State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan 430072, China.
Plant Cell. 2022 Jul 30;34(8):2989-3005. doi: 10.1093/plcell/koac136.
During angiosperm male gametogenesis, microspores divide to produce a vegetative cell (VC) and a male germline (MG), each with distinct cell fates. The mechanism underlying determination of the MG cell/VC fate remains an important area of research, with many unanswered questions. Here, we report that H3K27me3 is essential for VC fate commitment in male Arabidopsis thaliana gametophytes; H3K27me3 erasure contributes to MG cell fate initiation. VC-targeted H3K27me3 erasure disturbed VC development and shifted the VC fate toward a gamete destination, which suggests that MG cells require H3K27me3 erasure to trigger gamete cell fate. Multi-omics and cytological analyses confirmed the occurrence of extensive cell identity transition due to H3K27me3 erasure. Therefore, we experimentally confirmed that MG cell/VC fate is epigenetically regulated. H3K27 methylation plays a critical role in guiding MG cell/VC fate determination for pollen fertility in Arabidopsis. Our work also provides evidence for two previous hypotheses: the germline cell fate is specified by the differential distribution of unknown determinants and VC maintains the default microspore program (i.e. the H3K27me3 setting) while MG requires reprogramming.
在被子植物雄性配子体发生过程中，小孢子分裂产生营养细胞（VC）和雄性生殖细胞（MG），每个细胞都具有不同的命运。MG 细胞/VC 命运决定的机制仍然是一个重要的研究领域，有许多问题尚未得到解答。在这里，我们报告 H3K27me3 对于拟南芥雄性配子体中 VC 命运决定是必不可少的；H3K27me3 的擦除有助于 MG 细胞命运的起始。针对 VC 的 H3K27me3 擦除扰乱了 VC 的发育，并将 VC 命运向配子目的地转移，这表明 MG 细胞需要 H3K27me3 的擦除来触发配子细胞命运。多组学和细胞学分析证实了由于 H3K27me3 的擦除而发生的广泛细胞身份转变。因此，我们通过实验证实了 MG 细胞/VC 命运是受表观遗传调控的。H3K27 甲基化在指导拟南芥花粉育性的 MG 细胞/VC 命运决定中起着关键作用。我们的工作还为两个先前的假说提供了证据：生殖细胞命运是由未知决定因素的差异分布指定的，而 VC 保持默认的小孢子程序（即 H3K27me3 设定），而 MG 需要重新编程。
