Basally distributed actin array drives embryonic hypocotyl elongation during the seed-to-seedling transition in Arabidopsis
Basally distributed actin array drives embryonic hypocotyl elongation during the seed-to-seedling transition in Arabidopsis
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DOI：
10.1111/nph.19149
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发表时间：
2023-08-03
期刊：
影响因子：
9.4
通讯作者：
Li，Jiejie
中科院分区：
文献类型：
--
作者：
Cui，Xuan;Zou，Minxia;Li，Jiejie
种子萌发是种子植物有性生殖产生后代的重要发育过程。种子到幼苗的转变主要由下胚轴细胞伸长驱动。然而，下胚轴生长的机制仍然是未知的，在这项研究中，我们的特点是肌动蛋白阵列重组胚胎下胚轴表皮细胞。活细胞成像显示在下胚轴细胞伸长过程中形成的基本组织化的肌动蛋白阵列。这种极化的肌动蛋白组装体是一个桶形的网络，它包括纵向排列的肌动蛋白电缆和连接这些电缆的精细肌动蛋白帽的骨干。我们提供的遗传证据表明，基础肌动蛋白阵列的形成需要肌动蛋白介导的肌动蛋白聚合和由肌球蛋白XIs驱动的肌动蛋白丝的定向运动。与野生型相比，在1 - 1和xi 3 komutants中，肌动蛋白丝不能重组成基础肌动蛋白阵列，下胚轴细胞的伸长受到抑制。总的来说，我们的工作揭示了基础肌动蛋白阵列组装的分子机制，并证明了肌动蛋白极化与种子到幼苗转变过程中下胚轴伸长之间的联系。
Seed germination is a vital developmental transition for the production of progeny by sexual reproduction in spermatophytes. The seed‐to‐seedling transition is predominately driven by hypocotyl cell elongation. However, the mechanism that underlies hypocotyl growth remains largely unknown.In this study, we characterized the actin array reorganization in embryonic hypocotyl epidermal cells. Live‐cell imaging revealed a basally organized actin array formed during hypocotyl cell elongation. This polarized actin assembly is a barrel‐shaped network, which comprises a backbone of longitudinally aligned actin cables and a fine actin cap linking these cables.We provide genetic evidence that the basal actin array formation requires formin‐mediated actin polymerization and directional movement of actin filaments powered by myosin XIs. Infh1‐1andxi3komutants, actin filaments failed to reorganize into the basal actin array, and the hypocotyl cell elongation was inhibited compared with wild‐type plants.Collectively, our work uncovers the molecular mechanisms for basal actin array assembly and demonstrates the connection between actin polarization and hypocotyl elongation during seed‐to‐seedling transition.