Gene Expression Analysis of Resistant and Susceptible Rice Cultivars to Sheath Blight after Inoculation with Rhizoctonia Solani

Abstract

\n Background: Rice sheath blight, caused by Rhizoctonia solani Kühn (teleomorph: Thanatephorus cucumeris), is one of the most severe diseases in rice (Oryza sativa L.) worldwide. Studies on resistance genes and resistance mechanisms of rice sheath blight has mainly focused on indica rice. Rice sheath blight is a growing threat to rice production with the increasing planting area of japonica rice in Northeast China, and it is therefore essential to explore the mechanism of sheath blight resistance in this rice subspecies.Results: In this study, RNA-seq technology was used to analyse the gene expression changes of leaf sheath inoculation with R. solani at 12, 24, 36, 48, and 72 h after inoculation of the resistant cultivar ‘Shennong 9819’ and susceptible cultivar ‘Yueguang’. A total of 2275 differentially expressed genes (DEGs) were identified in our study. Gene Ontology (GO) annotation and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis of these DEGs showed that the metabolic pathways of the two rice cultivars were similar and approximately covered most of the biological processes after inoculation with R. solani. Conclusion: The main differences between the resistant and susceptible cultivars were the activity of DEGs in response to R. solani and the enrichment of metabolic pathways involved in these genes. Upon experiencing external stress, the genes in the leaf sheath of Shennong 9819 showed a fluctuating response, whereas the genes in the leaf sheath of Yueguang had a higher activity. The phenylalanine metabolism and plant hormone signal transduction play important roles in disease resistance. Their response in the leaf sheath of Shennong 9819 was faster than that of Yueguang, and they were highly enriched at 12 h after inoculation.