Jay Kishor Prasad

Micronutrient deficiencies have significant impacts on plant growth, grain yield and nutritional quality. Biofortification through seed biopriming can be an effective strategy in meeting the challenges of malnutrition under the changing climatic conditions. Therefore, to evaluate the effects of potent growth promoting rhizospheric microbes Enterobacter cloacae BHUSR1, Serratia marcescens BHUSR2 and Klebsiella aerogenes BHUSR3 on nutrient content of oat grains at different irrigation levels (7 and 10 days) the present work was undertaken. The experiments were conducted in field trials in a randomized complete block design, and the data were statistically analyzed using analysis of variance (ANOVA). The yield was improved significantly upto 93% after seed biopriming even when grown under drought. Improvement in macronutrients observed was upto 39.4% for potassium, 51.1% for phosphorus, while the essential micro-nutrients augmented were 50.5% zinc and 41.6% manganese. Among all the selected strains Klebsiella aerogenes BHUSR3 was found to be most effective in mobilizing phosphorous, potassium, iron, zinc, manganese under irrigated conditions. The macro and micro-nutrients biofortified under drought were bacterial dependent with no common trend observed.

In natural ecosystems, most of the micronutrients are present in forms that are inaccessible to plants or bound in organic molecules. The assimilation of nutrients by plants is assisted by millions of soil microbes that possess the ability to depolymerize or mineralize nutrients into an available form to plants. A deficiency in micronutrients can disrupt the morphological and physiological growth of plants. Accessibility to both micro and macro nutrients by utilizing microorganisms has emerged as an excellent strategy in sustainable agriculture. Microbes found in the soil-root interface have the potential to solubilize the trace element. The abundant proliferation of Plant Growth-Promoting Microorganisms (PGPMs) in the rhizosphere is advantageous for plants, as these microorganisms are widely acknowledged for their growth-promoting activities. Nevertheless, there is still a considerable amount to discover regarding the physiology and mechanisms governing the absorption, translocation, and deposition of plant micronutrients facilitated by rhizobacteria. Microbes enhance plant growth by altering hormonal signaling, inhibiting pathogens, or increasing nutrient bioavailability. Application of microbial inoculants to plants at an early stage of development enhances their performances even under stress conditions. PGPM has come up as a reliable alternative to replace the chemicals in agricultural sectors as an environment cleanup strategy. This review highlights the role of soil microbes and their mechanisms they adopt in plant nutrient mobilization and uptake.