Transcriptome sequencing and gene expression analysis reveals differential expression in response to YVMV infection in contrasting genotypes of okra

Yellow vein mosaic virus (YVMV) is a major viral diseases, which causes substantial yield losses upto 80 - 90 % in okra crop. In the present investigation, a comparative transcriptome analysis was performed using contrast genotypes of okra to understand the molecular basis of the defense mechanism against YVMV. It was observed that out of 6,040 differentially expressed genes (DEGs), 1,174 and 1,846 genes were up regulated and down regulated respectively in comparison to susceptible infected (SI) and resistant infected (RI) plants. A substantial number of DEGs were related to plant defense responses, such as calmodulin-binding protein, glutathione metabolic process, genes in the gene silencing pathway, MLO-like protein, pathogen-related protein, MLP-like protein, etc. A few selected genes, including Nudix hydrolase, SAG 21, Peroxidase, RING-H2 finger protein, GRXC 6, NBS-LRR and bHLH-TFs, NAC-TFs and MAPKKK.18 were validated using quantitative real-time PCR (qPCR) during the disease progression in contrasting parents. The study showed both positive and negative regulators of virus resistance were involved, also observed the gene expression patterns of these regulators varied significantly in susceptible and resistant plants as the disease progressed. These findings could help to understand the YVMV tolerance mechanism and further aid in the development of breeding and genetic engineering strategies to overcome YVMV infection.