Isolation, Characterization, and Screening of Endospore Forming Endophytic Bacteria from Cowpea [Vigna unguiculata (L.) Walp.] for Plant Growth Promotion and Abiotic Stress Mitigation
Sivapriya S. L. *
Department of Agricultural Microbiology, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, India.
Anith K. N.
Department of Agricultural Microbiology, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, India.
*Author to whom correspondence should be addressed.
Abstract
We performed isolation and characterization of endospore forming endophytic bacteria (EEB) from endorhizospheric region of healthy bush cowpea var. Bhagyalakshmi. All the EEB isolates were evaluated for their ability to produce plant growth promoting traits such as production of indole acetic acid (IAA), gibberellic acid, ammonia, ACC deaminase, volatile organic compounds and siderophore, and capacity for nitrogen fixation, and solubilization of phosphorus and potassium. Roll towel assay was used for assessing the seedling vigour index of cowpea after seed priming with the EEB isolates. Based on growth promotion and seedling vigour index, seven superior bacterial isolates were selected, and antagonistic activity against the fungal pathogens Fusarium oxysporum, Rhizoctonia solani, Colletotrichum sp., Phytophthora sp., and Pythium sp., was assayed. The isolates were pooled together to form a consortium and biopriming of cowpea seeds were done. Bioprimed seeds were tested for plant growth promotion and abiotic stress management in cowpea under protray condition. The seedlings of the bioprimed cowpea seeds showed better seedling vigour index and stress tolerance compared to hydro-primed seeds and the unprimed control. EEB isolated from the host plant could be developed as plant growth promoting bioagents.
Keywords: Bacillus spp, biopriming, seedling vigour, antagonism