E3泛素连接酶PUBa/b调控拟南芥耐冻性的分子机制

作为重要的环境因子，低温胁迫严重影响植物的生长、作物产量和品质。随着研究的深入，植物响应低温胁迫的分子机理研究取得了一定的进展。E3泛素连接酶介导的蛋白质降解调控植物众多生理过程。然而，关于E3泛素连接酶调控植物低温应答的研究还非常有限。为了研究E3泛素连接酶调控植物低温应答的分子机理，我们前期开展了拟南芥低温相关E3泛素连接酶的筛选，并获得一个冻敏感突变体puba。研究结果表明PUBa与低温负调控因子MYB15存在相互作用。本研究中，我们将通过遗传学、分子生物学、生物化学等方法解析PUBa及其同源基因PUBb在植物响应低温胁迫中的作用，深入研究PUBa/b与MYB15互作的生物学意义，揭示PUBa/b蛋白的分子调控机制。研究将阐明E3泛素连接酶在植物响应低温胁迫中的作用提供分子基础，为培育抗低温作物提供重要的基因资源。

Cold stress is one of the key environmental factors that adversely affect plant growth, productivity and quality. Emerging evidence indicated that E3 ubiquitin ligases modulate numerous physiological processes in plants. Although some progress has been made in the study of the mechanisms of plant response to cold stress, the details of E3 ubiquitin ligases in regulating plant cold stress response are very limited. To resolve this issue, we previously performed genetic screening with a freezing tolerance assay, and found that U-box type E3 ubiquitin ligase PUBa positively regulates plant freezing tolerance. Moreover, PUBa interacts with cold negative regulator MYB15. In this project, we will dissect the functions of PUBa and its homologous gene PUBb in regulating plant freezing tolerance using genetic, molecular and biochemical approaches. Moreover, we will deeply investigate the biological significance of the interaction between PUBa/b and MYB15. The molecular mechanism underlying PUBa/b regulation will be also explored. This study will shed more light on the understanding of function of E3 ubiquitin ligases in regulating plant response to cold stress, and provide useful genetic resource for breeding of cold-tolerant varieties.