Yamauchi Shota, Takemiya Atsushi, Sakamoto Tomoaki, Kurata Tetsuya, Tsutsumi Toshifumi, Kinoshita Toshinori, Shimazaki Ken-Ichiro
Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan (S.Y., A.T., T.T., K.S.); Plant Global Education Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan (T.S., Te.K.); and Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8602, Japan (To.K.).
Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan (S.Y., A.T., T.T., K.S.); Plant Global Education Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan (T.S., Te.K.); and Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8602, Japan (To.K.)
Plant Physiol. 2016 Aug;171(4):2731-43. doi: 10.1104/pp.16.01581. Epub 2016 Jun 3.
Stomata open in response to a beam of weak blue light under strong red light illumination. A blue light signal is perceived by phototropins and transmitted to the plasma membrane H(+)-ATPase that drives stomatal opening. To identify the components in this pathway, we screened for mutants impaired in blue light-dependent stomatal opening. We analyzed one such mutant, provisionally named blus2 (blue light signaling2), and found that stomatal opening in leaves was impaired by 65%, although the magnitude of red light-induced opening was not affected. Blue light-dependent stomatal opening in the epidermis and H(+) pumping in guard cell protoplasts were inhibited by 70% in blus2 Whole-genome resequencing identified a mutation in the AHA1 gene of the mutant at Gly-602. T-DNA insertion mutants of AHA1 exhibited a similar phenotype to blus2; this phenotype was complemented by the AHA1 gene. We renamed blus2 as aha1-10 T-DNA insertion mutants of AHA2 and AHA5 did not show any impairment in stomatal response, although the transcript levels of AHA2 and AHA5 were higher than those of AHA1 in wild-type guard cells. Stomata in ost2, a constitutively active AHA1 mutant, did not respond to blue light. A decreased amount of H(+)-ATPase in aha1-10 accounted for the reduced stomatal blue light responses and the decrease was likely caused by proteolysis of misfolded AHA1. From these results, we conclude that AHA1 plays a major role in blue light-dependent stomatal opening in Arabidopsis and that the mutation made the AHA1 protein unstable in guard cells.
在强光红光照射下，气孔会对一束弱蓝光作出反应而张开。蓝光信号被向光素感知，并传递到驱动气孔张开的质膜H(+) -ATP酶。为了确定该信号通路中的组分，我们筛选了蓝光依赖型气孔张开受损的突变体。我们分析了一个这样的突变体，暂命名为blus2（蓝光信号转导2），发现叶片中的气孔张开受到65%的抑制，尽管红光诱导的张开幅度不受影响。在blus2中，表皮蓝光依赖型气孔张开和保卫细胞原生质体中的H(+) 泵出受到70%的抑制。全基因组重测序鉴定出该突变体AHA1基因的甘氨酸602位点发生了突变。AHA1的T-DNA插入突变体表现出与blus2相似的表型；该表型被AHA1基因互补。我们将blus2重新命名为aha1-10。AHA2和AHA5的T-DNA插入突变体在气孔反应中未表现出任何损伤，尽管在野生型保卫细胞中AHA2和AHA5的转录水平高于AHA1。ost2（一种组成型活性AHA1突变体）中的气孔对蓝光无反应。aha1-10中H(+) -ATP酶数量的减少导致气孔蓝光反应减弱，这种减少可能是由错误折叠的AHA1的蛋白水解引起的。从这些结果中，我们得出结论，AHA1在拟南芥蓝光依赖型气孔张开中起主要作用，并且该突变使保卫细胞中的AHA1蛋白不稳定。
