Diazotrophic endophytic bacterium Alcaligenes sp. KA31 and its role in promoting the growth of wheat (Triticum aestivum L.) under saline conditions

Abstract

Intensification of food production with an increasing world population, to achieve food security has become one of the major agricultural challenges for a sustainable future. Salinity is the second most abundant threat after drought which causes disturbance in the symbiotic performance of plants and increases their susceptibility to detrimental soil-borne pathogens. In the present study, endophytic diazotroph KA31 isolated from roots of wheat plant was characterized and identified as Alcaligenes faecalis . The bacterial endophytic isolate produced indole acetic acid (IAA), and siderophore along with the potential to solubilize phosphorous (P). KA31 was also able to fix nitrogen (N) as evaluated through acetylene reduction assay and nifH -PCR assay. Recolonization ability of A. faecalis in the wheat seedlings was studied under laboratory conditions and it was demonstrated that KA31 was able to establish an endophytic association with the host plant. Furthermore, in the pot experimental study, A. faecalis KA31 significantly improved the growth parameters of wheat plants under saline conditions as compared to untreated control plants. Presumably this is the first study that reports A. faecalis as salt tolerant diazotrophic plant growth promoting endophyte (PGPE) and overall the work depicts that novel bioformulations developed using them can be effective for wheat crops grown in saline soils.