Exopolysaccharide-Producing Rhizospheric Bacteria Enhance Yield via Promoting Wheat (Triticum aestivum L.) Growth at Early Stages
J. Prasad, Riddha Dey, Richa Raghuwanshi
Abstract
Plant-soil interactions directing plant growth are governed by chemical communications among the microorganisms, and between the plants and microbes. A study was conducted to evaluate the effects of seed biopriming with native plant-growth promoting rhizobacteria (PGPR) on growth parameters of wheat. Rhizospheric bacteria isolated from drought-exposed fields were characterized on morphological, biochemically and molecular basis and screened for PGP traits. Nine isolates were able to solubilize essential nutrients, produce plant growth hormone indole acetic acid (IAA), and most of the isolates were positive for siderophore, ammonia, hydrogen cyanide (HCN), and hydrolytic enzyme production. Considerable and varying amounts of exopolysaccharides (EPS) constituted of proteins (amide I, II, III), polysaccharides, nucleic acids and peptidoglycan were produced by few strains that helped in formation of biofilm matrix. Biopriming wheat seeds with selected bacterial isolates brought significant increase in wheat germination, growth, and yield parameters. Correlation analysis revealed that the phytohormone, phosphate solubilization and EPS-producing abilities were the most obvious PGP traits of bacteria related to the growth and yield of wheat plants. Among all the nine bacterial isolates tested, two isolates, viz. Pseudomonas azotoformans JRBHU5 and Burkholderia seminalis JRBHU6, with good colonizing abilities enhanced plant vigor at early stage thereby augmenting wheat growth.