus Strains with Targeted Gene Editing for Antimicrobial Peptides and Sporulation Factor

by Iuliia V. Danilova, Iuliia A. Vasileva, Ajgul I. Gilmutdinova, Ilona V. Dyadkina, Liya K. Khusnullina, Damir I. Khasanov, Natalia L. Rudakova and Margarita R. Sharipova

Microorganisms 2023, 11(6), 1508; https://doi.org/10.3390/microorganisms11061508 - 06 Jun 2023

Cited by 1 | Viewed by 1455

Abstract

Due to their capacity to produce antimicrobial peptides that can prevent the growth of diseases, many Bacillus spp. are beneficial to plants. In this study, we looked into the antagonistic activity of the B. pumilus 3-19 strain and its derivatives following targeted genome [...] Read more.

Due to their capacity to produce antimicrobial peptides that can prevent the growth of diseases, many Bacillus spp. are beneficial to plants. In this study, we looked into the antagonistic activity of the B. pumilus 3-19 strain and its derivatives following targeted genome editing. Two peptide genes with antibacterial action, bacilysin (bac) and bacteriocin (bact), and the sigF gene, which encodes the sigma factor of sporulation, were specifically inactivated using the CRISPR-Cas9 system in the genome of B. pumilus 3-19. Antibacterial activity against B. cereus and Pantoea brenneri decreased as a result of the inactivation of target genes in the B. pumilus 3-19 genome, with a noticeable effect against bacilysin. The growth dynamics of the culture changed when the bac, bact, and sigF genes were inactivated, and the altered strains had less proteolytic activity. An asporogenic mutant of B. pumilus 3-19 was obtained by inactivating the sigF gene. It has been proven that bacilysin plays a unique part in the development of B. pumilus 3-19’s antagonistic action against soil microorganisms. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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16 pages, 2754 KiB

Open AccessArticle

Biofilm Formation by Mutant Strains of Bacilli under Different Stress Conditions

by Margarita Sharipova, Natalia Rudakova, Ayslu Mardanova, Vladimir Evtugyn, Yaw Akosah, Iuliia Danilova and Aliya Suleimanova

Microorganisms 2023, 11(6), 1486; https://doi.org/10.3390/microorganisms11061486 - 02 Jun 2023

Cited by 6 | Viewed by 1393

Abstract

Bacillus subtilis is traditionally classified as a PGPR that colonizes plant roots through biofilm formation. The current study focused on investigating the influence of various factors on bacilli biofilm formation. In the course of the study, the levels of biofilm formation by the [...] Read more.

Bacillus subtilis is traditionally classified as a PGPR that colonizes plant roots through biofilm formation. The current study focused on investigating the influence of various factors on bacilli biofilm formation. In the course of the study, the levels of biofilm formation by the model strain B. subtilis WT 168 and on its basis created regulatory mutants, as well as strains of bacilli with deleted extracellular proteases under conditions of changes in temperature, pH, salt and oxidative stress and presence of divalent metals ions. B. subtilis 168 forms halotolerant and oxidative stress-resistant biofilms at a temperature range of 22 °C–45 °C and a pH range of 6–8.5. The presence of Ca²⁺, Mn²⁺ and Mg²⁺ upsurges the biofilm development while an inhibition with Zn²⁺. Biofilm formation level was higher in protease-deficient strains. Relative to the wild-type strain, degU mutants showed a decrease in biofilm formation, abrB mutants formed biofilms more efficiently. spo0A mutants showed a plummeted film formation for the first 36 h, followed by a surge after. The effect of metal ions and NaCl on the mutant biofilms formation is described. Confocal microscopy indicated that B. subtilis mutants and protease-deficient strains differ in matrix structure. The highest content of amyloid-like proteins in mutant biofilms was registered for degU-mutants and protease-deficient strains. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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11 pages, 23441 KiB

Open AccessArticle

Beneficial Effect of the New Leptodophora sp. Strain on Development of Blueberry Microclones in the Process of Their Adaptation

by Yulia S. Topilina, Evgeniya A. Luk‘yanova, Lubov B. Glukhova, Margarita N. Shurupova, Anna L. Gerasimchuk, Yulia A. Frank and Dmitry V. Antsiferov

Microorganisms 2023, 11(6), 1406; https://doi.org/10.3390/microorganisms11061406 - 26 May 2023

Cited by 1 | Viewed by 979

Abstract

The paper searches for new solutions for the development of highbush blueberry orchards (Vaccinium corymbosum L. (1753)) in Western Siberia. All species of the genus Vaccinium display special symbiotic mycorrhizal associations with root systems—ericoid mycorrhiza, which essentially enhances the formation of adventitious [...] Read more.

The paper searches for new solutions for the development of highbush blueberry orchards (Vaccinium corymbosum L. (1753)) in Western Siberia. All species of the genus Vaccinium display special symbiotic mycorrhizal associations with root systems—ericoid mycorrhiza, which essentially enhances the formation of adventitious and lateral roots. For the first time, we obtained pure cultures of micromycetes associated with the roots of wild species of the family Ericaceae in the Tomsk region, Russia. With regard to the data of molecular genetic analysis of the ITS region sequence, we selected the BR2-1 isolate based on its morphophysiological traits, which was assigned to the genus Leptodophora. Representatives of this genus typically enter into symbiotic relationships with heathers to form ericoid mycorrhizae. We studied the effect of strain BR2-1 on the development of microclones of the highbush blueberry var. Nord blue during their in vitro adaptation and showed its beneficial effect on growth and shoot formation in young plants. Experiments performed using submerged and solid-state methods showed that the most optimal method for commercial production of BR2-1 is cultivation on grain sterilized by boiling, followed by spore washing. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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12 pages, 3657 KiB

Open AccessArticle

Induced Expression of CYP51a and HK1 Genes Associated with Penconazole and Fludioxonil Resistance in the Potato Pathogen Fusarium oxysporum

by Yaw A. Akosah, Zarina S. Kostennikova, Marat T. Lutfullin, Guzel F. Lutfullina, Daniel M. Afordoanyi, Semyon G. Vologin and Ayslu M. Mardanova

Microorganisms 2023, 11(5), 1257; https://doi.org/10.3390/microorganisms11051257 - 10 May 2023

Cited by 4 | Viewed by 1346

Abstract

Preventing antifungal resistance development and identifying pathogens with high, medium, and low risk of resistance development to a particular fungicide or fungicide class is crucial in the fight against phytopathogens. We characterized the sensitivity of potato wilt-associated Fusarium oxysporum isolates to fludioxonil and [...] Read more.

Preventing antifungal resistance development and identifying pathogens with high, medium, and low risk of resistance development to a particular fungicide or fungicide class is crucial in the fight against phytopathogens. We characterized the sensitivity of potato wilt-associated Fusarium oxysporum isolates to fludioxonil and penconazole and assessed the effect of these fungicides on the expression of fungal sterol-14-α-demethylase (CYP51a) and histidine kinase (HK1) genes. Penconazole stunted the growth of F. oxysporum strains at all concentrations used. While all isolates were susceptible to this fungicide, concentrations of up to 1.0 μg/mL were insufficient to cause a 50% inhibition. At low concentrations (0.63 and 1.25 μg/mL), fludioxonil stimulated growth in F. oxysporum. With an increase in the concentration of fludioxonil, only one strain (F. oxysporum S95) exhibited moderate sensitivity to the fungicide. Interaction of F. oxysporum with penconazole and fludioxonil leads to respective elevated expressions of the CYP51a and HK1 genes, which upsurge with increasing concentration of the fungicides. The data obtained indicate that fludioxonil may no longer be suitable for potato protection and its continuous use could only lead to an increased resistance with time. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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15 pages, 322 KiB

Open AccessArticle

Synergy between Rhizobial Co-Microsymbionts Leads to an Increase in the Efficiency of Plant–Microbe Interactions

by Vera Safronova, Anna Sazanova, Andrey Belimov, Polina Guro, Irina Kuznetsova, Denis Karlov, Elizaveta Chirak, Oleg Yuzikhin, Alla Verkhozina, Alexey Afonin and Igor Tikhonovich

Microorganisms 2023, 11(5), 1206; https://doi.org/10.3390/microorganisms11051206 - 04 May 2023

Cited by 4 | Viewed by 1436

Abstract

Combined inoculation of legumes with rhizobia and plant growth-promoting rhizobacteria or endophytes is a known technique for increasing the efficiency of nitrogen-fixing symbiosis and plant productivity. The aim of this work was to expand knowledge about the synergistic effects between commercial rhizobia of [...] Read more.

Combined inoculation of legumes with rhizobia and plant growth-promoting rhizobacteria or endophytes is a known technique for increasing the efficiency of nitrogen-fixing symbiosis and plant productivity. The aim of this work was to expand knowledge about the synergistic effects between commercial rhizobia of pasture legumes and root nodule bacteria of relict legume species. Pot experiments were performed on common vetch (Vicia sativa L.) and red clover (Trifolium pratense L.) co-inoculated with the participation of the corresponding commercial rhizobial strains (R. leguminosarum bv. viciae RCAM0626 and R. leguminosarum bv. trifolii RCAM1365) and seven strains isolated from nodules of relict legumes inhabiting the Baikal Lake region and the Altai Republic: Oxytropis popoviana, Astragalus chorinensis, O. tragacanthoides and Vicia costata. The inoculation of plants with combinations of strains (commercial strain plus the isolate from relict legume) had a different effect on symbiosis depending on the plant species: the increase in the number of nodules was mainly observed on vetch, whereas increased acetylene reduction activity was evident on clover. It was shown that the relict isolates differ significantly in the set of genes related to different genetic systems that affect plant–microbe interactions. At the same time, they had additional genes that are involved in the formation of symbiosis and determine its effectiveness, but are absent in the used commercial strains: symbiotic genes fix, nif, nod, noe and nol, as well as genes associated with the hormonal status of the plant and the processes of symbiogenesis (acdRS, genes for gibberellins and auxins biosynthesis, genes of T3SS, T4SS and T6SS secretion systems). It can be expected that the accumulation of knowledge about microbial synergy on the example of the joint use of commercial and relict rhizobia will allow in the future the development of methods for the targeted selection of co-microsymbionts to increase the efficiency of agricultural legume–rhizobia systems. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

18 pages, 2497 KiB

Open AccessArticle

Phosphate Solubilization and Plant Growth Promotion by Pantoea brenneri Soil Isolates

by Aliya Suleimanova, Daria Bulmakova, Lidiya Sokolnikova, Evgenia Egorova, Daria Itkina, Olga Kuzminova, Albina Gizatullina and Margarita Sharipova

Microorganisms 2023, 11(5), 1136; https://doi.org/10.3390/microorganisms11051136 - 27 Apr 2023

Cited by 3 | Viewed by 2213

Abstract

Phosphate solubilizing microorganisms (PSMs) in soil have been shown to reduce mineral phosphate fertilizer supplementation and promote plant growth. Nevertheless, only several P-solubilizing microorganisms capable of solubilizing both organic and mineral sources of soil phosphorus have been identified up to now. The aim [...] Read more.

Phosphate solubilizing microorganisms (PSMs) in soil have been shown to reduce mineral phosphate fertilizer supplementation and promote plant growth. Nevertheless, only several P-solubilizing microorganisms capable of solubilizing both organic and mineral sources of soil phosphorus have been identified up to now. The aim of this study was to evaluate the inorganic soil phosphate solubilizing activity of phytate-hydrolyzing Pantoea brenneri soil isolates. We showed that the strains efficiently solubilize a variety of inorganic phosphates. We optimized the media composition and culturing conditions to improve the solubilization efficiency of the strains and investigated the mechanisms of their phosphate solubilization. Through HPLC analysis, it was determined that P. brenneri produce oxalic, malic, formic, malonic, lactic, maleic, acetic, and citric acids as well as acid and alkaline phosphatases while growing on insoluble phosphate sources. Finally, we analyzed the influence of P. brenneri strains with multiple PGP-treats on plant growth in greenhouse experiments and showed their ability to promote growth of potato. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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13 pages, 2270 KiB

Open AccessArticle

Exploring Bacterial and Fungal Biodiversity in Eight Mediterranean Olive Orchards (Olea europaea L.) in Tunisia

by Houda Gharsallah, Ines Ksentini, Olfa Frikha-Gargouri, Karama Hadj Taieb, Haifa Ben Gharsa, Christina Schuster, Amel Chatti-kolsi, Mohamed Ali Triki, Mohieddine Ksantini and Andreas Leclerque

Microorganisms 2023, 11(4), 1086; https://doi.org/10.3390/microorganisms11041086 - 21 Apr 2023

Cited by 2 | Viewed by 1645

Abstract

A wide array of bacteria and fungi are known for their association with pests that impact the health of the olive tree. The latter presents the most economically important cultivation in Tunisia. The microbial diversity associated with olive orchards in Tunisia remains unknown [...] Read more.

A wide array of bacteria and fungi are known for their association with pests that impact the health of the olive tree. The latter presents the most economically important cultivation in Tunisia. The microbial diversity associated with olive orchards in Tunisia remains unknown and undetermined. This study investigated microbial diversity to elucidate the microbial interactions that lead to olive disease, and the bio-prospects for potential microbial biocontrol agents associated with insect pests of economic relevance for olive cultivation in the Mediterranean area. Bacterial and fungal isolation was made from soil and olive tree pests. A total of 215 bacterial and fungal strains were randomly isolated from eight different biotopes situated in Sfax (Tunisia), with different management practices. 16S rRNA and ITS gene sequencing were used to identify the microbial community. The majority of the isolated bacteria, Staphylococcus, Bacillus, Alcaligenes, and Providencia, are typical of the olive ecosystem and the most common fungi are Penicillium, Aspergillus, and Cladosporium. The different olive orchards depicted distinct communities, and exhibited dissimilar amounts of bacteria and fungi with distinct ecological functions that could be considered as promising resources in biological control. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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17 pages, 23005 KiB

Open AccessArticle

Strain Streptomyces sp. P-56 Produces Nonactin and Possesses Insecticidal, Acaricidal, Antimicrobial and Plant Growth-Promoting Traits

by Irina Boykova, Oleg Yuzikhin, Irina Novikova, Pavel Ulianich, Igor Eliseev, Alexander Shaposhnikov, Alexander Yakimov and Andrey Belimov

Microorganisms 2023, 11(3), 764; https://doi.org/10.3390/microorganisms11030764 - 16 Mar 2023

Cited by 5 | Viewed by 1927

Abstract

Streptomycetes produce a huge variety of bioactive metabolites, including antibiotics, enzyme inhibitors, pesticides and herbicides, which offer promise for applications in agriculture as plant protection and plant growth-promoting products. The aim of this report was to characterize the biological activities of strain Streptomyces [...] Read more.

Streptomycetes produce a huge variety of bioactive metabolites, including antibiotics, enzyme inhibitors, pesticides and herbicides, which offer promise for applications in agriculture as plant protection and plant growth-promoting products. The aim of this report was to characterize the biological activities of strain Streptomyces sp. P-56, previously isolated from soil as an insecticidal bacterium. The metabolic complex was obtained from liquid culture of Streptomyces sp. P-56 as dried ethanol extract (DEE) and possessed insecticidal activity against vetch aphid (Medoura viciae Buckt.), cotton aphid (Aphis gossypii Glov.), green peach aphid (Myzus persicae Sulz.), pea aphid (Acyrthosiphon pisum Harr.) and crescent-marked lily aphid (Neomyzus circumflexus Buckt.), as well as two-spotted spider mite (Tetranychus urticae). Insecticidal activity was associated with production of nonactin, which was purified and identified using HPLC-MS and crystallographic techniques. Strain Streptomyces sp. P-56 also showed antibacterial and antifungal activity against various phytopathogenic bacteria and fungi (mostly for Clavibacfer michiganense, Alternaria solani and Sclerotinia libertiana), and possessed a set of plant growth-promoting traits, such as auxin production, ACC deaminase and phosphate solubilization. The possibilities for using this strain as a biopesticide producer and/or biocontrol and a plant growth-promoting microorganism are discussed. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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15 pages, 1921 KiB

Open AccessArticle

Effects on Pseudomonas plecoglossicida 2,4-D and Humic Substances on the Growth, Pigment Indices and Concentration of Hormones in Wheat Seedlings Grown under Water Deficit

by Arina Feoktistova, Maxim Timergalin, Sergey Chetverikov, Aleksey Nazarov and Guzel Kudoyarova

Microorganisms 2023, 11(3), 549; https://doi.org/10.3390/microorganisms11030549 - 21 Feb 2023

Cited by 4 | Viewed by 1150

Abstract

The search for ways to increase plant productivity in drought conditions is of fundamental importance, since soil moisture deficiency is widespread and leads to critical crop losses. The aim of this study was to identify the effects of plant growth-promoting bacteria and humic [...] Read more.

The search for ways to increase plant productivity in drought conditions is of fundamental importance, since soil moisture deficiency is widespread and leads to critical crop losses. The aim of this study was to identify the effects of plant growth-promoting bacteria and humic substances on the growth, chlorophyll, flavonoids, nitrogen balance index, and concentration of cytokinins and abscisic acids in wheat plants grown in the laboratory under conditions of water deficit. An increase in the accumulation of plant mass was shown during the treatment of wheat plants with Pseudomonas plecoglossicida 2,4-D and humic substances in these conditions. It has been shown that stimulating plant growth is associated with increased root growth, which leads to an increase in the nitrogen balance index, chlorophyll, and flavonoid concentrations in treated plants. The detected increase in the concentration of chlorophyll in plants treated with P. plecoglossicida 2,4-D correlated with a decrease in the concentration of abscisic acid in plant shoots and, in plants treated with humates, with an increase in the concentration of cytokinins in shoots. The higher efficiency of treating plants with a combination of bacteria and humic substances than with any of them individually may be associated with the additive effect of these treatments on the hormonal balance. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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20 pages, 2639 KiB

Open AccessArticle

Partial Substitution of Urea with Biochar Induced Improvements in Soil Enzymes Activity, Ammonia-Nitrite Oxidizers, and Nitrogen Uptake in the Double-Cropping Rice System

by Saif Ullah, Izhar Ali, Mei Yang, Quan Zhao, Anas Iqbal, Xiaoyan Wu, Shakeel Ahmad, Ihsan Muhammad, Abdullah Khan, Muhammad Adnan, Pengli Yuan and Ligeng Jiang

Microorganisms 2023, 11(2), 527; https://doi.org/10.3390/microorganisms11020527 - 19 Feb 2023

Cited by 6 | Viewed by 1729

Abstract

Biochar is an important soil amendment that can enhance the biological properties of soil, as well as nitrogen (N) uptake and utilization in N-fertilized crops. However, few studies have characterized the effects of urea and biochar application on soil biochemical traits and its [...] Read more.

Biochar is an important soil amendment that can enhance the biological properties of soil, as well as nitrogen (N) uptake and utilization in N-fertilized crops. However, few studies have characterized the effects of urea and biochar application on soil biochemical traits and its effect on paddy rice. Therefore, a field trial was conducted in the early and late seasons of 2020 in a randomized complete block design with two N levels (135 and 180 kg ha⁻¹) and four levels of biochar (0, 10, 20, and 30 t ha⁻¹). The treatment combinations were as follows: 135 kg N ha⁻¹ + 0 t B ha⁻¹ (T1), 135 kg N ha⁻¹ + 10 t B ha⁻¹ (T2), 135 kg N ha⁻¹ + 20 t B ha⁻¹ (T3), 135 kg N ha⁻¹ + 30 t B ha⁻¹ (T4), 180 kg N ha⁻¹ + 0 t B ha⁻¹ (T5), 180 kg N ha⁻¹ + 10 t B ha⁻¹ (T6), 180 kg N ha⁻¹ + 20 t B ha⁻¹ (T7) and 180 kg N ha⁻¹ + 30 t B ha⁻¹ (T8). The results showed that soil amended with biochar had higher soil pH, soil organic carbon content, total nitrogen content, and mineral nitrogen (NH₄⁺-N and NO₃⁻-N) than soil that had not been amended with biochar. In both seasons, the 20 t ha⁻¹ and 30 t ha⁻¹ biochar treatments had the highest an average concentrations of NO₃^–-N (10.54 mg kg⁻¹ and 10.25 mg kg⁻¹, respectively). In comparison to soil that had not been treated with biochar, the average activity of the enzymes urease, polyphenol oxidase, dehydrogenase, and chitinase was, respectively, 25.28%, 14.13%, 67.76%, and 22.26% greater; however, the activity of the enzyme catalase was 15.06% lower in both seasons. Application of biochar considerably increased the abundance of ammonia-oxidizing bacteria (AOB), which was 48% greater on average in biochar-amended soil than in unamended soil. However, there were no significant variations in the abundances of ammonia-oxidizing archaea (AOA) or nitrite-oxidizing bacteria (NOB) across treatments. In comparison to soil that had not been treated with biochar, the average N content was 24.46%, 20.47%, and 19.08% higher in the stem, leaves, and panicles, respectively. In general, adding biochar at a rate of 20 to 30 t ha⁻¹ with low-dose urea (135 kg N ha⁻¹) is a beneficial technique for improving the nutrient balance and biological processes of soil, as well as the N uptake and grain yield of rice plants. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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14 pages, 3839 KiB

Open AccessArticle

PeVL1 Novel Elicitor Protein, from Verticillium lecanii 2, Enhances Systemic Resistance against Rice Leaf Roller (Marasmia ruralis Wlk.) in Rice (Oryza sativa L.)

by Khadija Javed, Yong Wang and Humayun Javed

Microorganisms 2023, 11(2), 317; https://doi.org/10.3390/microorganisms11020317 - 26 Jan 2023

Cited by 2 | Viewed by 1313

Abstract

The hazardous pest known as rice leaf roller (Marasmia ruralis Wlk.) (Lepidoptera: Pyralidae), which undermines rice (Oryza sativa L.) output globally, folds the leaves of the rice plant. Protein elicitors are thought to be biological elements that causes the rice to [...] Read more.

The hazardous pest known as rice leaf roller (Marasmia ruralis Wlk.) (Lepidoptera: Pyralidae), which undermines rice (Oryza sativa L.) output globally, folds the leaves of the rice plant. Protein elicitors are thought to be biological elements that causes the rice to become resistant to herbivores. The potential for biocontrol of the emerging elicitor protein evaluated from Verticillium lecanii 2 (PeVL1) was evaluated against M. ruralis. To assess the impact of PeVL1 on immature development, survival, and lifetime, four different PeVL1 concentrations were allocated. Electrical penetration graphs (EPGs) against M. ruralis were used to evaluate adult reproductive efficiency and the interaction between the pest and the pathogen. Furthermore, the characterization of active substances in PeVL1 with multi-acting entomopathogenic effects looked into the direct interactions of PeVL1 with temperature and climatic change in rice (O. sativa) plants. PeVL1 treatments reduced the population increase of second and third generation M. ruralis compared to controls. In a test of host selection, M. ruralis colonized control plants more quickly than PeVL1-treated O. sativa plants. PeVL1 concentrations prolonged the M. ruralis larval stage. Similar to fecundity, PeVL1-treated seedlings produced fewer offspring than control seedlings. On PeVL1-treated leaves, trichomes and wax production created an unfavorable habitat for M. ruralis. PeVL1 changed the surface structure of the leaves, which inhibited colonization and decreased M. ruralis reproduction. The activation of pathways was another aspect of systemic defense activities including jasmonic acid (JA), salicylic acid (SA), and ethylene (ET). Based on these results against M. ruralis, the use of PeVL1 in the agroecosystem with integrated pest management and biocontrol seems appropriate. Our research provides a novel insight into a cutting-edge biocontrol method utilizing V. lecanii 2. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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15 pages, 2902 KiB

Open AccessBrief Report

New Pseudomonas Bacterial Strains: Biological Activity and Characteristic Properties of Metabolites

by Tatiana M. Sidorova, Natalia S. Tomashevich, Valeria V. Allahverdyan, Boris S. Tupertsev, Yuri I. Kostyukevich and Anzhela M. Asaturova

Microorganisms 2023, 11(8), 1943; https://doi.org/10.3390/microorganisms11081943 - 29 Jul 2023

Cited by 1 | Viewed by 840

Abstract

This paper investigates the antagonistic and plant growth promotion activity of the new indigenous bacteria antagonist strains P. chlororaphis BZR 245-F and Pseudomonas sp. BZR 523-2. It was found that on the 10th day of cultivation, BZR 245-F and BZR 523-2 exhibit an [...] Read more.

This paper investigates the antagonistic and plant growth promotion activity of the new indigenous bacteria antagonist strains P. chlororaphis BZR 245-F and Pseudomonas sp. BZR 523-2. It was found that on the 10th day of cultivation, BZR 245-F and BZR 523-2 exhibit an antagonistic activity against F. graminearum at the level of 59.6% and 15.1% and against F. oxysporum var. orthoceras at the level of 50.2% and 8.9%, respectively. Furthermore, the BZR 523-2 strain stimulated the growth of winter wheat seedlings more actively than the BZR 245-F strain. When processing seeds of winter wheat, Pseudomonas sp. BZR 523-2 indicators were higher than in the control: plant height increased by 10.3%, and root length increased by 18.6%. The complex characteristic properties of the metabolite were studied by bioautography and HPLC-MS. Bioautography proved the antifungal activity of phenazine nature compounds synthesized by the new bacterial strains. We qualitatively and quantitatively analyzed them by HPLC-MS analysis of the strain sample metabolites. In the BZR 245-F sample, we found more phenazine compounds of various types. Their total phenazine concentration in the BZR 245-F was more than five times greater than in the BZR 523-2. We defined crucial differences in the quantitative content of the other metabolites. Despite the difference between new indigenous bacteria antagonist strains, they can be used as producers of effective biopesticides for sustainable agriculture management. Full article

(This article belongs to the Special Issue Advances in Microbial and Plant Biotechnology)

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