An MAPK Pathway in Papilla Cells for Successful Pollination in Arabidopsis
An MAPK Pathway in Papilla Cells for Successful Pollination in Arabidopsis
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拟南芥成功授粉的乳头细胞中的 MAPK 途径
DOI：
10.1016/j.molp.2020.10.003
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发表时间：
2020
期刊：
影响因子：
27.5
通讯作者：
Fujii Sota
中科院分区：
文献类型：
--
作者：
Kato Yoshinobu;Fujii Sota
在菊科植物的授粉过程中，花粉与雌蕊顶端的乳突细胞相互沟通，引发花粉水化、萌发和自交不亲和等生理反应。据认为，乳突细胞急剧地改变它们的细胞环境以进行水和钙离子释放，并为花粉萌发和花粉管伸长提供能量来源（Doucet et al.，2016年）。例如，在亲和授粉期间发生肌动蛋白重组和含有钙离子的囊泡向质膜的运输，并且在自交不亲和授粉期间改变细胞质中的钙离子动力学（Iwano et al. 2015年; Doucet等人，2016年）。乳突细胞中的胞吐作用也是有效亲和授粉的必要过程（Samuel等人，2009年）。解开调控这些反应的信号通路是理解授粉过程的基本机制和改进作物育种策略的重要任务。在菊科中，自交不亲和反应的起始信号被充分研究（Takayama和Isogai，2005）。S位点蛋白11/S富含半胱氨酸的肽配体（SP11/SCR）和S受体激酶（SRK）分别是乳突细胞中花粉被和质膜上的决定因子。这两种蛋白质都在S基因座编码，并且存在一系列单倍型（S-单倍型），即自我/非自我辨别的遗传条形码。SP11与SRK结合，如果它们来自相同的S-单倍型（自花授粉）。SRK当被SP11结合磷酸化下游因子激活时，自花粉水合、萌发和/或穿透过程被抑制。相对于这种已被广泛研究的自排斥机制，亲和授粉的信号途径，雌蕊接受花粉的机制，仍然研究得很少。
During the pollination process in Brassicaceae, pollen and papilla cells at the tip of the pistil communicate with each other and trigger various physiological responses such as pollen hydration/germination and self-incompatibility. It was thought that papilla cells drastically change their cellular environment to conduct water and calcium-ion release and to provide an energy source for pollen germination and pollen-tube elongation (Doucet et al., 2016). For example, actin reorganization and transport of vesicles containing calcium ions to plasma membranes occur during compatible pollination, and calcium-ion dynamics in the cytoplasm are changed during self-incompatible pollination (Iwano et al., 2015; Doucet et al., 2016). Exocytosis in papilla cells is also an essential process for effective compatible pollination (Samuel et al., 2009). Unraveling signaling pathways regulating these responses is an important task in understanding the basic mechanism of the pollination process and improving crop-breeding strategies.The initiation signal for the self-incompatibility response in Brassicaceae is well studied (Takayama and Isogai, 2005). S-locus protein 11/S cysteine-rich peptide ligand (SP11/SCR) and S-receptor kinase (SRK) are the determinants at the pollen coat and plasma membrane in papilla cells, respectively. Both of these proteins are encoded in the S-locus, and there is a series of haplotypes (S-haplotype), the genetic barcodes of self-/non-self-discrimination. SP11 binds to SRK if they originate from the same S-haplotype (self-pollination). SRK when activated by SP11-binding phosphorylates downstream factors, and self-pollen hydration, germination, and/or penetration processes are inhibited. Compared with this well-studied self-rejection mechanism, signal pathways for compatible pollination, the pistil mechanism to accept pollen, remain much less investigated.