Wang Jinyu, Zheng Leiming, Peng Yexiang, Lu Zizheng, Zheng Minghui, Wang Zi, Liu Juan, He Yan, Luo Jinhong
State Key Laboratory of Maize Bio-Breeding, National Maize Improvement Center, China Agricultural University, Beijing, 100094, China.
Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
New Phytol. 2025 Jan;245(1):200-214. doi: 10.1111/nph.20225. Epub 2024 Oct 25.
The epigenetic process of RNA-directed DNA methylation (RdDM) regulates the expression of genes and transposons. However, little is known about the involvement of RdDM in the response of maize (Zea mays) to salt stress. Here, we isolated a salt-sensitive maize mutant and cloned the underlying gene, which encodes KOW DOMAIN-CONTAINING TRANSCRIPTION FACTOR1 (KTF1), an essential component of the RdDM pathway. Evolutionary analysis identified two homologs of KTF1 (ZmKTF1A and ZmKTF1B) with highly similar expression patterns. Whole-genome bisulfite sequencing revealed that mutations in ZmKTF1 substantially decrease genome-wide CHH (H = A, C, or T) methylation levels. Moreover, our findings suggest that ZmKTF1-mediated DNA methylation regulates the expression of multiple key genes involved in oxidoreductase activity upon exposure to salt, concomitant with increased levels of reactive oxygen species. In addition, insertion-deletion mutations (InDels) in the promoter of ZmKTF1 affect its expression, thereby altering Na concentrations in seedlings in a natural maize population. Therefore, ZmKTF1 might represent an untapped epigenetic resource for improving salt tolerance in maize. Overall, our work demonstrates the critical role of ZmKTF1 involved in the RdDM pathway in maize salt tolerance.
RNA 指导的 DNA 甲基化（RdDM）这一表观遗传过程调控着基因和转座子的表达。然而，关于 RdDM 在玉米（Zea mays）对盐胁迫的响应中的作用，人们了解甚少。在此，我们分离出一个对盐敏感的玉米突变体并克隆了相关基因，该基因编码含 KOW 结构域的转录因子 1（KTF1），它是 RdDM 途径的一个关键组成部分。进化分析鉴定出两个表达模式高度相似的 KTF1 同源物（ZmKTF1A 和 ZmKTF1B）。全基因组亚硫酸氢盐测序显示，ZmKTF1 中的突变显著降低了全基因组范围内 CHH（H = A、C 或 T）的甲基化水平。此外，我们的研究结果表明，ZmKTF1 介导 的 DNA 甲基化在盐胁迫下调节多个参与氧化还原酶活性的关键基因的表达，同时伴随着活性氧水平的升高。另外，ZmKTF1 启动子中的插入缺失突变（InDels）影响其表达，从而改变了天然玉米群体中幼苗的钠浓度。因此，ZmKTF1 可能是提高玉米耐盐性的一种尚未开发的表观遗传资源。总体而言，我们的工作证明了 ZmKTF1 在 RdDM 途径中对玉米耐盐性的关键作用。
