DOI：10.1038/nature17413 作者：Hidenori Takeuchi
摘要 : 在开花植物中，雌配子体分泌作为化学引诱剂的肽来引导花粉管生长，使其能够将不动的精子输送给被胚珠封闭在内的雌配子体。本期Na
在开花植物中，雌配子体分泌作为化学引诱剂的肽来引导花粉管生长，使其能够将不动的精子输送给被胚珠封闭在内的雌配子体。本期Nature上发表的两篇论文报告了这些雌性引诱剂之一的LURE1的雄性花粉管细胞表面受体在模型植物拟南芥中的发现。Wei-Cai Yang及同事发现，LURE1会被一种受体样激酶复合物 (异聚体 “MDIS1–MIK”)感应到。)(Nature:中科院遗传发育所杨维才研究组揭示发现植物雌雄识别的分子机制)Tetsuya Higashiyama 和 Hidenori Takeuchi 报告说， “花粉特异性受体样激酶-6” (PRK6)是感应LURE1所需的，PRK6与PRK家族的其他受体一起发挥作用。这两个研究小组都通过改变拟南芥姐妹种Capsella rubella的花粉管、使其表达拟南芥受体的一个成分(MDIS1 或 PRK6)，显示了这两个种之间的生殖隔离已经部分瓦解了。
Directional control of tip-growing cells is essential for proper tissue organization and cell-to-cell communication in animals and plants1, 2. In the sexual reproduction of flowering plants, the tip growth of the male gametophyte, the pollen tube, is precisely guided by female cues to achieve fertilization3. Several female-secreted peptides have recently been identified as species-specific attractants that directly control the direction of pollen tube growth4, 5, 6. However, the method by which pollen tubes precisely and promptly respond to the guidance signal from their own species is unknown. Here we show that tip-localized pollen-specific receptor-like kinase 6 (PRK6) with an extracellular leucine-rich repeat domain is an essential receptor for sensing of the LURE1 attractant peptide in Arabidopsis thaliana under semi-in-vivo conditions, and is important for ovule targeting in the pistil. PRK6 interacted with pollen-expressed ROPGEFs (Rho of plant guanine nucleotide-exchange factors), which are important for pollen tube growth through activation of the signalling switch Rho GTPase ROP1 (refs 7, 8). PRK6 conferred responsiveness to AtLURE1 in pollen tubes of the related species Capsella rubella. Furthermore, our genetic and physiological data suggest that PRK6 signalling through ROPGEFs and sensing of AtLURE1 are achieved in cooperation with the other PRK family receptors, PRK1, PRK3 and PRK8. Notably, the tip-focused PRK6 accumulated asymmetrically towards an external AtLURE1 source before reorientation of pollen tube tip growth. These results demonstrate that PRK6 acts as a key membrane receptor for external AtLURE1 attractants, and recruits the core tip-growth machinery, including ROP signalling proteins. This work provides insights into the orchestration of efficient pollen tube growth and species-specific pollen tube attraction by multiple receptors during male–female communication.
来源： Nature 浏览次数：0