Plant growth promoting soil microbiomes and their potential implications for agricultural and environmental sustainability

Abstract

Soil microbial diversity is very important part of ecosystem as it plays a significant role in biogeochemical cycles. Currently, health of environment has been depleted due to growing population of the world and human activities like industrialization, overexploitation of chemical based products in agriculture and urbanization. These problems are now being of major concern of the environmentalist and to fix these problems has become an emergence. Soil microbiomes have been recognized as a potent tool for the sustainable agriculture and environment. Such microbes exhibit hidden talent to overcome the environmental related problem like pollution and soil degradation. In agriculture, soil microbiomes can be used as a biofertilizers over the chemical based products. Soil microbes help in reclamation of soil fertility, alleviation of diverse abiotic stresses, and nutrients stress that help in plant growth and development. Soil microbes help plant for growth via direct mechanisms for enhancing plant growth directly in a sustainable way like solubilization of nutrients (P, K, and Zn), fixation of nitrogen and chelation of iron as well as via indirectly by controlling pathogen growth and alleviating abiotic stress. In environment, beneficial soil microbiomes help in the degradation of environment pollutants like chemical pesticides and industrial waste by enzymatic actions and biosorption techniques. Present review deals with the diversity of soil microbiomes and their role in plant growth promotion and remediation of diverse environmental pollutants for agro-environmental sustainability.

Drought adaptive microbes as bioinoculants for the horticultural crops

“…Modification of phytohormones activity in the plant is another mechanism to alleviate the drought in the horticultural crops. Plants produce different kind of phytohormones such as auxin (indole-3-acetic acid), ethylene, abscisic acid, jasmonic acid, gibberellins, and cytokinins that plays imperative role in the plant growth, development and abiotic stress tolerance ( Kaur et al., 2021b ; Tiwari et al., 2020 ). Drought tolerant microbiomes help in producing these phytohormones that cope up with water deficit conditions ( Vurukonda et al., 2016 ).…”

“…Potassium (K) is an essential nutrient in protein synthesis, glycolytic enzymes, and photosynthesis ( Kaur et al., 2021b , Kaur et al., 2021a ; Kour et al., 2020 ). It is an important osmoticum that mediates cell expansion and turgor-driven movements.…”

Microbial consortium with nitrogen fixing and mineral solubilizing attributes for growth of barley (Hordeum vulgare L.)

“…Various groups of plant associated microbial strains have been reported for improving plant growth in normal and stressed environmental conditions such as Bacillus, Pseudomonas, and Rhizobium ( Afzal et al., 2017 ), Azospirillum brasilense ( Di Salvo et al., 2018 ), Oceanobacillus ( Albdaiwi et al., 2019 ), Streptomyces laurentii ( Kour et al., 2020 ), and Pseudomonas alcaliphila ( AlAli et al., 2021 ). Microbes living freely or in association with plant's different regions (rhizospheric, epiphytic and endophytic) promotes the growth of the host via direct and indirect PGP attributes such as fixation of atmospheric nitrogen; nutrients (P, K, Zn) solubilization and mobilization; production of siderophores (Fe chelating agent), plant growth regulators (auxin, abscisic acid, cytokinin, ethylene, gibberellins, jasmonic acid), ammonia, hydrogen cyanide, 1-aminocyclopropane-1-carboxylate (ACC), hydrolytic enzymes (protease, cellulase, amylase and chitinase) and various plant growth promoting bioactive compounds secondary metabolites ( Kaur et al., 2021 ; Kour et al., 2019 ).…”

Plant growth promotion of barley (Hordeum vulgare L.) by potassium solubilizing bacteria with multifarious plant growth promoting attributes

“…The potassium solubilizing bacteria also produces amino acids, vitamins which helps in growth promotion. One possible way to alleviate deficiency of potassium is to use of a KSB that play major roles in availing the potassium minerals by Ksolubilization through diverse mechanisms like acidolysis, chelation, complexolysis, exchange reactions and organic acids production (5,6). These microbes residing in the rhizospheric region of plants are known as K-solubilizers and have the capability to augment potassium availability to plants.…”