Zhang Fangyuan, Fu Xueqing, Lv Zongyou, Shen Qian, Yan Tingxian, Jiang Weiming, Wang Guofeng, Sun Xiaofen, Tang Kexuan
Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Biomed Res Int. 2014;2014:521794. doi: 10.1155/2014/521794. Epub 2014 Oct 28.
The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. Additionally, ABA also regulates secondary metabolism such as artemisinin in the medicinal plant Artemisia annua L. Although an earlier study showed that ABA receptor, AaPYL9, plays a positive role in ABA-induced artemisinin content improvement, many components in the ABA signaling pathway remain to be elucidated in Artemisia annua L. To get insight of the function of AaPYL9, we isolated and characterized an AaPYL9-interacting partner, AaPP2C1. The coding sequence of AaPP2C1 encodes a deduced protein of 464 amino acids, with all the features of plant type clade A PP2C. Transcriptional analysis showed that the expression level of AaPP2C1 is increased after ABA, salt, and drought treatments. Yeast two-hybrid and bimolecular fluorescence complementation assays (BiFC) showed that AaPYL9 interacted with AaPP2C1. The P89S, H116A substitution in AaPYL9 as well as G199D substitution or deletion of the third phosphorylation site-like motif in AaPP2C1 abolished this interaction. Furthermore, constitutive expression of AaPP2C1 conferred ABA insensitivity compared with the wild type. In summary, our data reveals that AaPP2C1 is an AaPYL9-interacting partner and involved in the negative modulation of the ABA signaling pathway in A. annua L.
植物激素脱落酸（ABA）在植物发育和环境胁迫响应中发挥着重要作用。此外，ABA还调节药用植物黄花蒿中的青蒿素等次生代谢。尽管早期研究表明ABA受体AaPYL9在ABA诱导的青蒿素含量提高中发挥积极作用，但黄花蒿中ABA信号通路的许多成分仍有待阐明。为了深入了解AaPYL9的功能，我们分离并鉴定了一个与AaPYL9相互作用的蛋白AaPP2C1。AaPP2C1的编码序列编码一个推导的含有464个氨基酸的蛋白质，具有植物A型PP2C的所有特征。转录分析表明，在ABA、盐和干旱处理后，AaPP2C1的表达水平升高。酵母双杂交和双分子荧光互补分析（BiFC）表明AaPYL9与AaPP2C1相互作用。AaPYL9中的P89S、H116A取代以及AaPP2C1中第三个磷酸化位点样基序的G199D取代或缺失消除了这种相互作用。此外，与野生型相比，AaPP2C1的组成型表达赋予了对ABA的不敏感性。总之，我们的数据表明AaPP2C1是AaPYL9相互作用的蛋白，并参与黄花蒿中ABA信号通路的负调控。
