木材主要由次生细胞壁组成，它的形成是一个严格受基因编码的多层网络调控的复杂动态生物学过程。CCCH型锌指蛋白是一类特殊的锌指蛋白，它在转录水平和转录后水平上参与植物生长发育的调控和逆境胁迫的响应。然而，迄今很少报道CCCH锌指蛋白参与次生木质部的形成机制。我们前期研究表明，杨树PdC3H17和PdC3H18是两个典型的CCCH锌指蛋白；它们是通过调控细胞壁合成基因的大量表达来参与次生木质部的形成；均能被PdMYB3和PdMYB21直接调控；提出它们可能是次生木质部形成的调控途径之一。基于以上研究，本项目一方面利用酵母双杂交等技术鉴定PdC3H17/18在次生木质部形成过程中的互作蛋白，揭示它们在蛋白质水平上的协同调控作用；另一方面运用基因芯片和ChIP/RIP-Seq等技术挖掘它们所调控的下游靶标，解析它们在次生木质部形成过程中的分子调控通路，为未来利用基因工程改良木材奠定基础。

Wood is mainly made of secondary cell walls, whose formation is controlled by a multilevel regulation network. Plant CCCH zinc finger proteins comprise a large family, play diverse roles in developmental and adaptive processes at both the transcriptional and posttranscriptional levels. However, few plant CCCH proteins have been functionally studied in the regulation of secondary wall formation until now. Recently, we have characterized two poplar CCCH zinc finger proteins PdC3H17 and PdC3H18 and found that they are the targets of PdMYB3 and PdMYB21, and positively regulate secondary cell wall formation through regulating the expression of cellulose, xylan and lignin biosynthetic genes in poplar, suggesting that they are two additional components in the regulatory network of secondary xylem formation in poplar. Based on the above results, this project aims to further identify the downstream targets and interacting proteins of these two proteins using the microarray, ChIP/RIP-Seq and Y2H methods, and finally clarify their regulatory mechanism during secondary xylem formation. This project will provide new insight into the components of the complex regulatory network of xylem development and therefore mark another important step toward the dissection of the molecular network that regulates secondary wall formation in plants, which may facilitate genetic engineering of wood quality and quantity.