Overexpression of TaVRN1 in Arabidopsis promotes early flowering and alters development
Overexpression of TaVRN1 in Arabidopsis promotes early flowering and alters development
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DOI：
10.1093/pcp/pcm089
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发表时间：
2007-08-01
影响因子：
4.9
通讯作者：
Sarhan, Fathey
中科院分区：
文献类型：
--
作者：
Adam, Helene;Ouellet, Francois;Sarhan, Fathey
TaVRN 1是MADS-box转录因子APETALA 1（AP 1）亚家族的成员，是控制小麦营养生长向生殖生长转变的关键基因。TaVRN 1转录本在冬小麦中的积累可能需要TaVRT 2的下调，TaVRT 2是结合并抑制TaVRN 1启动子的MADS盒因子，以及开花抑制因子TaVRN 2。然而，TaVRN 1作为相变激活剂的分子机制尚不清楚。为了解决这个问题，使用了基因表达和功能研究的组合。RNA原位杂交研究表明，TaVRN 1转录积累在所有分生组织和原基与花发育。在酵母中的相互作用筛选揭示了TaVRN 1与参与植物发育的不同过程的几种蛋白质相互作用，如转录因子、激酶和亲环蛋白。过表达TaVRN 1的拟南芥植物开花早，并表现出不同程度的修改植物结构。异位表达导致AP 1和MAX 4基因的过度表达，这两个基因分别与开花和生长素调控有关。基因表达的诱导可能是由于TaVRN 1与AP 1和MAX 4启动子上存在的CArG基序的结合。相反，过表达TaVRT 2（编码一个推定的开花抑制因子）的拟南芥植物显示出相反的晚花表型。总之，这些数据提供了分子证据，表明TaVRN 1可能在各种过程中具有多效性效应，例如控制腋芽生长，向开花过渡和花器官发育。
TaVRN1, a member of the APETALA1 (AP1) subfamily of MADS-box transcription factors, is a key gene that controls transition from vegetative to reproductive phase in wheat. The accumulation of TaVRN1 transcripts in winter wheat probably requires the down-regulation of TaVRT2, a MADS-box factor that binds and represses the TaVRN1 promoter, and of the flowering repressor TaVRN2. However, the molecular mechanisms by which TaVRN1 functions as an activator of phase transition is unknown. To address this, a combination of gene expression and functional studies was used. RNA in situ hybridization studies showed that TaVRN1 transcripts accumulate in all meristems and primordia associated with flower development. An interaction screen in yeast revealed that TaVRN1 interacts with several proteins involved in different processes of plant development such as transcription factors, kinases and a cyclophilin. Arabidopsis plants overexpressing TaVRN1 flower early and show various levels of modified plant architecture. The ectopic expression causes an overexpression of the AP1 and MAX4 genes, which are associated with flowering and auxin regulation, respectively. The induction of gene expression probably results from the binding of TaVRN1 to CArG motifs present on the AP1 and MAX4 promoters. In contrast, Arabidopsis plants that overexpress TaVRT2, which encodes a putative flowering repressor, show an opposite late flowering phenotype. Together, the data provide molecular evidence that TaVRN1 may have pleiotropic effects in various processes such as control of axillary bud growth, transition to flowering and development of floral organs.