Pantnagar Journal of Research

Abstract

The rhizosphere microbiome plays a vital role in enhancing plant health, productivity and resilience under diverse climatic stress conditions. In the present study, 52 isolates of bacteria were obtained from the rhizosphere of four Chickpea (Cicer arietinum L.) genotypes and thoroughly screened for plant growth-promoting (PGP) traits, biochemical characteristics, and multi-stress tolerance. A stepwise screening strategy was employed, in which preliminary qualitative screenings of PGP characteristics narrowed down to the selection of 16 active isolates testing positive for all the examined traits. These were then subjected to biochemical characterization, yielding seven isolates that consistently demonstrated the varying metabolic activities (viz., Catalase, Cellulase, Urease, MR-VP, Oxidase, Amylase, Caseinase, Gelatinase and Citrate utilization). Multi-stress tolerance screening revealed three extremely stress resistant strains i.e., PG5-4, PG5-12 and PG186-35, that showed admirable adaptive behaviours towards salinity, drought, temperature and pH stresses. To determine the trait-isolates correlations, Multiple Correspondence Analysis (MCA) was utilized at every selection step, attaining robust statistical confirmation of functionally proficient bacterial strains. This trait-based, multivariate approach not only streamlined the selection process but also facilitated the formulation of ecologically effective PGPR biofertilizers for sustainable agriculture. Thus, the research proposes that the above strains have substantial potential for the development of a climate-smart PGPR consortium biofertilizer, particularly suited for legume-based cropping system under very adverse environmental conditions.