The MicroRNA159-Regulated GAMYB-like Genes Inhibit Growth and Promote Programmed Cell Death in Arabidopsis
The MicroRNA159-Regulated GAMYB-like Genes Inhibit Growth and Promote Programmed Cell Death in Arabidopsis
复制标题
DOI：
10.1104/pp.110.160630
复制
发表时间：
2010-10-01
期刊：
影响因子：
7.4
通讯作者：
Millar, Anthony A.
中科院分区：
文献类型：
--
作者：
Alonso-Peral, Maria M.;Li, Junyan;Millar, Anthony A.
microRNA159（miR159）家族抑制保守的GAMYB样基因，所述基因编码R2R3 MYB结构域转录因子，所述R2R3 MYB结构域转录因子涉及花药和萌发种子中的赤霉素（GA）信号传导。在拟南芥中，两个主要的miR159家族成员miR159 a和miR159 b在功能上对两个GamyB样基因MYB 33和MYB 65具有特异性。这些转录因子已被证明参与花药发育，但有不同的报告，他们在促进开花的作用，很少有人知道他们在种子萌发的功能。为了了解这一通路的功能，我们鉴定了这些类GamyB基因控制的基因和过程。首先，我们证明了miR159在营养组织中完全抑制MYB33和MYB65。我们表明，GA不释放这种抑制，这些转录因子不需要开花或生长。相比之下，在miR159的情况下，营养组织中MYB33和MYB65的失调上调了在种子萌发期间诱导的糊粉层和GA中高度表达的基因。表明这些基因是GAMYB样调节的，它们的表达在myb33.myb65.myb101种子中减少。糊粉液泡化，GA介导的程序性细胞死亡过程所需的发芽，在这些种子受损。最后，营养组织中MYB 33和MYB 65的失调通过减少细胞增殖来抑制生长。因此，我们得出结论，miR159作为一个分子开关，只允许在花药和种子中的GamyB样基因的表达。在种子中，这些转录因子参与GA诱导的糊粉层发育和死亡所需的途径。
The microRNA159 (miR159) family represses the conserved GAMYB-like genes that encode R2R3 MYB domain transcription factors that have been implicated in gibberellin (GA) signaling in anthers and germinating seeds. In Arabidopsis (Arabidopsis thaliana), the two major miR159 family members, miR159a and miR159b, are functionally specific for two GAMYB-like genes, MYB33 and MYB65. These transcription factors have been shown to be involved in anther development, but there are differing reports about their role in the promotion of flowering and little is known about their function in seed germination. To understand the function of this pathway, we identified the genes and processes controlled by these GAMYB-like genes. First, we demonstrate that miR159 completely represses MYB33 and MYB65 in vegetative tissues. We show that GA does not release this repression and that these transcription factors are not required for flowering or growth. By contrast, in the absence of miR159, the deregulation of MYB33 and MYB65 in vegetative tissues up-regulates genes that are highly expressed in the aleurone and GA induced during seed germination. Confirming that these genes are GAMYB-like regulated, their expression was reduced in myb33.myb65.myb101 seeds. Aleurone vacuolation, a GA-mediated programmed cell death process required for germination, was impaired in these seeds. Finally, the deregulation of MYB33 and MYB65 in vegetative tissues inhibits growth by reducing cell proliferation. Therefore, we conclude that miR159 acts as a molecular switch, only permitting the expression of GAMYB-like genes in anthers and seeds. In seeds, these transcription factors participate in GA-induced pathways required for aleurone development and death.