Molecular mechanism of seed maturation, dormancy and germination using viviparous mutants

脱落酸(ABA)是一种重要的植物激素，调节种子成熟、休眠和萌发等多种生理过程。SRK2D、SRK2E和SRK2I是拟南芥中ABA激活的冗余SNF1相关蛋白激酶2(SnRK2s)。SnRK2蛋白激酶的三个突变体(srk2d、srk2e、srk2i)表现出胎生萌发。在种子发育过程中对干燥敏感，表现出严重的生长缺陷。与野生型种子相比，它表现出休眠解除，对ABA不敏感，种子ABA含量升高。基因芯片实验表明，参与ABA信号转导的SRK2D、SRK2E和SRK2I蛋白激酶通过广泛的基因表达调控对种子发育、休眠和萌发起着至关重要的作用。

Abscisic acid(ABA) is an important phytohormone regulating various physiological processes including seed maturation, dormancy and germination. SRK2D, SRK2E and SRK2I are redundant ABA-activated SNF1-related protein kinases 2(SnRK2s) in Arabidopsis thaliana. The triple mutant of the SnRK2 protein kinases(srk2d srk2e srk2i) showed viviparous germination. It was sensitive to desiccation and showed severe growth defects during seed development. It exhibited a loss of dormancy, strong ABA-insensitivity, and elevated seed ABA content relative to wild-type seeds. The triple mutant had greatly reduced phosphorylation activity in in-gel kinase experiments using bZIP transcription factors including ABI5.Microarray experiments indicate that SRK2D, SRK2E and SRK2I protein kinases involved in ABA signaling are essential for the control of seed development, dormancy and germination through the extensive control of gene expression.