The Ubiquitin Receptor DA1 Regulates Seed and Organ Size by Modulating the Stability of the Ubiquitin-Specific Protease UBP15/SOD2 in Arabidopsis
The Ubiquitin Receptor DA1 Regulates Seed and Organ Size by Modulating the Stability of the Ubiquitin-Specific Protease UBP15/SOD2 in Arabidopsis
复制标题
拟南芥中泛素受体 DA1 通过调节泛素特异性蛋白酶 UBP15/SOD2 的稳定性来调节种子和器官大小
DOI：
10.1105/tpc.114.122663
复制
发表时间：
2014-02-01
期刊：
影响因子：
11.6
通讯作者：
Li, Yunhai
中科院分区：
文献类型：
--
作者：
Du, Liang;Li, Na;Li, Yunhai
尽管器官大小的控制是发育生物学中的一个基本问题，但人们对决定植物种子最终大小的遗传和分子机制知之甚少。我们之前证明泛素受体 DA1 与 E3 泛素连接酶 DA2 和 DA1 (EOD1)/BIG BROTHER 的 ENHANCER1 协同作用，限制拟南芥种子生长。在这里，我们描述了泛素特异性蛋白酶 15 (UBP15)，由 DA1 的 SUPPRESSOR2 (SOD2) 编码，它通过促进胚珠珠被和种子发育中的细胞增殖来调节种子大小。 sod2/ubp15 突变体形成小种子，而 UBP15 的过度表达则增加野生型植物的种子大小。遗传分析表明，UBP15 在与 DA1 共同的途径中发挥拮抗作用，影响种子大小，但其作用独立于 DA2 和 EOD1。进一步的结果表明，DA1 在体外和体内与 UBP15 物理结合，并调节 UBP15 的稳定性。因此，我们的研究结果建立了四种泛素相关蛋白 DA1、DA2、EOD1 和 UBP15 调节种子大小的遗传和分子框架，并表明它们是增加作物种子大小的有希望的目标。
Although the control of organ size is a fundamental question in developmental biology, little is known about the genetic and molecular mechanisms that determine the final size of seeds in plants. We previously demonstrated that the ubiquitin receptor DA1 acts synergistically with the E3 ubiquitin ligases DA2 and ENHANCER1 OF DA1 (EOD1)/BIG BROTHER to restrict seed growth in Arabidopsis thaliana. Here, we describe UBIQUITIN-SPECIFIC PROTEASE15 (UBP15), encoded by SUPPRESSOR2 OF DA1 (SOD2), which acts maternally to regulate seed size by promoting cell proliferation in the integuments of ovules and developing seeds. The sod2/ubp15 mutants form small seeds, while overexpression of UBP15 increases seed size of wild-type plants. Genetic analyses indicate that UBP15 functions antagonistically in a common pathway with DA1 to influence seed size, but does so independently of DA2 and EOD1. Further results reveal that DA1 physically associates with UBP15 in vitro and in vivo and modulates the stability of UBP15. Therefore, our findings establish a genetic and molecular framework for the regulation of seed size by four ubiquitin-related proteins DA1, DA2, EOD1, and UBP15 and suggest that they are promising targets for increasing seed size in crops.