The Arabidopsis Diacylglycerol Kinase 4 is involved in nitric oxide-dependent pollen tube guidance and fertilization
The Arabidopsis Diacylglycerol Kinase 4 is involved in nitric oxide-dependent pollen tube guidance and fertilization
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DOI：
10.1101/665810
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
Aloysius Wong;L. Donaldson;M. Portes;J. Eppinger;J. Feijó;C. Gehring
中科院分区：
文献类型：
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作者：
Aloysius Wong;L. Donaldson;M. Portes;J. Eppinger;J. Feijó;C. Gehring
一氧化氮(NO)是一种关键的信号分子，调节着动植物体内的各种生物过程。在动物中，NO调节血管壁张力、神经传递和免疫反应，而在植物中，NO对于发育和对生物和非生物胁迫的反应是必不可少的[1-3]。有趣的是，NO参与动物和植物的有性繁殖，调节与雄配子相关的生理事件[2，4]。在动物中，NO刺激精子运动[4]并与卵母细胞质膜结合[5]，而在植物中，NO介导花粉-柱头相互作用和花粉管引导[6，7]。已经证实在花粉管(PTS)中产生NO[8]，细胞内对NO的反应包括胞浆钙升高、肌动蛋白组织、囊泡运输和细胞壁沉积[7，9]。然而，介导这些反应的NO反应蛋白仍然难以捉摸。在这里，我们表明，缺乏花粉特异的二酰甘油激酶4(DGK4)的拟南芥PTS生长较慢，对NO依赖的生长抑制和重定向反应不敏感。重组DGK4蛋白在体外产生NO反应的光谱和催化变化，这与PTS中NO感知和信号转导的作用相一致。NO是一种快速、可扩散的气体，根据我们的结果，我们推测在被子植物生殖的孕育期，它可能发挥着DGK4下游信号介导的远程信号和/或快速细胞间通讯功能。
Nitric oxide (NO) is a key signaling molecule that regulates diverse biological processes in both animals and plants. In animals, NO regulates vascular wall tone, neurotransmission and immune response while in plants, NO is essential for development and responses to biotic and abiotic stresses [1–3]. Interestingly, NO is involved in the sexual reproduction of both animals and plants mediating physiological events related to the male gamete [2, 4]. In animals, NO stimulates sperm motility [4] and binding to the plasma membrane of oocytes [5] while in plants, NO mediates pollen-stigma interactions and pollen tube guidance [6, 7]. NO generation in pollen tubes (PTs) has been demonstrated [8] and intracellular responses to NO include cytosolic Ca2+ elevation, actin organization, vesicle trafficking and cell wall deposition [7, 9]. However, the NO-responsive proteins that mediate these responses are still elusive. Here we show that PTs of Arabidopsis lacking the pollen-specific Diacylglycerol Kinase 4 (DGK4) grow slower and become insensitive to NO-dependent growth inhibition and re-orientation responses. Recombinant DGK4 protein yields NO-responsive spectral and catalytic changes in vitro which are compatible with a role in NO perception and signaling in PTs. NO is a fast, diffusible gas and, based on our results, we hypothesize it could serve in long range signaling and/or rapid cell-cell communication functions mediated by DGK4 downstream signaling during the progamic phase of angiosperm reproduction.