Transcription Factors SOD7/NGAL2 and DPA4/NGAL3 Act Redundantly to Regulate Seed Size by Directly Repressing KLU Expression in Arabidopsis thaliana
Transcription Factors SOD7/NGAL2 and DPA4/NGAL3 Act Redundantly to Regulate Seed Size by Directly Repressing KLU Expression in Arabidopsis thaliana
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DOI：
10.1105/tpc.114.135368
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发表时间：
2015-03
期刊：
影响因子：
11.6
通讯作者：
Yueying Zhang;L. Du;Ran Xu;Rongfeng Cui;J. Hao;Caixia Sun;Yunhai Li
中科院分区：
文献类型：
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作者：
Yueying Zhang;L. Du;Ran Xu;Rongfeng Cui;J. Hao;Caixia Sun;Yunhai Li
SOD7/NGAL2和DPA4/NGAL3两个转录因子通过抑制KLU的表达来调节种子和器官的大小，这表明它们是作物改良的有希望的靶点。虽然种子大小是植物最重要的农艺性状之一，但决定种子最终大小的遗传和分子机制在很大程度上是未知的。我们之前发现泛素受体DA1是种子大小的负调节因子，而拟南芥DA1 -1突变体产生的种子比野生型大。在这里，我们描述了一个B3结构域转录抑制因子ngatha样蛋白（NGAL2），由da1-1抑制因子（SOD7）编码，其母系作用是通过限制胚珠被和种子发育中的细胞增殖来调节种子大小。过表达SOD7会显著降低野生型植物的种子大小，而同时破坏SOD7及其与发育相关的PcG靶蛋白APEX4 （DPA4/NGAL3）会增加种子大小。遗传分析表明，SOD7和DPA4与种子大小调节剂KLU共同调控种子生长，但独立于DA1。进一步的研究结果表明，SOD7在体外和体内均可直接结合KLUH启动子（KLU），抑制KLU的表达。因此，我们的研究结果揭示了SOD7、DPA4和KLU调控种子大小的遗传和分子机制，并表明它们是作物种子大小改良的有希望的靶点。
Two transcription factors, SOD7/NGAL2 and DPA4/NGAL3, regulate seed and organ size by repressing the expression of KLU, suggesting that they are promising targets for crop improvement. Although seed size is one of the most important agronomic traits in plants, the genetic and molecular mechanisms that set the final size of seeds are largely unknown. We previously identified the ubiquitin receptor DA1 as a negative regulator of seed size, and the Arabidopsis thaliana da1-1 mutant produces larger seeds than the wild type. Here, we describe a B3 domain transcriptional repressor NGATHA-like protein (NGAL2), encoded by the suppressor of da1-1 (SOD7), which acts maternally to regulate seed size by restricting cell proliferation in the integuments of ovules and developing seeds. Overexpression of SOD7 significantly decreases seed size of wild-type plants, while the simultaneous disruption of SOD7 and its closest homolog DEVELOPMENT-RELATED PcG TARGET IN THE APEX4 (DPA4/NGAL3) increases seed size. Genetic analyses indicate that SOD7 and DPA4 act in a common pathway with the seed size regulator KLU to regulate seed growth, but do so independently of DA1. Further results show that SOD7 directly binds to the promoter of KLUH (KLU) in vitro and in vivo and represses the expression of KLU. Therefore, our findings reveal the genetic and molecular mechanisms of SOD7, DPA4, and KLU in seed size regulation and suggest that they are promising targets for seed size improvement in crops.