茉莉酸作为一种与抗逆性密切相关的植物激素，主要调控植物对昆虫侵害、病原菌侵染和机械伤害的抗性反应，同时也参与调控根系生长、配子发育及成熟衰老等发育过程。生长素主要在植物的生长发育过程中起调控作用。以前的研究证明，茉莉酸通过调控生长素的生物合成和极性运输来调节拟南芥侧根的形成。生长素的极性输出由极性定位于质膜上的PIN (PIN formed)蛋白介导完成，在植物生长发育过程中起重要调控作用。目前，关于生长素极性运输的研究是植物生物学的热点研究领域之一。
中国科学院遗传与发育生物学研究所基因组生物学研究中心李传友课题组的研究证明，茉莉酸调节PIN2蛋白的内吞和在细胞质膜上的积累。研究发现，低浓度茉莉酸可以抑制PIN2蛋白的内吞，而且这种作用是依赖ASA1介导的生长素生物合成和TIR1/AFBs介导的生长素信号转导。而高浓度茉莉酸可以降低野生型拟南芥中PIN2蛋白在细胞质膜上的积累，特别是在asa1-1突变体中，高浓度茉莉酸处理严重地降低PIN2蛋白在细胞质膜上的积累。遗传学研究表明，高浓度茉莉酸对PIN蛋白的这种作用独立于生长素信号途径。此项研究还发现，茉莉酸通过影响生长素在根尖的侧向分布进而调控植物根的向重性反应。以上结果表明，茉莉酸通过与生长素互作调节植物对外界信号或环境的适应性反应。
该项研究为进一步揭示茉莉酸调控生长素转运蛋白胞内运输和降解的分子机制提供了新的思路。这项成果4月9日在线发表于国际杂志New Phytologist。李传友实验室孙加强副研究员和在读博士陈谦为该论文共同第一作者。
该研究得到了科技部和国家自然科学基金委的资助。（生物谷Bioon.com）
生物谷推荐原文出处：
New Phytologist DOI: 10.1111/j.1469-8137.2011.03713.x
Jasmonate modulates endocytosis and plasma membrane accumulation of the Arabidopsis PIN2 protein
Jiaqiang Sun1,2,?, Qian Chen1,?, Linlin Qi1, Hongling Jiang1, Shuyu Li1, Yingxiu Xu1, Fang Liu1, Wenkun Zhou1, Jianwei Pan3, Xugang Li2,4, Klaus Palme2,4, Chuanyou Li1,
Keywords:Arabidopsis thaliana;auxin;endocytosis;jasmonate;PIN2
Summary
The subcellular distribution of the PIN-FORMED (PIN) family of auxin transporters plays a critical role in auxin gradient-mediated developmental processes, including lateral root formation and gravitropic growth.?Here, we report two distinct aspects of CORONATINE INSENSITIVE 1 (COI1)- and AUXIN RESISTANT 1 (AXR1)-dependent methyl jasmonate (MeJA) effects on PIN2 subcellular distribution: at lower concentration (5 μM), MeJA inhibits PIN2 endocytosis, whereas, at higher concentration (50 μM), MeJA reduces PIN2 accumulation in the plasma membrane.?We show that mutations of ASA1 (ANTHRANILATE SYNTHASE a1) and the TIR1/AFBs (TRANSPORT INHIBITOR RESPONSE 1/AUXIN-SIGNALING F-BOX PROTEINs) auxin receptor genes impair the inhibitory effect of 5 μM MeJA on PIN2 endocytosis, suggesting that a lower concentration of jasmonate inhibits PIN2 endocytosis through interaction with the auxin pathway. In contrast, mutations of ASA1 and the TIR1/AFBs auxin receptor genes enhance, rather than impair, the reduction effect of 50 μM MeJA on the plasma membrane accumulation of PIN2, suggesting that this action of jasmonate is independent of the auxin pathway. In addition to the MeJA effects on PIN2 endocytosis and plasma membrane residence, we also show that MeJA alters lateral auxin redistribution on gravi-stimulation, and therefore impairs the root gravitropic response.?Our results highlight the importance of jasmonate–auxin interaction in the coordination of plant growth and the adaptation response
