Actin-depolymerizing factors 8 and 11 promote root hair elongation at high pH
Actin-depolymerizing factors 8 and 11 promote root hair elongation at high pH
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DOI：
10.1016/j.xplc.2023.100787
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发表时间：
2024-03-11
影响因子：
10.5
通讯作者：
Xiang，Yun
中科院分区：
文献类型：
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作者：
Qian，Dong;Li，Tian;Xiang，Yun
根毛是一种极细长的单细胞结构，源自根表皮细胞，具有从周围环境吸收水和营养物质的功能。之前的报告表明，短时间的高 pH 值会抑制根毛的延伸；但长期高pH值处理对根毛生长的影响仍不清楚。在这里，我们报告说，随着外部 pH 值的增加，根毛伸长的持续时间显着延长，这抵消了根毛伸长率降低的影响，最终产生更长的根毛，而肌动蛋白解聚因子 8 和 11 (ADF8/11) 功能的丧失导致在高 pH 值 (pH 7.4) 下根毛长度缩短。高 pH 值会抑制 ADF8/11 在根毛尖端的积累，并且环境 pH 值的升高会影响根毛尖端的肌动蛋白丝 (F-actin) 网络。在高 pH 条件下，theadf8/11 突变体的根毛中不存在以尖端为中心的 F-肌动蛋白网络，theadf8/11 根毛尖端的肌动蛋白丝紊乱，并且肌动蛋白周转减弱。在高 pH 条件下，分泌囊泡和回收囊泡不会聚集在 adf8/11 根毛的顶端区域。总之，我们的结果表明，在长期暴露于高细胞外 pH 的情况下，ADF8/11 可能建立并维持以尖端为中心的 F-肌动蛋白网络，以调节根毛尖端分泌/回收囊泡的极性运输，从而促进根毛伸长。
A root hair is a polarly elongated single-celled structure that derives from a root epidermal cell and functions in uptake of water and nutrients from the surrounding environment. Previous reports have demonstrated that short periods of high pH inhibit root hair extension; but the effects of long-term high-pH treatment on root hair growth are still unclear. Here, we report that the duration of root hair elongation is significantly prolonged with increasing external pH, which counteracts the effect of decreasing root hair elongation rate and ultimately produces longer root hairs, whereas loss of actin-depolymerizing factor 8 and 11 (ADF8/11) function causes shortening of root hair length at high pH (pH 7.4). Accumulation of ADF8/11 at the tips of root hairs is inhibited by high pH, and increasing environmental pH affects the actin filament (F-actin) meshwork at the root hair tip. At high pH, the tip-focused F-actin meshwork is absent in root hairs of theadf8/11 mutant, actin filaments are disordered at theadf8/11root hair tips, and actin turnover is attenuated. Secretory and recycling vesicles do not aggregate in the apical region ofadf8/11root hairs at high pH. Together, our results suggest that, under long-term exposure to high extracellular pH, ADF8/11 may establish and maintain the tip-focused F-actin meshwork to regulate polar trafficking of secretory/recycling vesicles at the root hair tips, thereby promoting root hair elongation.