Xu T, Li Y, Zeng X, Yang X, Yang Y, Yuan S, Hu X, Zeng J, Wang Z, Liu Q, Liu Y, Liao H, Tong C, Liu X, Zhu Y

J Sci Food Agric. 2016 Jun 13. doi: 10.1002/jsfa.7841. [Epub ahead of print]

Abstract

BACKGROUND:

Biocontrol is a promising strategy in the control of rice blast disease. In this study, we isolated and characterized a novel antagonist to the pathogen Magnaporthe oryzae from rice endophytic actinomycetes.

RESULTS:

Out of 482 endophytic actinomycetes isolated from rice blast infected and healthy rice, Streptomyces endus OsiSh-2, exhibited a remarkable in vitro antagonistic activity. Scanning electron microscopy observation of M.oryzae treated by OsiSh-2 revealed significant morphological alterations in hyphae. In two-year's field tests, spraying OsiSh-2 spore solution (10⁷ spores mL^-1 ) is capable of reducing rice blast disease severity by 59.64%. In addition, both fermentation broth of OsiSh-2 and its cell-free filtrates could inhibit growth of M.oryzae, suggesting the presence of active enzymes and secondary metabolites. OsiSh-2 is tested positive for PKS-I and NRPS genes and can produce cellulase, protease, gelatinase, siderophore, IAA and ACC deaminase. Preliminary separation indicated that the methanol extract of OsiSh-2 could suppress growth of pathogen; its major active component was identified as nigericin.

CONCLUSION:

Endophytic Streptomyces endus OsiSh-2 has potential as a biocontrol agent against rice blast in agriculture.

See http://www.ncbi.nlm.nih.gov/pubmed/27293085