Ncl1-dependent m5C RNA methylation promotes appressorial autophagy and pathogenicity in the rice blast fungus

Xuan Cai; Hong Hu; Caiyun Liu; Zhiyong Ren; Yunfeng Li; Yanfang Nie; Hao Liu; Lu Zheng; Junbin Huang; Xiaolin Yang; Xiao-Lin Chen

doi:10.1016/j.xplc.2026.101817

Ncl1-dependent m⁵C RNA methylation promotes appressorial autophagy and pathogenicity in the rice blast fungus

Plant Commun. 2026 Mar 11:101817. doi: 10.1016/j.xplc.2026.101817. Online ahead of print.

Authors

Xuan Cai¹, Hong Hu², Caiyun Liu³, Zhiyong Ren², Yunfeng Li⁴, Yanfang Nie⁴, Hao Liu², Lu Zheng², Junbin Huang², Xiaolin Yang⁵, Xiao-Lin Chen⁶

Affiliations

¹ Hubei Key Laboratory for Crop Diseases, Insect Pests, and Weeds Control, Key Laboratory of Integrated Pest Management on Crops in Central China of the Ministry of Agriculture and Rural Affairs, Institute of Plant Protection and Soil Science, Hubei Academy of Agricultural Sciences, Wuhan, China.
² State Key Laboratory of Agricultural Microbiology, Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
³ Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
⁴ Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
⁵ Hubei Key Laboratory for Crop Diseases, Insect Pests, and Weeds Control, Key Laboratory of Integrated Pest Management on Crops in Central China of the Ministry of Agriculture and Rural Affairs, Institute of Plant Protection and Soil Science, Hubei Academy of Agricultural Sciences, Wuhan, China; Hubei Hongshan Laboratory, Wuhan 430070, China. Electronic address: xiaolinyangxly@163.com.
⁶ State Key Laboratory of Agricultural Microbiology, Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: chenxiaolin@mail.hzau.edu.cn.

PMID: 41821317
DOI: 10.1016/j.xplc.2026.101817

Abstract

Epigenetic regulation, particularly RNA methylation, remains largely unexplored in plant-pathogenic fungi. This study investigates the role of 5-methylcytosine (m⁵C) RNA methylation during infection by Magnaporthe oryzae, the rice blast fungus, with an emphasis on its effects on autophagy. We identified Ncl1, an m⁵C RNA methyltransferase, as essential for fungal virulence and appressorium development. Using m⁵C RNA immunoprecipitation sequencing, we mapped the m⁵C landscape of the M. oryzae transcriptome, identifying 9014 hypomethylated peaks across 5678 genes in the Δncl1 mutant. RNA sequencing analysis revealed that 119 m⁵C-modified genes were upregulated and 199 were downregulated, indicating a key role for Ncl1 in regulating gene expression. Mechanistically, Ncl1-mediated m⁵C methylation stabilizes ATG5 and ATG16 mRNAs, which are essential for Atg8 lipidation, autophagosome formation, and full M. oryzae pathogenicity. Notably, Ncl1 protein stability is modulated by the Pmk1 signaling pathway through phosphorylation and Smt3-mediated SUMOylation. These findings reveal a complex interplay between epigenetic regulation and post-translational modifications in fungi. They highlight the central role of m⁵C RNA methylation in autophagy and pathogenicity in M. oryzae, enhance our understanding of fungal biology, and provide potential targets for antifungal strategies.

Keywords: 5-methylcytosine; Magnaporthe oryzae; RNA methylation; appressorium formation; autophagy.