EXPLORING NATURAL COMBINATION FOR IDENTIFICATION OF UPREGULATED NITROGEN FIXING BACTERIA IN GLYCINE MAX: AN IN VIVO, IN VITRO AND IN SILICO APPROACH

Abstract

Understanding the concept of symbiosis in a more localized natural selective way and optimizing for the yielding advantages of confined geography is the prime objective of the study. Precisely the aim is to isolate and identify crop specific Rhizobium strains for Glycine max using physical, biochemical and in silico techniques from Bhadrachalam forest lands. Randomly collected soil samples from 45 different locations across Bhadrachalam forest were sown with soybean in triplets. The basic parameters like Nitrogen, Phosphorous, Potassium (NPK) and levels of micronutrients for all the soil samples were identified to be similar. Out of 45 samples in triplets, top five growth supporting soils were taken for further investigation. Organisms from the root nodules of these five plants were screened and pure cultures were maintained. Log phase cultures in broth form were inoculated on the seeds sown in sterile soils with respective controls. Tremendous improvement in the growth parameters were observed in results when compared with controls. The polyphasic analysis discovered that the contributing organisms were Bradyrhizobium japonicum, Bradyrhizobium paxllaeri, Bradyrhizobium canariense, Sinorhizobium xinjiangense, Bradyrhizobium betae sp. Pure forms of these Rhizobial species have shown elevated rate of plant growth in in vitro fallowed by field experiments in low vegetative agriculture soils of the same geography. Out of these five species the Bradyrhizobium japonicum, which was the best plant growth supporting for Glycine max has been studies further to explore the Nif genes responsible for plant growth and Nitrogen fixation. The in-silico analysis of Nif A protein revealed the underlying precursors of indole acetic acid (IAA) production and nitrogenase activity. This novel method of soil selection may be adopted for easy identification of Rhizobial species, specific for not only for Glycine max but also for various other legume crops from respective geographies