Sclerenchyma cell thickening through enhanced lignification induced by OsMYB30 prevents fungal penetration of rice leaves.

作者：Wei-Tao Li, Kang Wang, Mawsheng Chern, Yuchen Liu, Ziwei Zhu, Jiang Liu, Xiaobo Zhu, Jun-Jie Yin, Li Ran, J. Xiong, Kaiwei He, Li-Ting Xu, Min He, Jing Wang, Jia-Li Liu, Yu Bi, Hai Qing, Mingwu Li, Kun Hu, Lin-Hua Song, Long Wang, Tuo Qi, Qing-Qing Hou, Wei-Lan Chen, Yan Li, Wen-Ming Wang, Xuewei Chen · 发表于：New Phytologist · 年份：2020 · DOI：10.1111/nph.16505 · 被引用次数：133 · 研究领域：Medicine、Chemistry

Broad-spectrum resistance is highly preferred in crop breeding programs. Previously, we reported the identification of the broad-spectrum resistance-Digu 1 (bsr-d1) allele from rice Digu. The bsr-d1 allele prevents activation of Bsr-d1 expression by Magnaporthe oryzae infection and degradation of H2 O2 by peroxidases, leading to resistance to M. oryzae. However, it remains unknown whether defense pathways other than H2 O2 burst and peroxidases contribute to the bsr-d1-mediated immunity. Blast resistance was determined in rice leaves by spray and punch inoculations. Target genes of OsMYB30 was identified by one-hybrid assays in yeast and electrophoretic mobility shift assay. Lignin contents were measured by phloroglucinol-HCl staining, and acetyl bromide and thioacidolysis methods. Here, we report the involvement of the OsMYB30 gene in the bsr-d1-mediated blast resistance. Expression of OsMYB30 is induced during M. oryzae infection or when Bsr-d1 is knocked out or downregulated, as occurs in bsr-d1 plants upon infection. We further find that OsMYB30 binds to and activates the promoters of 4-coumarate:coenzyme A ligase genes (Os4CL3 and Os4CL5) resulting in accumulation of lignin subunits G and S. This action leads to obvious thickening of sclerenchyma cells near the epidermis, inhibiting M. oryzae penetration at the early stage of infection. Our study reveals novel components required for bsr-d1-mediated resistance and penetration-dependent immunity, and advances our understan...