Transcriptome analysis of rice leaves in response to Rhizoctonia solani infection

Abstract

Background: Sheath blight disease (ShB) is one of the important diseases that severely affects rice production. However, the mechanism of defense against ShB remains unclear. To understand the molecular mechanism of rice defense to ShB, an RNA-sequencing analysis was performed using Rhizoctonia solani AG1-IA-inoculated rice leaves. Results: After 48 hours of inoculation, 6,838 genes were differentially expressed in rice leaves (>2 fold, P<0.05). Among them, 3,802 genes were upregulated, while 3,036 were downregulated compared to the control group. In addition, the differentially expressed genes were classified via GO, KEGG, and Mapman analyses. Thirty GO terms, including biological process, molecular function, and cellular component, were significantly enriched, and 30 KEGG pathways included ribosome, carbon metabolism, and biosynthesis of amino acids. A Mapman analysis demonstrated that the phytohormone and metabolic pathways were significantly altered. Interestingly, the expression levels of 359 transcription factors, including WRKY, MYB, and NAC family members, as well as 239 transporter genes, including ABC, MFS, and SWEET, were significantly changed upon R. solani AG1-IA inoculation. An additional genetic study showed that OsWRKY53 negatively and OsAKT1 positively regulate rice defense to R. solani, respectively. In addition, interestingly, many differentially expressed genes contain R. solani-responsive cis-elements in their promoter region. Conclusions: Taken together, our analyses provide valuable information for the additional study of rice defense mechanisms to ShB, and the genes identified could be useful in the future to breed resistant rice.