Potential microbes from medicinal plants against Colletotrichum gloeosporioides causing anthracnose in greater yam (Dioscorea alata L.)

Abstract

Anthracnose, caused by Colletotrichum gloeosporioides is one of the most ruinous diseases affecting greater yam crops globally. Number of biocontrol agents are available now for disease management. This paper outlines the results of series of experiments and assays used for the isolation and screening of endophytes from medicinal plants against C. gloeosporioides and the investigation on the impact of potential endophytes on growth promotion and management of the disease. Present study records Bacillus licheniformis as a biocontrol agent for managing greater yam anthracnose and first report of its kind. Molecular characterization of the pathogen was carried out using universal, genus and species specific primers viz. ITS1 and ITS4; Col F and Col R; CgF1 and CgR1. Among fungal and bacterial endophytes, B. amyloliquefaciens (CTCRI-EB.3) and B. licheniformis (CTCRI-EB.12) were the finest (with an antifungal index of 84.8 ± 4.3 % / 85.7 ± 4.2 % and 82.9 ± 2.05 % / 85 ± 3.8% against the pathogen isolates Cg.S4.7 and Cg.23 respectively). Endophytes were screened for various growth promotion traits, among them B. licheniformis (CTCRI-EB.12) was unrivalled with distinguishable response to plant growth promotion traits. Results of pot trial also manifest that B. licheniformis (CTCRI-EB.12) is a promising plant growth promoting as well as a biocontrol agent.