Utilization of fungal biocontrol agents against rice sheath blight disease provides insight into their role in plant defense responses

Abstract

Biotic and abiotic factors have an effect on rice production all around the world. Diseases are regarded as major restrictions among the biotic stressors, and rice sheath blight (Rhizoctonia solani Kühn) is one of the most calamitous diseases that significantly damage the crop. Lately, biocontrol of fungal plant pathogens has appeared as an appealing approach. The present investigation was undertaken to evaluate different biocontrol agents like Talaromyces flavus, Chaetomium globosum, Pseudomonas fluorescens and Aspergillus niger against sheath blight disease. Prior to sowing, seeds were bioprimed with each isolate and sown in the nursery. After 21 days, seedlings were transplanted in-vivo and were inoculated with a virulent isolate of Rhizoctonia solani at maximum tillering stage. Observations on biochemical parameters and gene expression studies were carried out at 24, 48, 72, and 96 hpi. Enzymatic activity viz., chitinase, β-1,3-glucanase, catalase, and PAL was observed  maximum in Chaetomium globosum. PR-genes viz., IPT, BrD, HmPr, AMP, AldD, NIC and LisH showed up-regulation at 96 hpi. Chaetomium globosum had the highest yield, maximum number of tillers with least RLH% as compared to other treatments. However, results indicated biocontrol agents are helpful and they induce multitude of defence responses against R. solani in rice.