Light-mediated polarization of the PIN3 auxin transporter for the phototropic response in Arabidopsis
Light-mediated polarization of the PIN3 auxin transporter for the phototropic response in Arabidopsis
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DOI：
10.1038/ncb2208
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发表时间：
2011-04-01
影响因子：
21.3
通讯作者：
Friml, Jiri
中科院分区：
文献类型：
--
作者：
Ding, Zhaojun;Galvan-Ampudia, Carlos S.;Friml, Jiri
向光性是植物向光生长的一种适应性反应(1)。它涉及光感知和植物激素生长素的不对称分布（2-12）。在这里，我们确定了趋光性机制的关键部分，揭示了光感知如何启动生长素重新分配，从而导致定向生长。我们发现，光极化了生长素外排载体PIN3在下胚轴内胚层细胞中的细胞定位，导致生长素分布和生长差异的变化。在黑暗中，PINOID （PID）激酶的高表达和活性与PIN3对所有细胞侧的极性靶向相关。光照后，光抑制PINOID转录，PIN3通过GNOM ARF GTPase GEF（鸟嘌呤核苷酸交换因子）依赖的转运特异性地向细胞内侧极化。因此，在阴影和光照下的下胚轴一侧的不同运输使PIN3极性与光照方向一致，并且可能将生长素流重新定向到阴影侧，生长素促进生长，导致下胚轴向光照弯曲。我们的研究结果表明，在不同的环境和内源性线索下，PID磷酸化依赖性的PIN蛋白募集进入不同的运输途径是一种极化生长素通量的机制
Phototropism is an adaptation response, through which plants grow towards the light(1). It involves light perception and asymmetric distribution of the plant hormone auxin(2-12). Here we identify a crucial part of the mechanism for phototropism, revealing how light perception initiates auxin redistribution that leads to directional growth. We show that light polarizes the cellular localization of the auxin efflux carrier PIN3 in hypocotyl endodermis cells, resulting in changes in auxin distribution and differential growth. In the dark, high expression and activity of the PINOID (PID) kinase correlates with a polar targeting of PIN3 to all cell sides. Following illumination, light represses PINOID transcription and PIN3 ispolarized specifically to the inner cell sides by GNOM ARF GTPase GEF (guanine nucleotide exchange factor)-dependent trafficking. Thus, differential trafficking at the shaded and illuminated hypocotyl side aligns PIN3 polarity with the light direction, and presumably redirects auxin flow towards the shaded side, where auxin promotes growth, causing hypocotyls to bend towards the light. Our results imply that PID phosphorylation-dependent recruitment of PIN proteins into distinct trafficking pathways is a mechanism to polarize auxin fluxes in response to different environmental and endogenous cues