Isolation and biochemical characterization of endophytic bacterium Gluconacetobacter diazotrophocusfrom native sugarcane cultivar of middle Gangetic plains of India

Abstract

Abstract Nitrogenous fertilizer is one of the dominating fertilizers, having indirect negative effect on soil health. The concept of nitrogen fixation through endophytic bacterium has been gaining popularity among farming as well as scientific community. Sugarcane which is known as high nitrogen input crop, so here its supplementation plays very promising role through endophytic. So the alternative option of this fertilizer is Gluconacetobacter. This bacterium has the plant growth promoting capacity by production of phytohormones such as auxins and gibberellins. The present study is on the isolation, biochemical characterization and screening of endophytic bacterium, was isolated from different sugarcane cultivar (roots, stem and leaf). Total 115 isolates screened, out of which 15 efficient isolates were selected based on production of growth promoting hormones. An isolate from sugarcane cultivar CoP-9301, GdS08S fixed highest amount of nitrogen i.e., 153μg of N/mg of Carbon used maximum concentration of Indole acetic acid (7.58μg/ml) while isolate GdS15S produced highest concentration of Gibberellic acid (8.19μg/25ml) which was isolated from stem part of sugarcane cultiar Co-0238. The isolate GdS07R showed highest diameter () of phosphorus and zinc solubilization zone i.e. 4.22 cm and 4.52 cm respectively. The G. diazotrophicus is found within the plant tissue, the biosynthesis of IAA and GA suggests that the bacteria could promote rooting, cell elongation and improve sugarcane growth by direct effects on metabolic processes, in addition to their role in N fixation. The best 15 screened isolate have been tested for production of organic acid (Tartaric, Fumaric, Malonic, Gluconic, Citric, and Lactic) and titratable acidity. Our results showed the importance of endophytic bacterium Gluconacetobacter diazotrophocusisolated from native sugarcane cultivars in flourishing microbial communities under intensive sugarcane cultivation system which may be act as key factor in development of more sustainable practices to feed a burgeoning population of middle gangetic plains of India. The isolated endophytic bacterium is a nitrogen fixing bacterium found in monocotyledon sugarcane plants, which actively fixes atmosphere nitrogen and provides significant amounts of nitrogen to growing crops.