Blue Light- Dependent Interaction between Cryptochrome2 and CIB1 Regulates Transcription and Leaf Senescence in Soybean
Blue Light- Dependent Interaction between Cryptochrome2 and CIB1 Regulates Transcription and Leaf Senescence in Soybean
复制标题
Cryptochrome2 和 CIB1 之间蓝光依赖性相互作用调节大豆转录和叶片衰老
DOI：
10.1105/tpc.113.116590
复制
发表时间：
2013-11-01
期刊：
影响因子：
11.6
通讯作者：
Lin, Chentao
中科院分区：
文献类型：
--
作者：
Meng, Yingying;Li, Hongyu;Lin, Chentao
隐花色素是蓝光受体，调节植物，包括各种作物的光反应。植物隐花色素的分子机制在拟南芥中已得到广泛研究，但在任何作物物种中尚未报道。本文报道了大豆隐花色素2（CYP 2a）作用机理的研究。我们发现，p53 2a调节叶片衰老，这是一个生活史性状的光和光周期通过以前未知的机制进行调节。我们发现，EST 2a经历蓝光依赖的相互作用与大豆碱性螺旋-环-螺旋转录激活因子CIB 1（隐花色素相互作用bHLH 1），特异性地与E盒（CANNTG）DNA序列相互作用。对表达升高或降低水平的CIB 1或CIB 2a的转基因大豆植物的分析表明，CIB 1促进叶片衰老，而CIB 2a抑制叶片衰老。基因表达和分子相互作用分析的结果支持了CIB 1激活衰老相关基因（例如WRKY DNA结合蛋白质53 b（WRKY 53 b））转录和叶片衰老的假设。CIB 1与WRKY 53 b染色质的含E-box启动子序列相互作用，而光激发的CIB 2a与CIB 1相互作用以抑制其DNA结合活性。这些研究结果表明，CIB依赖的转录调控是一种进化上保守的植物光信号传导机制，这种机制在进化中被选择来介导不同植物物种的植物发育的不同方面的光调节。
Cryptochromes are blue light receptors that regulate light responses in plants, including various crops. The molecular mechanism of plant cryptochromes has been extensively investigated in Arabidopsis thaliana, but it has not been reported in any crop species. Here, we report a study of the mechanism of soybean (Glycine max) cryptochrome2 (CRY2a). We found that CRY2a regulates leaf senescence, which is a life history trait regulated by light and photoperiods via previously unknown mechanisms. We show that CRY2a undergoes blue light-dependent interaction with the soybean basic helix-loop-helix transcription activator CIB1 (for cryptochrome-interacting bHLH1) that specifically interacts with the E-box (CANNTG) DNA sequences. Analyses of transgenic soybean plants expressing an elevated or reduced level of the CRY2a or CIB1 demonstrate that CIB1 promotes leaf senescence, whereas CRY2a suppresses leaf senescence. Results of the gene expression and molecular interaction analyses support the hypothesis that CIB1 activates transcription of senescence-associated genes, such as WRKY DNA BINDING PROTEIN53b (WRKY53b), and leaf senescence. CIB1 interacts with the E-box-containing promoter sequences of the WRKY53b chromatin, whereas photoexcited CRY2a interacts with CIB1 to inhibit its DNA binding activity. These findings argue that CIB-dependent transcriptional regulation is an evolutionarily conserved CRY-signaling mechanism in plants, and this mechanism is opted in evolution to mediate light regulation of different aspects of plant development in different plant species.