Membrane-associated transcription factor peptidase, site-2 protease, antagonizes ABA signaling in Arabidopsis.
Membrane-associated transcription factor peptidase, site-2 protease, antagonizes ABA signaling in Arabidopsis.
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DOI：
10.1111/nph.13436
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发表时间：
2015-10
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影响因子：
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通讯作者：
Shun-Fan Zhou;Le Sun;A. E. Valdés;P. Engström;Ze-Ting Song;Sun-Jie Lu;Jian-Xiang Liu
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文献类型：
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作者：
Shun-Fan Zhou;Le Sun;A. E. Valdés;P. Engström;Ze-Ting Song;Sun-Jie Lu;Jian-Xiang Liu
脱落酸在维持种子休眠中起重要作用，赤霉素（GA）等植物激素可拮抗脱落酸（阿坝）促进种子萌发。然而，阿坝信号是如何从休眠到萌发的过渡过程中脱敏仍然知之甚少。我们从功能上表征了膜相关转录因子肽酶（位点2蛋白酶（S2 P））在拟南芥种子萌发期间脱落阿坝信号传导中的作用。遗传分析表明，S2 P的功能丧失赋予高阿坝敏感性在种子萌发过程中，和表达的激活形式的膜相关转录因子bZIP 17，其中跨膜结构域和内质网（ER）腔面向C-末端被删除，在S2 P突变体拯救其ABA敏感的表型。MYC和绿色荧光蛋白（GFP）标记的bZIP 17被加工并响应于阿坝处理从ER易位到细胞核。此外，编码阿坝信号负调节因子的基因，例如转录因子ATHB 7及其靶基因HAB 1、HAB 2、HAI 1和AHG 3，在野生型种子中在阿坝处理后上调;这种上调在S2 P突变体的种子中被削弱。我们的研究结果表明，S2 P脱敏阿坝信号在种子萌发过程中，通过调节膜相关转录因子bZIP 17的激活，从而控制基因的表达水平编码的阿坝信号负调节。
Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood. We functionally characterized the role of membrane-associated transcription factor peptidase, site-2 protease (S2P), in ABA signaling during seed germination in Arabidopsis. Genetic analysis showed that loss-of-function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane-associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen-facing C-terminus were deleted, in the S2P mutant rescued its ABA-sensitive phenotype. MYC and green fluorescent protein (GFP)-tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up-regulated in seeds of the wild-type upon ABA treatment; this up-regulation was impaired in seeds of S2P mutants. Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane-associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling.