Re-induction of the cell cycle in the Arabidopsis post-embryonic root meristem is ABA-insensitive, GA-dependent and repressed by KRP6.
Re-induction of the cell cycle in the Arabidopsis post-embryonic root meristem is ABA-insensitive, GA-dependent and repressed by KRP6.
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DOI：
10.1038/srep23586
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发表时间：
2016-03-29
影响因子：
4.6
通讯作者：
Bassel GW
中科院分区：
文献类型：
--
作者：
Nieuwland J;Stamm P;Wen B;Randall RS;Murray JA;Bassel GW
种子萌发后的播种需要激活根分生组织来促进初生根的生长。研究了拟南芥种子萌发过程中根分生组织激活的激素和遗传调控。在最佳条件下，胚根细胞分裂只发生在萌发完成后，需要从头合成GA。当ABA阻断萌发完成时，这些不发芽的种子发生胚根伸长和细胞分裂。相反，在ga限制条件下，aba不敏感突变体在没有根分生组织激活和生长的情况下完成萌发。因此，胚根分生组织的激活和扩展可以独立于萌发发育过渡的完成而发生。细胞周期调节因子KRP6部分抑制ga依赖的细胞周期激活。krp6突变体种子的萌发速度更快，在剂量-反应试验中对ABA略有不敏感，但对GA合成抑制剂PAC也敏感。这些相互冲突的表型表明，在发芽的拟南芥种子中，细胞周期使GA和ABA反应不偶联，krp6在GA的下游作用，抑制萌发过程中有丝分裂细胞周期的激活。
Seeding establishment following seed germination requires activation of the root meristem for primary root growth. We investigated the hormonal and genetic regulation of root meristem activation during Arabidopsis seed germination. In optimal conditions, radicle cell divisions occur only after the completion of germination and require de novo GA synthesis. When the completion of germination is blocked by ABA, radicle elongation and cell divisions occurred in these non-germinating seeds. Conversely under GA-limiting conditions, ABA-insensitive mutants complete germination in the absence of radicle meristem activation and growth. Radicle meristem activation and extension can therefore occur independently of completion of the developmental transition of germination. The cell cycle regulator KRP6 partially represses GA-dependent activation of the cell cycle. Germination of krp6 mutant seeds occurs more rapidly, is slightly insensitive to ABA in dose-response assays, but also hypersensitive to the GA synthesis inhibitor PAC. These conflicting phenotypes suggest the cell cycle uncouples GA and ABA responses in germinating Arabidopsis seeds, and that KRP6 acts downstream of GA to inhibit mitotic cell cycle activation during germination.