Isolation and Characterization of Plant Growth Promoting Endophytic Diazotrophic Bacteria from Wheat Genotypes and their Influence on Plant Growth Promotion

Nitrogen (N) is an essential element for the growth and yield of wheat. Some endophytic bacteria can fix N2 from the air and convert to nitrogen compounds that can be utilized by plants. In this study, endophytic bacteria were isolated from one-month-old seedlings of 13 wheat genotypes growing without nitrogen fertilizer in the ICAR –IARI field. A total of 23 diazotrophic endophytes were isolated from 13 wheat genotypes used. Nitrogenase enzyme activities of endophytes were measured by acetylene reduction assay (ARA). Among 23 isolates, 17 isolates showed the IAA production and three isolates exhibited siderophore production ability. 13 isolated diazotrophic endophytes give clear halo zone around the colony on tricalcium phosphate containing Pikovaskaya’s agar plates. None of them exhibited HCN and ammonia production ability. Nitrogenase activity of isolates was ranged from 5 to 30 nmol C2H4/mg protein/h. Endophytes inoculation significantly increase the root length, root fresh weight and root dry weight. Likewise, endophytes inoculation also showed significant results on fresh weight and dry weight of shoot. Both the endophytes were identified as Azospirillium sp. by 16S rRNA gene sequencing.