F-actin regulates the polarized secretion of pollen tube attractants in Arabidopsis synergid cells
F-actin regulates the polarized secretion of pollen tube attractants in Arabidopsis synergid cells
复制标题
F-肌动蛋白调节拟南芥助细胞花粉管引诱剂的极化分泌
DOI：
10.1093/plcell/koac371
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Maruyama, Daisuke
中科院分区：
文献类型：
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作者：
Susaki, Daichi;Izumi, Rie;Oi, Takao;Takeuchi, Hidenori;Shin, Ji Min;Sugi, Naoya;Kinoshita, Tetsu;Higashiyama, Tetsuya;Kawashima, Tomokazu;Maruyama, Daisuke
花粉管吸引是开花植物有性繁殖的关键事件。在胚珠中，与卵细胞相邻的两个助细胞通过从面向珠孔的丝状器（FA）主动分泌引诱肽（例如 AtLURE1 和 XIUQIU）来控制花粉管的到达。独特的细胞极性以及纵向F-肌动蛋白和微管是不同物种中助细胞的标志，尽管这些细胞结构的功能尚不清楚。在本研究中，我们使用遗传和药理学方法来阐明细胞骨架成分在拟南芥 FA 形成和花粉管引导中的作用。微管形成的遗传抑制减少了质膜的内陷，但并没有消除珠孔 AtLURE1.2 的积累。相比之下，显性失活形式的 ACTIN8 表达会导致 FA 解体，并导致 AtLURE1.2 向 FA 分布的极性丧失。有趣的是，花粉管接收后，持续助细胞中的 F-肌动蛋白在几个小时内变得不清楚，这可能参与早期多管阻塞期间花粉管吸引的暂停和恢复。我们的数据表明，F-肌动蛋白在维持细胞极性和介导助细胞中的男女通讯方面发挥着核心作用。
Pollen tube attraction is a key event of sexual reproduction in flowering plants. In the ovule, two synergid cells neighboring the egg cell control pollen tube arrival via the active secretion of attractant peptides such as AtLURE1 and XIUQIU from the filiform apparatus (FA) facing toward the micropyle. Distinctive cell polarity together with longitudinal F-actin and microtubules are hallmarks of the synergid cell in various species, though the functions of these cellular structures are unclear. In this study, we used genetic and pharmacological approaches to indicate the roles of cytoskeletal components in FA formation and pollen tube guidance inArabidopsis thaliana. Genetic inhibition of microtubule formation reduced invaginations of the plasma membrane but did not abolish micropylar AtLURE1.2 accumulation. By contrast, the expression of a dominant-negative form of ACTIN8 induced disorganization of the FA and loss of polar AtLURE1.2 distribution toward the FA. Interestingly, after pollen tube reception, F-actin became unclear for a few hours in the persistent synergid cell, which may be involved in pausing and resuming pollen tube attraction during early polytubey block. Our data suggest that F-actin plays a central role in maintaining cell polarity and in mediating male–female communication in the synergid cell.