Molecular mechanisms of disease resistance against sheath blight in grass plants

September 8, 2020

Molecular basis for the development of sheath blight-resistant plants

A joint research team from RIKEN CSRS and Okayama University has demonstrated how grass plants protect themselves from sheath blight, a major disease in cereal crops.

Sheath blight, caused by the soil-born fungus Rhizoctonia solani, is a severe disease in cereal crops, such as rice and maize. To understand molecular mechanisms underlying plant disease resistance against R. solani, the team used natural accessions of a model grass Brachypodium distachyon and investigated their transcriptional response to the pathogen by time-series comparative transcriptome analysis. The analysis revealed that B. distachyon accessions resistant to R. solani rapidly activated defense response, whereas a susceptible accession delayed. A machine learningbased gene regulatory network analysis using the transcriptome dataset identified the BdWRKY38 transcription factor as a specific network hub in the resistant accessions. R. solani resistance in the resistant accessions was compromised by RNAi-based gene silencing of BdWRKY38, and overexpression of BdWRKY38 improved R. solani resistance in the susceptible accession. These results highlight that BdWRKY38 is a central positive regulator of sheath blight resistance in B. distachyon.

The present study provides a molecular basis to develop novel crop protection methods against sheath blight disease.

Original article
The Plant Journal doi:10.1111/tpj.14976
Y. Kouzai, M. Shimizu, K. Inoue, Y. Uehara-Yamaguchi, K. Takahagi, R. Nakayama, T. Matsuura, I. C. Mori, T. Hirayama, S. S.H. Abdelsalam, Y. Noutoshi, K. Mochida,
"BdWRKY38 is required for the incompatible interaction of Brachypodium distachyon with the necrotrophic fungus Rhizoctonia solani".
Yusuke Kouzai; Research Scientist
Keiichi Mochida; Team Leader
Bioproductivity Informatics Research Team