Revitalization of bacterial endophytes and rhizobacteria for nutrients bioavailability in degraded soils to promote crop production

Mburu, Simon Wambui; Koskey, Gilbert; Njeru, Ezekiel Mugendi; Maingi, John M.

doi:10.3934/agrfood.2021029

Cited by 10 publications

(5 citation statements)

References 169 publications

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“…Organic acid are considered as an essential source of carbon and are rich in vitality. Plant growth promoting bacteria synthesize various secondary metabolites such as phytohormones and organic osmolytes that activate host plants stress management mechanisms and solubilize nutrients for easy absorption by plants [ 123 ]. Organic acid producing bacteria alleviate heat stress and enhance plant growth in soybean and tomato [ 105 , 124 , 125 ].…”

Section: Molecular Mechanism Of Action Of Microbes In Mitigating Heat...mentioning

confidence: 99%

A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants

et al. 2022

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Among abiotic stresses, heat stress is described as one of the major limiting factors of crop growth worldwide, as high temperatures elicit a series of physiological, molecular, and biochemical cascade events that ultimately result in reduced crop yield. There is growing interest among researchers in the use of beneficial microorganisms. Intricate and highly complex interactions between plants and microbes result in the alleviation of heat stress. Plant–microbe interactions are mediated by the production of phytohormones, siderophores, gene expression, osmolytes, and volatile compounds in plants. Their interaction improves antioxidant activity and accumulation of compatible osmolytes such as proline, glycine betaine, soluble sugar, and trehalose, and enriches the nutrient status of stressed plants. Therefore, this review aims to discuss the heat response of plants and to understand the mechanisms of microbe-mediated stress alleviation on a physio-molecular basis. This review indicates that microbes have a great potential to enhance the protection of plants from heat stress and enhance plant growth and yield. Owing to the metabolic diversity of microorganisms, they can be useful in mitigating heat stress in crop plants. In this regard, microorganisms do not present new threats to ecological systems. Overall, it is expected that continued research on microbe-mediated heat stress tolerance in plants will enable this technology to be used as an ecofriendly tool for sustainable agronomy.

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Section: Molecular Mechanism Of Action Of Microbes In Mitigating Heat...mentioning

confidence: 99%

A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants

et al. 2022

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“…Similar to other rhizobacteria, recovered endophytic bacteria such as Bacillus, Pseudomonas , and Serratia participate in ecosystem functions and play key roles in plant growth and development through biogeochemical cycling, nutrient solubilization, and phytohormone synthesis (Pirhadi et al., 2018; Vardharajula et al., 2017). The production of IAA, siderophore, and NH 4 + were prevalent among the endophytic bacteria (Mburu et al., 2021). The phyllosphere endophytes had higher IAA and PO 4 concentration compared with the root endophytes, which had higher NH 4 + and siderophore production.…”

Section: Discussionmentioning

confidence: 99%

16S rRNA gene‐based identification and plant growth‐promoting potential of cultivable endophytic bacteria

Raimi

Adeleke

2023

Agronomy Journal

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Endophytic bacteria play essential roles in plant growth and fitness through nitrogen fixation, nutrient solubilization, and phytohormone production. However, the plant growth-promoting (PGP) potential of endophytic microorganisms inhabiting vegetables is underexplored. Thus, this study investigated the endophytic bacteria of vegetable crops for their PGP properties using the culture-dependent technique. Recovered isolates were identified by sequencing the partial 16S rRNA gene using Sanger sequencing. The isolated endophytic bacteria belonged to 15 genera and 39 different species. Bacillus, Enterobacter, Pantoea, and Pseudomonas were the predominant genera and had high phosphate solubilization and siderophore production potential. The isolates differentially produced indole-3-acetic acid and ammonium in the range 0.14-44.48 μg mL -1 and 0.77-93.24 mg L -1 , respectively. Pseudomonas azotoformans, Stenotrophomonas maltophilia, and Serratia liquefaciens showed a high level of siderophore production, which was not significantly (p > 0.05) different across the plant and organ types. More than 21% of endophytes could produce gelatinase, protease, amylase, and cellulase, contributing to their diverse ecosystem functions. Bacterial density and species composition varied across the vegetable species, organs, and farm locations but were higher in the stems compared with other organs. However, the vegetable organ had no significant (p > 0.05) influence on the bacterial population density, except for the interaction of plant species and organs.Overall, this study provides basic knowledge about the cultivable endophytic bacterial community of vegetables and reveals diverse endophytic bacteria useful in bioinoculant formulations for improving crop productivity.

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“…The correspondence analysis indicated that soil organic compound, available P, and total N were the important factors influencing soil microbial diversity. According Mburu et al [ 26 ], plant growth promoting rhizobacteria (PGPR) mediate key soil processes involved in nitrogen, phosphorus and carbon cycling, which potentially determine correlation between environmental factors and microbial structure. Growth limiting resources available in the soil such as organic compounds in detritus influence microbial diversity by generating cellular energy, and especially for heterotrophic bacterial communities [ 59 ].…”

Section: Discussionmentioning

confidence: 99%

Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions

Mburu

Koskey

Njeru

et al. 2022

Journal of Genetic Engineering and Biotechnology

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Background Global food supply is highly dependent on field crop production that is currently severely threatened by changing climate, poor soil quality, abiotic, and biotic stresses. For instance, one of the major challenges to sustainable crop production in most developing countries is limited nitrogen in the soil. Symbiotic nitrogen fixation of legumes such as soybean (Glycine max (L.) Merril) with rhizobia plays a crucial role in supplying nitrogen sufficient to maintain good crop productivity. Characterization of indigenous bradyrhizobia is a prerequisite in the selection and development of effective bioinoculants. In view of this, bradyrhizobia were isolated from soybean nodules in four agro-climatic zones of eastern Kenya (Embu Upper Midland Zone, Embu Lower Midland Zone, Tharaka Upper Midland Zone, and Tharaka Lower Midland Zone) using two soybean varieties (SB8 and SB126). The isolates were characterized using biochemical, morphological, and genotypic approaches. DNA fingerprinting was carried out using 16S rRNA gene and restricted by enzymes HaeIII, Msp1, and EcoRI. Results Thirty-eight (38) bradyrhizobia isolates obtained from the trapping experiments were placed into nine groups based on their morphological and biochemical characteristics. Most (77%) of the isolates had characteristics of fast-grower bradyrhizobia while 23% were slow-growers. Restriction digest revealed significant (p < 0.015) variation within populations and not among the agro-climatic zones based on analysis of molecular variance. Principal coordinate analysis demonstrated sympatric speciation of indigenous bradyrhizobia isolates. Embu Upper Midland Zone bradyrhizobia isolates had the highest polymorphic loci (80%) and highest genetic diversity estimates (H’ = 0.419) compared to other agro-climatic zones. Conclusion The high diversity of bradyrhizobia isolates depicts a valuable genetic resource for selecting more effective and competitive strains to improve promiscuous soybean production at a low cost through biological nitrogen fixation.

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Revitalization of bacterial endophytes and rhizobacteria for nutrients bioavailability in degraded soils to promote crop production

Cited by 10 publications

References 169 publications

A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants

A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants

16S rRNA gene‐based identification and plant growth‐promoting potential of cultivable endophytic bacteria

Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions

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