植物激素脱落酸受体偶联途径研究进展

Recent advances in phytohormone abscisic acid receptor–coupled pathway

脱落酸(ABA)是传统的“五大”植物激素之一。目前已知ABA受体偶联途径主要由受体PYR1/PYLs/RCARs蛋白、A分支蛋白磷酸酶PP2C、蛋白激酶SnRK2组成,主要通过激活或抑制SnRK2,实现ABA信号输出的“开”和“关”。在没有ABA时,PP2C去磷酸化并抑制SnRK2。胁迫诱导ABA产生后,ABA与受体形成复合体,结合并抑制PP2C,使SnRK2从抑制状态释放出来。近年发现的B亚组RAF蛋白激酶可以磷酸化并重新激活SnRK2,启动下游ABA信号途径。本文主要综述了ABA受体偶联核心信号途径组分及其调控机制,介绍了近年这一研究领域的主要进展。

Abscisic acid(ABA) is one of the five “classical” plant hormones.The ABA receptor–coupled core signaling pathway mainly composes ABA receptor PYR1/PYLs/RCARs,clade A PP2C protein phosphatases,and protein kinase SnRK2s.Mainly though activating or inhibiting SnRK2 kinase,these components turn “on” or “off” downstream ABA response.In the absence of ABA,PP2Cs bind to and inhibit SnRK2s.Stress induces the accumulation of ABA,and ABA binds to its receptors and inhibits PP2Cs,releasing SnRK2s from inhibition.Recent studies suggest that B subgroup RAF kinases phosphorylate and reactivate the dephosphorylated inactive SnRK2s and initiate ABA signaling.In this review,we summarize core components in ABA receptor–coupled core signaling pathway and mainly focus on the recent progress in this field.