Halotropism Is a Response of Plant Roots to Avoid a Saline Environment
Halotropism Is a Response of Plant Roots to Avoid a Saline Environment
复制标题
DOI：
10.1016/j.cub.2013.08.042
复制
发表时间：
2013-10-21
期刊：
影响因子：
9.2
通讯作者：
Testerink, Christa
中科院分区：
文献类型：
--
作者：
Galvan-Ampudia, Carlos S.;Julkowska, Magdalena M.;Testerink, Christa
向性代表了植物如何通过适应其生长和发育来响应环境信号的有趣例子。在这里，报道了一种新的向性，即向盐性，它允许植物幼苗通过避开盐分环境来减少对盐分的暴露。为了响应盐梯度，拟南芥、番茄和高粱根被发现会主动优先考虑沿着重力轴远离盐度的生长。这种反应的方向性是通过植物激素生长素在根尖的主动重新分布而建立的，这是由 PIN-FORMED 2 (PIN2) 生长素外排载体介导的。我们发现盐诱导的磷脂酶 D 活性会刺激根部面对较高盐浓度一侧的网格蛋白介导的 PIN2 内吞作用。 PIN2 的细胞内重新定位允许生长素重新分布，并使根定向弯曲远离较高的盐浓度。因此，我们的结果确定了环境信号与生长素调节的根生长整合所必需的细胞途径，该途径可能在植物对盐胁迫的适应性反应中发挥关键作用。
Tropisms represent fascinating examples of how plants respond to environmental signals by adapting their growth and development. Here, a novel tropism is reported, halotropism, allowing plant seedlings to reduce their exposure to salinity by circumventing a saline environment. In response to a salt gradient, Arabidopsis, tomato, and sorghum roots were found to actively prioritize growth away from salinity above following the gravity axis. Directionality of this response is established by an active redistribution of the plant hormone auxin in the root tip, which is mediated by the PIN-FORMED 2 (PIN2) auxin efflux carrier. We show that salt-induced phospholipase D activity stimulates clathrin-mediated endocytosis of PIN2 at the side of the root facing the higher salt concentration. The intracellular relocalization of PIN2 allows for auxin redistribution and for the directional bending of the root away from the higher salt concentration. Our results thus identify a cellular pathway essential for the integration of environmental cues with auxin-regulated root growth that likely plays a key role in plant adaptative responses to salt stress.