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1.
Heliyon ; 10(15): e35430, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39170238

RESUMO

Rhizobacteria play a crucial role in plant health by providing natural antagonism against soil-borne fungi. The use of rhizobacteria has been viewed as an alternative to the use of chemicals that could be useful for the integrated management of plant diseases and also increase yield in an environmentally friendly manner. However, there is limited understanding of the specific mechanisms by which rhizobacteria inhibit these pathogens and the diversity of rhizobacterial species involved. This study aims to isolate, identify, and characterize rhizobacteria with antagonistic activities against soil-borne fungi. Laboratory tests were carried out on isolated rhizobacteria to evaluate their inhibitory activity against Rhizoctonia solani, Pythium aphanidermatum and Macrophomina phaseolina. The selected bacteria were identified using the Vitek 2 compact system and 16S rRNA genes. Experiments were carried out to evaluate the plant growth promotion and biocontrol ability of these selected isolates. Out of 324 rhizobacteria isolates obtained from various plant species, twelve were chosen due to their strong (>50 %) wide-ranging antifungal activity against three significant phytopathogenic fungi species. According to the identification results, they belong to the following species: Aeribacillus pallidus ECC4, Alloiococcus otitis BRE6, Aneurinibacillus thermoaerophilus ECL1, A. thermoaerophilus SDV1, Bacillus halotolerans DMC8, B. megaterium SKE2, B. megaterium TNK1, B. subtilis NAS1, Enterobacter cloacae complex BZD3, Leclercia adecarboxylata DKS3, Paenibacillus polymyxa TRS4, and Staphylococcus lentus BZD2. Eleven isolates produced protease, six isolates produced chitinase, and seven isolates were highly effective in producing hydrogen cyanide. Ten isolates could fix nitrogen, while all isolates could produce potassium, indole-3-acetic acid, siderophore, and ammonia. These findings enhance our understanding of rhizobacterial biodiversity and their potential as biocontrol agents in sustainable agriculture.

2.
Planta ; 260(4): 79, 2024 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-39182196

RESUMO

MAIN CONCLUSION: Microbacterium strain SRS2 promotes growth and induces salt stress resistance in Arabidopsis and MicroTom in various growth substrates via the induction of the ABA pathway. Soil salinity reduces plant growth and development and thereby decreases the value and productivity of soils. Plant growth-promoting rhizobacteria (PGPR) have been shown to support plant growth such as in salt stress conditions. Here, Microbacterium strain SRS2, isolated from the root endosphere of tomato, was tested for its capability to help plants cope with salt stress. In a salt tolerance assay, SRS2 grew well up to medium levels of NaCl, but the growth was inhibited at high salt concentrations. SRS2 inoculation led to increased biomass of Arabidopsis and MicroTom tomato in various growth substrates, in the presence and in the absence of high NaCl concentrations. Whole-genome analysis revealed that the strain contains several genes involved in osmoregulation and reactive oxygen species (ROS) scavenging, which could potentially explain the observed growth promotion. Additionally, we also investigated via qRT-PCR, promoter::GUS and mutant analyses whether the abscisic acid (ABA)-dependent or -independent pathways for tolerance against salt stress were involved in the model plant, Arabidopsis. Especially in salt stress conditions, the plant growth-promotion effect of SRS2 was lost in aba1, abi4-102, abi3, and abi5-1 mutant lines. Furthermore, ABA genes related to salt stress in SRS2-inoculated plants were transiently upregulated compared to mock under salt stress conditions. Additionally, SRS2-inoculated ABI4::GUS and ABI5::GUS plants were slightly more activated compared to the uninoculated control under salt stress conditions. Together, these assays show that SRS2 promotes growth in normal and in salt stress conditions, the latter possibly via the induction of ABA-dependent and -independent pathways.


Assuntos
Ácido Abscísico , Arabidopsis , Microbacterium , Estresse Salino , Solanum lycopersicum , Arabidopsis/genética , Arabidopsis/microbiologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Solanum lycopersicum/microbiologia , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/genética , Solanum lycopersicum/fisiologia , Ácido Abscísico/metabolismo , Microbacterium/genética , Microbacterium/fisiologia , Tolerância ao Sal/genética , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Espécies Reativas de Oxigênio/metabolismo , Cloreto de Sódio/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos
3.
Curr Res Microb Sci ; 7: 100251, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39165409

RESUMO

The adoption of sustainable agricultural practices is increasingly imperative in addressing global food security and environmental concerns, with microbial based bio-inoculums emerging as a promising approach for nurturing soil health and fostering sustainable crop production.This review article explores the potential of microbial based bio-inoculumsor biofertilizers as a transformative approach toenhance plant disease resistance and growth. It explores the commercial prospects of biofertilizers, highlighting their role in addressing environmental concerns associated with conventional fertilizers while meeting the growing demand for eco-friendly agricultural practices. Additionally, this review discusses the future prospects of biofertilizers, emphasizing the ongoing advancements in biotechnology and formulation techniques that are expected to enhance their efficacy and applicability. Furthermore, this article provides insights into strategies for the successful acceptance of biofertilizers among farmers, including the importance of quality control, assurance, and education initiatives to raise awareness about their benefits and overcome barriers to adoption. By synthesizing the current research findings and industrial developments, this review offers valuable guidance for stakeholders seeking to exploit the potential of biofertilizers or beneficial microbes to promote soil health, ensure sustainable crop production, and addressing the challenges of modern agriculture.

4.
Plant Physiol Biochem ; 215: 109031, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39137684

RESUMO

Drought is a major abiotic stress that occurs frequently due to climate change, severely hampers agricultural production, and threatens food security. In this study, the effect of drought-tolerant PGPRs, i.e., PGPR-FS2 and PGPR-VHH4, was assessed on wheat by withholding water. The results indicate that drought-stressed wheat seedlings treated with PGPRs-FS2 and PGPR-VHH4 had a significantly higher shoot and root length, number of roots, higher chlorophyll, and antioxidant enzymatic activities of guaiacol peroxidase (GPX) compared to without PGPR treatment. The expression study of wheat genes related to tryptophan auxin-responsive (TaTAR), drought-responsive (TaWRKY10, TaWRKY51, TaDREB3, and TaDREB4) and auxin-regulated gene organ size (TaARGOS-A, TaARGOS-B, and TaARGOS-D) exhibited significantly higher expression in the PGPR-FS2 and PGPR-VHH4 treated wheat under drought as compared to without PGPR treatment. The results of this study illustrate that PGPR-FS2 and PGPR-VHH4 mitigate the drought stress in wheat and pave the way for imparting drought in wheat under water deficit conditions. Among the two PGPRs, PGPR-VHH4 more efficiently altered the root architecture to withstand drought stress.

5.
Chemosphere ; 364: 143113, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39151580

RESUMO

Cadmium (Cd) contamination in agricultural soil is a major global concern among the multitude of human health and food security. Zinc oxide nanoparticles (ZnO-NPs) and plant growth promoting rhizobacteria (PGPR) have been known to combat heavy metal toxicity in crops. Herein, the study intended to explore the interactive effect of treatments mediated by inoculation of PGPR and foliar applied ZnO-NPs to alleviate Cd induced phytotoxicity in wheat plants which is rarely investigated. For this purpose, TaEIL1 expression, morpho-physiological, and biochemical traits of wheat were examined. Our results revealed that Cd reduced growth and biomass, disrupted plant physiological and biochemical traits, and further expression patterns of TaEIL1. The foliar application of ZnO-NPs improved growth attributes, photosynthetic pigments, and gas exchange parameters in a dose-additive manner, and this effect was further amplified with a combination of PGPR. The combined application of ZnO-NPs (100 mg L-1) with PGPR considerably increased the catalase (CAT; 52.4%), peroxidase (POD; 57.4%), superoxide dismutase (SOD; 60.1%), ascorbate peroxidase (APX; 47.4%), leading to decreased malondialdehyde (MDA; 47.4%), hydrogen peroxide (H2O2; 38.2%) and electrolyte leakage (EL; 47.3%) under high Cd (20 mg kg-1) stress. Furthermore, results revealed a significant reduction in roots (56.3%), shoots (49.4%), and grains (59.4%) Cd concentration after the Combined treatment of ZnO-NPs and PGPR as compared to the control. Relative expression of TaEIL1 (two homologues) was evaluated under control (Cd 0), Cd, ZnO-NPs, PGPR, and combined treatments. Expression profiling revealed a differential expression pattern of TaEIL1 under different treatments. The expression pattern of TaEIL1 genes was upregulated under Cd stress but downregulated under combined ZnO-NPs and PGPR, revealing its crucial role in Cd stress tolerance. Inferentially, ZnO-NPs and PGPR showed significant potential to alleviate Cd toxicity in wheat by modulating the antioxidant defense system and TaEIL1 expression. By inhibiting Cd uptake, and facilitating their detoxification, this innovative approach ensures food safety and security.

6.
Front Microbiol ; 15: 1423980, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39176277

RESUMO

Saline soils pose significant challenges to global agricultural productivity, hindering crop growth and efficiency. Despite various mitigation strategies, the issue persists, underscoring the need for innovative and sustainable solutions. One promising approach involves leveraging microorganisms and their plant interactions to reclaim saline soils and bolster crop yields. This review highlights pioneering and recent advancements in utilizing multi-traits Trichoderma and Bacillus species as potent promoters of plant growth and health. It examines the multifaceted impacts of saline stress on plants and microbes, elucidating their physiological and molecular responses. Additionally, it delves into the role of ACC deaminase in mitigating plant ethylene levels by Trichoderma and Bacillus species. Although there are several studies on Trichoderma-Bacillus, much remains to be understood about their synergistic relationships and their potential as auxiliaries in the phytoremediation of saline soils, which is why this work addresses these challenges.

7.
Plants (Basel) ; 13(15)2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39124146

RESUMO

Argania spinosa is among the most important species of the Moroccan forest in terms of ecological, environmental, and socio-economic aspects. However, it faces a delicate balance between regeneration and degradation in its natural habitat. Hence, the efforts to preserve and regenerate argan forests are crucial for biodiversity, soil quality, and local livelihoods, yet they face challenges like overgrazing and climate change. Sustainable management practices, including reforestation and community engagement, are vital for mitigating degradation. Similarly, exploiting the argan tree's rhizosphere can enhance soil quality by leveraging its rich microbial diversity. This approach not only improves crop growth but also maintains ecosystem balance, ultimately benefiting both agriculture and the environment. This enrichment can be achieved by different factors: mycorrhizae, plant extracts, algae extracts, and plant growth-promoting rhizobacteria (PGPR). The benefits provided by PGPR may include increased nutrient availability, phytohormone production, shoot, root development, protection against several plant pathogens, and disease reduction. In this study, the effect of rhizobacteria isolated from the Agran rhizosphere was evaluated on germination percentage and radicle length for Argania spinosa in vitro tests, growth, collar diameter, and branching number under greenhouse conditions. One hundred and twenty (120) bacteria were isolated from the argan rhizosphere and evaluated for their capacity for phosphate solubilization and indole acetic acid production. The results showed that 52 isolates could solubilize phosphorus, with the diameters of the solubilization halos varying from 0.56 ± 0.14 to 2.9 ± 0.08 cm. Among 52 isolates, 25 were found to be positive for indole acetic acid production. These 25 isolates were first tested on maize growth to select the most performant ones. The results showed that 14 isolates from 25 tested stimulated maize growth significantly, and 3 of them by 28% (CN005, CN006, and CN009) compared to the control. Eight isolates (CN005, CN006, CN004, CN007, CN008, CN009, CN010, and CN011) that showed plant growth of more than 19% were selected to evaluate their effect on argan germination rate and radicle length and were subjected to DNA extraction and conventional Sanger sequencing. The 8 selected isolates were identified as: Brevundimonas naejangsanensis sp2, Alcaligenes faecalis, Brevundimonas naejangsanensis sp3, Brevundimonas naejangsanensis sp4, Leucobacter aridicollis sp1, Leucobacter aridicollis sp2, Brevundimonas naejangsanensis sp1, and Staphylococcus saprophyticus. The results showed that Leucobacter aridicollis sp2 significantly increased the germination rate by 95.83%, and the radicle length with a value of 2.71 cm compared to the control (1.60 cm), followed by Brevundimonas naejangsanensis sp3 and Leucobacter aridicollis sp1 (2.42 cm and 2.11 cm, respectively). Under greenhouse conditions, the results showed that the height growth increased significantly for Leucobacter aridicollis sp1 (42.07%) and Leucobacter aridicollis sp2 (39.99%). The isolates Brevundimonas naejangsanensis sp3 and Leucobacter aridicollis sp1 increased the gain of collar diameter by 41.56 and 41.21%, respectively, followed by Leucobacter aridicollis sp2 and Staphyloccocus saprophyticus (38.68 and 22.79%). Leucobacter aridicollis sp1 increased the ramification number per plant to 12 compared to the control, which had 6 ramifications per plant. The use of these isolates represents a viable alternative in sustainable agriculture by improving the germination rate and root development of the argan tree, as well as its development, while increasing the availability of nutrients in the soil and consequently improving fertilization.

8.
Plants (Basel) ; 13(15)2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39124180

RESUMO

This study aimed to isolate and characterize Pseudomonas native strains from the rhizospheric soil of Minthostachys verticillata plants to evaluate their potential as plant growth-promoting rhizobacteria (PGPR). A total of 22 bacterial isolates were obtained and subjected to various biochemical tests, as well as assessments of plant growth-promoting traits such as phosphate solubilization, hydrogen cyanide production, biocontrol properties through antibiosis, and indole acetic production. Genotypic analysis via 16S rRNA gene sequencing and phylogenetic tree construction identified the strains, with one particular strain named SM 33 showing significant growth-promoting effects on M. verticillata seedlings. This strain, SM 33, showed high similarity to Stutzerimonas stutzeri based on 16S rRNA gene sequencing and notably increased both shoot fresh weight and root dry weight of the plants. These findings underscore the potential application of native Pseudomonas strains in enhancing plant growth and health, offering promising avenues for sustainable agricultural practices.

9.
Plants (Basel) ; 13(15)2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39124194

RESUMO

Maize (Zea mays L.) is an essential commodity for global food security and the agricultural economy, particularly in regions such as San Martin, Peru. This study investigated the plant growth-promoting characteristics of native rhizobacteria isolated from maize crops in the San Martin region of Peru with the aim of identifying microorganisms with biotechnological potential. Soil and root samples were collected from maize plants in four productive zones in the region: Lamas, El Dorado, Picota, and Bellavista. The potential of twelve bacterial isolates was evaluated through traits, such as biological nitrogen fixation, indole acetic acid (IAA) production, phosphate solubilization, and siderophore production, and a completely randomized design was used for these assays. A completely randomized block design was employed to assess the effects of bacterial strains and nitrogen doses on maize seedlings. The B3, B5, and NSM3 strains, as well as maize seeds of the yellow hard 'Advanta 9139' variety, were used in this experiment. Two of these isolates, B5 and NSM3, exhibited outstanding characteristics as plant growth promoters; these strains were capable of nitrogen fixation, IAA production (35.65 and 26.94 µg mL-1, respectively), phosphate solubilization (233.91 and 193.31 µg mL-1, respectively), and siderophore production (34.05 and 89.19%, respectively). Furthermore, molecular sequencing identified the NSM3 isolate as belonging to Sporosarcina sp. NSM3 OP861656, while the B5 isolate was identified as Peribacillus sp. B5 OP861655. These strains show promising potential for future use as biofertilizers, which could promote more sustainable agricultural practices in the region.

10.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38990206

RESUMO

The complex evolutionary history of wheat has shaped its associated root microbial community. However, consideration of impacts from agricultural intensification has been limited. This study investigated how endogenous (genome polyploidization) and exogenous (introduction of chemical fertilizers) factors have shaped beneficial rhizobacterial selection. We combined culture-independent and -dependent methods to analyze rhizobacterial community composition and its associated functions at the root-soil interface from a range of ancestral and modern wheat genotypes, grown with and without the addition of chemical fertilizer. In controlled pot experiments, fertilization and soil compartment (rhizosphere, rhizoplane) were the dominant factors shaping rhizobacterial community composition, whereas the expansion of the wheat genome from diploid to allopolyploid caused the next greatest variation. Rhizoplane-derived culturable bacterial collections tested for plant growth-promoting (PGP) traits revealed that fertilization reduced the abundance of putative plant growth-promoting rhizobacteria in allopolyploid wheats but not in wild wheat progenitors. Taxonomic classification of these isolates showed that these differences were largely driven by reduced selection of beneficial root bacteria representative of the Bacteroidota phylum in allopolyploid wheats. Furthermore, the complexity of supported beneficial bacterial populations in hexaploid wheats was greatly reduced in comparison to diploid wild wheats. We therefore propose that the selection of root-associated bacterial genera with PGP functions may be impaired by crop domestication in a fertilizer-dependent manner, a potentially crucial finding to direct future plant breeding programs to improve crop production systems in a changing environment.


Assuntos
Agricultura , Bactérias , Fertilizantes , Raízes de Plantas , Rizosfera , Microbiologia do Solo , Triticum , Triticum/microbiologia , Triticum/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Agricultura/métodos , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/crescimento & desenvolvimento , Fertilizantes/análise , Microbiota
11.
Microbiol Res ; 286: 127827, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39002396

RESUMO

Drought is a major stressor that poses significant challenges for agricultural practices. It becomes difficult to meet the global demand for food crops and fodder. Plant physiology, physico-chemistry and morphology changes in plants like decreased photosynthesis and transpiration rate, overproduction of reactive oxygen species, repressed shoot and root shoot growth and modified stress signalling pathways by drought, lead to detrimental impacts on plant development and output. Coping with drought stress requires a variety of adaptations and mitigation techniques. Crop yields could be effectively increased by employing plant growth-promoting rhizobacteria (PGPR), which operate through many mechanisms. These vital microbes colonise the rhizosphere of crops and promote drought resistance by producing exopolysaccharides (EPS), 1-aminocyclopropane-1-carboxylate (ACC) deaminase and phytohormones including volatile compounds. The upregulation or downregulation of stress-responsive genes causes changes in root architecture due to acquiring drought resistance. Further, PGPR induces osmolyte and antioxidant accumulation. Another key feature of microbial communities associated with crops includes induced systemic tolerance and the production of free radical-scavenging enzymes. This review is focused on detailing the role of PGPR in assisting plants to adapt to drought stress.


Assuntos
Agricultura , Produtos Agrícolas , Secas , Desenvolvimento Vegetal , Reguladores de Crescimento de Plantas , Raízes de Plantas , Rizosfera , Microbiologia do Solo , Estresse Fisiológico , Produtos Agrícolas/microbiologia , Produtos Agrícolas/crescimento & desenvolvimento , Agricultura/métodos , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Bactérias/genética , Bactérias/metabolismo , Carbono-Carbono Liases/metabolismo , Carbono-Carbono Liases/genética
12.
PeerJ ; 12: e17725, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39006027

RESUMO

Background: Tomato, a fruit with a high vitamin content, is popular for consumption and economically important in Thailand. However, in the past year, the extensive usage of chemicals has significantly decreased tomato yields. Plant Growth-Promoting Rhizobacteria (PGPR) is an alternative that can help improve tomato production system growth and yield quality while using fewer chemicals. The present study aimed to determine whether endophytic actinomycetes promote growth and fruit quality of tomato (Solanum lycopersicum). Methods: The experiment was conducted in a net-houses at the Center for Agricultural Resource System Research, Faculty of Agriculture, Chiang Mai University, Chiang Mai province, Thailand. The randomized completely block design (RCBD) was carried out for four treatments with three replications, which was control, inoculation with TGsR-03-04, TGsL-02-05 and TGsR-03-04 with TGsL-02-05 in tomato plant. Isolated Actinomycetes spp. of each treatment was then inoculated into the root zone of tomato seedlings and analyzed by Scanning Electron Microscopy (SEM). The height of tomato plants was measured at 14, 28, 56, and 112 days after transplanting. Final yield and yield quality of tomato was assessed at the maturity phase. Results: The SEM result illustrated that the roots of tomato seedlings from all treatments were colonized by endophytic actinomycetes species. This contributed to a significant increase in plant height at 14 days after transplanting (DAT), as found in the TGsR-03-04 treatment (19.40 cm) compared to the control. Besides, all inoculated treatments enhanced tomato yield and yield quality. The highest weight per fruit (47.38 g), fruit length (52.37 mm), vitamin C content (23.30 mg 100 g-1), and lycopene content (145.92 µg g-1) were obtained by inoculation with TGsR-03-04. Moreover, the highest yield (1.47 kg plant-1) was obtained by inoculation with TGsL-02-05. There was no statistically significant difference in the number of fruits per plant, fruit width, brix, and antioxidant activity when various inoculations of endophytic actinomycetes were applied. Therefore, the use of endophytic actinomycetes in tomato cultivation may be an alternative to increase tomato yield and yield quality.


Assuntos
Actinobacteria , Frutas , Solanum lycopersicum , Solanum lycopersicum/microbiologia , Solanum lycopersicum/crescimento & desenvolvimento , Frutas/microbiologia , Frutas/crescimento & desenvolvimento , Actinobacteria/metabolismo , Tailândia , Endófitos/fisiologia
13.
J Integr Plant Biol ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967265

RESUMO

Soil salinity is a worldwide problem threatening crop yields. Some plant growth-promoting rhizobacteria (PGPR) could survive in high salt environment and assist plant adaptation to stress. Nevertheless, the genomic and metabolic features, as well as the regulatory mechanisms promoting salt tolerance in plants by these bacteria remain largely unknown. In the current work, a novel halotolerant PGPR strain, namely, Bacillus sp. strain RA can enhance tomato tolerance to salt stress. Comparative genomic analysis of strain RA with its closely related species indicated a high level of evolutionary plasticity exhibited by strain-specific genes and evolutionary constraints driven by purifying selection, which facilitated its genomic adaptation to salt-affected soils. The transcriptome further showed that strain RA could tolerate salt stress by balancing energy metabolism via the reprogramming of biosynthetic pathways. Plants exude a plethora of metabolites that can strongly influence plant fitness. The accumulation of myo-inositol in leaves under salt stress was observed, leading to the promotion of plant growth triggered by Bacillus sp. strain RA. Importantly, myo-inositol serves as a selective force in the assembly of the phyllosphere microbiome and the recruitment of plant-beneficial species. It promotes destabilizing properties in phyllosphere bacterial co-occurrence networks, but not in fungal networks. Furthermore, interdomain interactions between bacteria and fungi were strengthened by myo-inositol in response to salt stress. This work highlights the genetic adaptation of RA to salt-affected soils and its ability to impact phyllosphere microorganisms through the adjustment of myo-inositol metabolites, thereby imparting enduring resistance against salt stress in tomato.

14.
BMC Microbiol ; 24(1): 261, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39004720

RESUMO

BACKGROUND: The excessive application of chemical fertilizers in the cultivation of Astragalus mongholicus Bunge results in a reduction in the quality of the medicinal plant and compromises the sustainable productivity of the soil. PGPB inoculant is a hot topic in ecological agriculture research. In the cultivation of Astragalus mongholicus, the screened nitrogen-fixing bacteria can promote plant growth, however, whether it can promote the accumulation of main bioactive components remains unknown. In this study, mixed inoculants containing 5 strains of growth promoting bacteria (Rhizobium T16 , Sinorhizobium T21 , Bacillus J1 , Bacillus G4 and Arthrobacter J2) were used in the field experiment. The metabolic substances in the root tissues of Astragalus mongholicus were identified during the harvest period by non-targeted metabolomics method, and the differential metabolites between groups were identified by statistical analysis. Meanwhile, high-throughput sequencing was performed to analyze the changes of rhizosphere soil and endophytic microbial community structure after mixed microbial treatment. RESULTS: The results of non-targeted metabolism indicated a significant increase in the levels of 26 metabolites after treatment including 13 flavonoids, 3 saponins and 10 other components. The contents of three plant hormones (abscisic acid, salicylic acid and spermidine) also increased after treatment, which presumed to play an important role in regulating plant growth and metabolism. Studies on endosphere and rhizosphere bacterial communities showed that Rhzobiaceae, Micromonosporaceae, and Hypomicrobiaceae in endophytic, and Oxalobactereae in rhizosphere were significantly increased after treatment. These findings suggest their potential importance in plant growth promotion and secondary metabolism regulation. CONCLUSIONS: This finding provides a basis for developing nitrogen-fixing bacteria fertilizer and improving the ecological planting efficiency of Astragalus mongholicus.


Assuntos
Astrágalo , Microbiota , Raízes de Plantas , Rizosfera , Microbiologia do Solo , Raízes de Plantas/microbiologia , Raízes de Plantas/metabolismo , Astrágalo/microbiologia , Astrágalo/metabolismo , Bactérias Fixadoras de Nitrogênio/metabolismo , Bactérias Fixadoras de Nitrogênio/genética , Saponinas/metabolismo , Bactérias/metabolismo , Bactérias/classificação , Bactérias/genética , Metabolômica , Arthrobacter/metabolismo , Arthrobacter/genética , Endófitos/metabolismo , Endófitos/genética , Rhizobium/metabolismo
15.
Indian J Microbiol ; 64(2): 409-417, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39010983

RESUMO

Microbes in the rhizosphere play a significant role in the growth, development, and efficiency of plants and trees. The rhizospheric area's microbes are reliant on the soil's characteristics and the substances that the plants release. The majority of previous research on medicinal plants concentrated on their bioactive phytochemicals, but this is changing now that it is understood that a large proportion of phytotherapeutic substances are actually created by related microorganisms or through contact with their host. The roots of medicinal plants secrete a large number of secondary metabolites that determine the diversity of microbial communities in their rhizosphere. The dominant bacteria isolated from a variety of medicinal plants include various species of Bacillus, Rhizobium, Pseudomonas, Azotobacter, Burkholderia, Enterobacte, Microbacterium, Serratia, Burkholderia, and Beijerinckia. Actinobacteria also colonize the rhizosphere of medicinal plants that release low molecular weight organic solute that facilitate the solubilisation of inorganic phosphate. Root exudates of medicinal plants resist abiotic stress and accumulate in soil to produce autotoxic effects that exhibit strong obstacles to continuous cropping. Although having a vast bioresource that may be used in agriculture and modern medicine, medicinal plants' microbiomes are largely unknown. The purpose of this review is to (i) Present new insights into the plant microbiome with a focus on medicinal plants, (ii) Provide information about the components of medicinal plants derived from plants and microbes, and (iii) Discuss options for promoting plant growth and protecting plants for commercial cultivation of medicinal plants. The scientific community has paid a lot of attention to the use of rhizobacteria, particularly plant growth-promoting rhizobacteria (PGPR), as an alternative to chemical pesticides. By a variety of processes, these rhizobacteria support plant growth, manage plant pests, and foster resilience to a range of abiotic challenges. It also focuses on how PGPR inoculation affects plant growth and survival in stressful environments.

16.
Indian J Microbiol ; 64(2): 287-303, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39011023

RESUMO

Drought stress is a significant environmental challenge affecting global agriculture, leading to substantial reductions in crop yields and overall plant productivity. It induces a cascade of physiological and biochemical changes in plants, including reduced water uptake, stomatal closure, and alterations in hormonal balance, all of which contribute to impaired growth and development. Drought stress diminishes crop production by impacting crucial plant metabolic pathways. Plants possess the ability to activate or deactivate specific sets of genes, leading to changes in their physiological and morphological characteristics. This adaptive response enables plants to evade, endure, or prevent the effects of drought stress. Drought stress triggers the activation of various genes, transcription factors, and signal transduction pathways in plants. In this context, imposing plant growth-promoting rhizobacteria (PGPR) emerges as a promising strategy. PGPR, employing diverse mechanisms such as osmotic adjustments, antioxidant activity, and phytohormone production, not only ensures the plant's survival during drought conditions but also enhances its overall growth. This comprehensive review delves into the various mechanisms through which PGPR enhances drought stress resistance, offering a thorough exploration of recent molecular and omics-based approaches to unravel the role of drought-responsive genes. The manuscript encompasses a detailed mechanistic analysis, along with the development of PGPR-based drought stress management in plants.

17.
Antonie Van Leeuwenhoek ; 117(1): 92, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949726

RESUMO

Biological control is a promising approach to enhance pathogen and pest control to ensure high productivity in cash crop production. Therefore, PGPR biofertilizers are very suitable for application in the cultivation of tea plants (Camellia sinensis) and tobacco, but it is rarely reported so far. In this study, production of a consortium of three strains of PGPR were applied to tobacco and tea plants. The results demonstrated that plants treated with PGPR exhibited enhanced resistance against the bacterial pathogen Pseudomonas syringae (PstDC3000). The significant effect in improving the plant's ability to resist pathogen invasion was verified through measurements of oxygen activity, bacterial colony counts, and expression levels of resistance-related genes (NPR1, PR1, JAZ1, POD etc.). Moreover, the application of PGPR in the tea plantation showed significantly reduced population occurrences of tea green leafhoppers (Empoasca onukii Matsuda), tea thrips (Thysanoptera:Thripidae), Aleurocanthus spiniferus (Quaintanca) and alleviated anthracnose disease in tea seedlings. Therefore, PGPR biofertilizers may serve as a viable biological control method to improve tobacco and tea plant yield and quality. Our findings revealed part of the mechanism by which PGPR helped improve plant biostresses resistance, enabling better application in agricultural production.


Assuntos
Nicotiana , Controle Biológico de Vetores , Doenças das Plantas , Pseudomonas syringae , Animais , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Nicotiana/microbiologia , Pseudomonas syringae/fisiologia , Controle Biológico de Vetores/métodos , Camellia sinensis/microbiologia , Camellia sinensis/crescimento & desenvolvimento , Insetos/microbiologia , Tisanópteros/microbiologia , Resistência à Doença , Desenvolvimento Vegetal , Agentes de Controle Biológico , Hemípteros/microbiologia
18.
Microbiol Res ; 287: 127831, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39079267

RESUMO

Lead (Pb) is the 2nd known portentous hazardous substance after arsenic (As). Being highly noxious, widespread, non-biodegradable, prolonged environmental presence, and increasing accumulation, particularly in arable land, Pb pollution has become a serious global health concern requiring urgent remediation. Soil-borne, indigenous microbes from Pb-polluted sites have evolved diverse resistance strategies, involving biosorption, bioprecipitation, biomineralization, biotransformation, and efflux mechanisms, under continuous exposure to Pb in human-impacted surroundings. These strategies employ a wide range of functional bioligands to capture Pb and render it inaccessible for leaching. Recent breakthroughs in molecular technology and understanding of lead resistance mechanisms offer the potential for utilizing microbes as biological tools in environmental risk assessment. Leveraging the specific affinity and sensitivity of bacterial regulators to Pb2+ ions, numerous lead biosensors have been designed and deployed worldwide to monitor Pb bioavailability in contaminated sites, even at trace levels. Besides, the ongoing degradation of croplands due to Pb pollution poses a significant challenge to meet the escalating global food demands. The accumulation of Pb in plant tissues jeopardizes both food safety and security while severely impacting plant growth. Exploring Pb-resistant plant growth-promoting rhizobacteria (PGPR) presents a promising sustainable approach to agricultural practices. The active associations of PGPR with host plants have shown enhancements in plant biomass and stress alleviation under Pb influence. They thus serve a dual purpose for plants grown in Pb-contaminated areas. This review aims to offer a comprehensive understanding of the role played by Pb-resistant soil-borne indigenous bacteria in expediting bioremediation and improving the growth of Pb-challenged plants essential for potential field application, thus broadening prospects for future research and development.


Assuntos
Bactérias , Biodegradação Ambiental , Chumbo , Desenvolvimento Vegetal , Microbiologia do Solo , Poluentes do Solo , Chumbo/metabolismo , Chumbo/toxicidade , Poluentes do Solo/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Bactérias/efeitos dos fármacos , Plantas/microbiologia , Plantas/metabolismo , Solo/química , Estresse Fisiológico
19.
Int J Biol Macromol ; 276(Pt 1): 133800, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38996895

RESUMO

The use of beneficial microorganisms and polysaccharides for the biocontrol of plant diseases currently represents a promising tool for the management of soil-borne pathogens. Despite advancements, enhancing the efficacy and sustainability of these biocontrol methods, particularly in complex soil environments, remains a challenge. Thus, we investigated the potential of four PGPR strains encapsulated in natural alginate extracted from a brown seaweed Bifurcaria bifurcata to evaluate its biocontrol capacities against Verticillium wilt of tomato, ensuring optimal performance through a synergistic effect and innovative bacterial release. Our research demonstrated that the application of PGPR and alginate reduced disease severity and mortality rate and increased the natural defenses of tomato. Results showed that supplying alginate or the PGPR consortium at the root level s stimulates phenylalanine ammonia-lyase activity (the key enzyme of the phenylpropanoid metabolism) and the accumulation of phenolic compounds and lignin in leaves and roots. Treatment with PGPR encapsulated in alginate beads showed the best biocontrol efficiency and was accompanied by a synergistic effect reflecting a rapid, intense, and systemic induction of defense mechanisms known for their effectiveness in inducing resistance in tomato. These promising results suggest that such bioformulations could lead to innovative agricultural practices for sustainable plant protection against pathogens.


Assuntos
Alginatos , Doenças das Plantas , Solanum lycopersicum , Verticillium , Solanum lycopersicum/microbiologia , Alginatos/química , Alginatos/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Verticillium/patogenicidade , Verticillium/efeitos dos fármacos , Alga Marinha/microbiologia , Fenilalanina Amônia-Liase/metabolismo , Raízes de Plantas/microbiologia , Agentes de Controle Biológico/farmacologia
20.
PeerJ ; 12: e17578, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38948222

RESUMO

In the eastern coastal regions of Odisha, wilt caused by Fusarium oxysporum f. sp.capsici is an extremely damaging disease in chilli. This disease is very difficult to manage with chemical fungicides since it is soil-borne in nature. The natural rhizosphere soil of the chilli plant was used to isolate and test bacterial antagonists for their effectiveness and ability to promote plant growth. Out of the fifty-five isolates isolated from the rhizosphere of healthy chilli plants, five isolates, namely Iso 01, Iso 17, Iso 23, Iso 24, and Iso 32, showed their highly antagonistic activity against F. oxysporum f. sp. capsici under in vitro. In a dual culture, Iso 32 (73.3%) and Iso 24 (71.5%) caused the highest level of pathogen inhibition. In greenhouse trials, artificially inoculated chilli plants treated with Iso 32 (8.8%) and Iso 24 (10.2%) had decreased percent disease incidence (PDI), with percent disease reduction over control of 85.6% and 83.3%, respectively. Iso 32 and Iso 24 treated chilli seeds have shown higher seed vigor index of 973.7 and 948.8, respectively, as compared to untreated control 636.5. Furthermore, both the isolates significantly increased plant height as well as the fresh and dry weight of chilli plants under the rolled paper towel method. Morphological, biochemical, and molecular characterization identified Bacillus amyloliquefaciens (MH491049) as the key antagonist. This study demonstrates that rhizobacteria, specifically Iso 32 and Iso 24, can effectively protect chilli plants against Fusarium wilt while promoting overall plant development. These findings hold promise for sustainable and eco-friendly management of Fusarium wilt in chilli cultivation.


Assuntos
Fusarium , Doenças das Plantas , Rizosfera , Microbiologia do Solo , Fusarium/isolamento & purificação , Fusarium/patogenicidade , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Capsicum/microbiologia , Capsicum/crescimento & desenvolvimento , Antibiose/fisiologia , Desenvolvimento Vegetal
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