Experimental validation of emamectin as predicted from the meta-analysis of in planta RNA-Seq data as a potential antifungal agent against Magnaporthe oryzae.

Abstract

Magnaporthe oryzae is a fungus that infects monocotyledons such as rice, causing rice blast with reduced grain quality and hence is a significant challenge to food security. Although several fungicides are used, they are less effective and toxic with prolonged application. In this work on M. oryzae, we identified the protein targets that could be used for anti-fungal drug design based on meta-analysis of RNA-seq data retrieved from five experiments conducted on in planta M. oryzae isolated from infected rice at different time points ( < = 144 hpi). Through RNA-seq analysis, highly expressed genes (HEGs) were identified that were common across different experiments. WGCNA analysis further revealed clusters of co-expressed genes from which hub genes were identified which were also highly expressed. From the results of this study, genes such as MGG_05447, MGG_04732, and MGG_03619 were identified as potential targets for designing more effective fungicides. We selected MGG_04732 (chitinase) as a drug target and using virtual screening, molecular docking and molecular dynamics simulations, we identified emamectin as a potential antifungal agent that could act against it. The antifungal effectiveness of emamectin was further confirmed experimentally which showed it to have the ability to inhibit the growth of M. oryzae as demonstrated by the reduction in radial growth and melanin content. The results of this paper could be utilized for further field studies and applied in the design of new antifungals.