杨树泛素受体PdDA1s介导泛素蛋白酶体途径调控木材形成的分子机制

木材形成过程由若干个连续阶段组成，其中维管形成层细胞的活性对于木材形成至关重要，也是决定木材最终产量的关键因素。然而，尽管目前在维管形成层活性的转录调控研究方面取得了较大进展，但在蛋白翻译后水平的调控机制仍知之甚少。我们前期研究表明，杨树泛素受体DA1s负调控维管形成层细胞分裂与木质部分化，同时发现DA1s可以与维管形成层调控关键因子WOX4互作，进一步研究发现DA1s可能通过泛素化修饰的肽酶活性来影响WOX4蛋白的稳定性，继而影响维管形成层活性及木材形成。在此基础上，本项目将结合组学、生化及遗传分析手段，深入研究杨树DA1s的生物学功能，鉴定其可能的作用靶标，阐明DA1s通过泛素蛋白酶体途径影响WOX4蛋白稳定性调控木材形成的分子机制，这将进一步完善木材形成的分子调控网络，为今后木材形成调控机制的研究提供新颖的视角，也为利用基因工程手段定向遗传改良木材产量奠定基础。

Wood formation consists of several consecutive stages, among them, the vascular cambium activity is critical and is the key factor to determine the final wood yield. However, although great progress has been made in the study of transcriptional regulation of vascular cambium activity, little is known about the regulatory mechanism at the post translation level. Our previous studies showed that poplar ubiquitin receptor DA1s negatively regulated vascular cambium cell division and xylem differentation. It was also showed that DA1s interacted with WOX4, a key regulator of vascular cambium. Further studies showed that DA1s may affect the stability of WOX4 protein through the ubiquitination-dependent modification of the peptidase activity, which in turn affected vascular cambium activity and wood formation. Based on this, combining the methods of omics, biochemistry and genetic analyses, this project will deeply study the biological function of poplar DA1s genes, identify its possible targets, and clarify the molecular mechanism that DA1s affect the stability of WOX4 protein through the ubiquitin proteasome pathway during wood formation. This will further improve the molecular regulatory network of wood formation, provide a new perspective for the future research on the regulation mechanism of wood formation, and also provide the theoretical basis for genetic engineering of wood yield in tree species.