Transcriptome analysis of a rice cultivar reveals the differentially expressed genes in response to wild and mutant strains of Xanthomonas oryzae pv. oryzae

Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is a devastating disease in most of the rice growing regions worldwide. Among the 42 BB resistance (R) genes, Xa23 is an executor R gene, conferring broad-spectrum disease resistance to all naturally occurring biotypes of Xoo. In this study, CBB23, a rice line carrying Xa23 gene, was inoculated with wild PXO99(A) and its mutant, P99M2, to retrieve the differentially expressed genes (DEGs). RNA-Seq analysis retrieved 1,235 DEGs (p-value <= 0.05) at 12, 24, 36, and 48 hours of post inoculation (hpi). Gene ontology (GO) analysis classified the DEGs functionally into biological process, cellular component and molecular function. KEGG pathway analysis categorized the DEGs into 11 different pathways, and the ribosome is a prominent pathway followed by biosynthesis of phenylpropanoids. Gene co-expression network analysis identified the clusters of transcription factors (TFs) which may be involved in PXO99(A) resistance. Additionally, we retrieved 67 differentially expressed TFs and 26 peroxidase responsive genes which may be involved in disease resistance mechanism. DEGs involved in the host-pathogen interaction, e.g., signaling mechanism, cell wall and plant hormones were identified. This data would be a valuable resource for researchers to identify the candidate genes associated with Xoo resistance.