Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China.
Key Laboratory of Digital Upland Crops of Zhejiang Province, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310014, China.
Plant Physiol. 2024 Oct 1;196(2):1095-1109. doi: 10.1093/plphys/kiae371.
The methylation of N6-methyladenosine (m6A) involves writers, erasers, and readers, acting synergistically in posttranscriptional regulation. These processes influence various biological processes, including plant floral transition. However, the specific role of m6A modifications in photoperiod sensitivity in cotton (Gossypium hirsutum) remains obscure. To elucidate this, in this study, we conducted transcriptome-wide m6A sequencing during critical flowering transition stages in the photoperiod-sensitive wild G. hirsutum var. yucatanense (yucatanense) and the photoperiod-insensitive cultivated cotton G. hirsutum acc. TM-1 (TM-1). Our results revealed significant variations in m6A methylation of 2 cotton varieties, with yucatanense exhibiting elevated m6A modification levels compared with TM-1 under long-day conditions. Notably, distinct m6A peaks between TM-1 and yucatanense correlated significantly with photoperiod sensitivity. Moreover, our study highlighted the role of the demethylase G. hirsutum ALKB homolog 5 (GhALKBH5) in modulating m6A modification levels. Silencing GhALKBH5 led to a decreased mRNA level of key photoperiodic flowering genes (GhADO3, GhAGL24, and GhFT1), resulting in delayed bud emergence and flowering. Reverse transcription quantitative PCR analyses confirmed that silencing GhADO3 and GhAGL24 significantly downregulated the expression of the floral integrator GhFT1. Collectively, our findings unveiled a transcriptional regulatory mechanism in which GhALKBH5-mediated m6A demethylation of crucial photoperiodic flowering transcripts modulated photoperiod sensitivity in cotton.
N6-甲基腺苷（m6A）的甲基化涉及writers、erasers 和 readers，它们在转录后调控中协同作用。这些过程影响各种生物过程，包括植物花发育的转变。然而，m6A 修饰在棉花（Gossypium hirsutum）光周期敏感性中的具体作用仍不清楚。为了阐明这一点，在这项研究中，我们在光周期敏感的野生棉花 G. hirsutum var. yucatanense（yucatanense）和光周期不敏感的栽培棉花 G. hirsutum acc. TM-1（TM-1）的关键开花转变阶段进行了全转录组 m6A 测序。我们的结果显示，两种棉花品种的 m6A 甲基化存在显著差异，yucatanense 在长日照条件下表现出比 TM-1 更高的 m6A 修饰水平。值得注意的是，TM-1 和 yucatanense 之间明显的 m6A 峰与光周期敏感性显著相关。此外，我们的研究强调了去甲基化酶 G. hirsutum ALKB 同源物 5（GhALKBH5）在调节 m6A 修饰水平方面的作用。沉默 GhALKBH5 导致关键光周期开花基因（GhADO3、GhAGL24 和 GhFT1）的 mRNA 水平降低，导致芽萌发和开花延迟。逆转录定量 PCR 分析证实，沉默 GhADO3 和 GhAGL24 显著下调了花整合因子 GhFT1 的表达。总之，我们的研究结果揭示了一种转录调控机制，即 GhALKBH5 介导的关键光周期开花转录物的 m6A 去甲基化调节棉花的光周期敏感性。
