Hugouvieux V, Kwak J M, Schroeder J I
Division of Biology, Cell and Developmental Biology Section, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
Cell. 2001 Aug 24;106(4):477-87. doi: 10.1016/s0092-8674(01)00460-3.
The plant hormone abscisic acid (ABA) regulates important stress and developmental responses. We have isolated a recessive ABA hypersensitive mutant, abh1, that shows hormone specificity to ABA. ABH1 encodes the Arabidopsis homolog of a nuclear mRNA cap binding protein and functions in a heterodimeric complex to bind the mRNA cap structure. DNA chip analyses show that only a few transcripts are down-regulated in abh1, several of which are implicated in ABA signaling. Consistent with these results, abh1 plants show ABA-hypersensitive stomatal closing and reduced wilting during drought. Interestingly, ABA-hypersensitive cytosolic calcium increases in abh1 guard cells demonstrate amplification of early ABA signaling. Thus, ABH1 represents a modulator of ABA signaling proposed to function by transcript alteration of early ABA signaling elements.
植物激素脱落酸（ABA）调控重要的胁迫和发育反应。我们分离出了一个隐性ABA超敏感突变体abh1，它对ABA表现出激素特异性。ABH1编码一种核mRNA帽结合蛋白的拟南芥同源物，并在异二聚体复合物中发挥作用以结合mRNA帽结构。DNA芯片分析表明，在abh1中只有少数转录本下调，其中一些与ABA信号传导有关。与这些结果一致，abh1植株在干旱期间表现出对ABA超敏感的气孔关闭和萎蔫减轻。有趣的是，abh1保卫细胞中对ABA超敏感的胞质钙增加表明早期ABA信号传导得到放大。因此，ABH1代表一种ABA信号传导调节剂，推测其通过改变早期ABA信号元件的转录发挥作用。
