拟南芥类受体蛋白RLP11和RLP12参与CLE19多肽调控根近端分生组织发育的功能研究

Receptor-like proteins (RLP) are present in many plant species with a total of 57 members in Arabidopsis. However, only a few RLPs have been assigned a function, suggesting that a high level of functional redundancy among the RLPs. To circumvent this situation, RNA interference (RNAi) to target the expression of multiple RLP genes simultaneously was employed. We found that the transgenic plants of RLP11/12 RNAi which is predicted to silence both RLP11 and RLP12, failed to respond to the CLE19 peptide treatment. In addition, RLP11 and RLP12 exhibit a peak expression level in proximal meristem of root apex. These findings collectively suggest that RLP11 and RLP12 are involved in the CLE19 peptide signaling to regulate the root apical meristem. In this study, we firstly assess the role of RLP11 and RLP12 by further phenotypic examination of RLP11/12 RNAi lines and transgenic plants overexpressing RLP11 and RLP12. In order to decipher the relationship among RLP11/12, CLV2, CRN and RPK2, the genetic interaction will examined with high-order mutants. To extend our genetic studies, we next will investigate biochemically whether RLP11/12 associates with CLV2-CRN and RPK2 complexes. Using different auxin distribution and transport marker lines, the relationship between RLP11/12-mediated and auxin-mediated signaling pathways will be investigated to determine the crosstalk between the CLE peptide and auxin. It will be intriguing to identify the molecular mechanism by which auxin signal is integrated with CLE19 signal to regulate root proximal meristem development. This proposal will advance our understanding of the function of RLP11/12 in regulation of proximal meristem and the extent to how RLP11/12 modulate proximal meristem.

类受体蛋白RLP广泛存在于高等植物中，其家族在拟南芥中有57个成员。但是RLP家族的功能冗余阻碍了研究进展，因此功能已知的RLP很少。我们前期研究发现采用RNAi同时特异性地沉默两个串联重复的RLP基因RLP11和RLP12的植株的根对CLE19多肽处理呈现不敏感，并且RLP11和RLP12在根近端分生组织中高表达，说明RLP11和RLP12参与了CLE19信号在根近端分生组织维持与分化的调控。本项目拟通过对RLP11/12 RNAi及过表达植株的表型分析明确它们在根近端分生组织发育中的功能；分析RLP11/12与CLV2、CRN和RPK2的遗传关系以及其蛋白间的相互作用，阐明RLP11/12与这些蛋白在调控网络中的关系；分析RLP11/12参与根近端分生组织的信号通路与生长素信号通路是否相互作用。期望通过这些研究阐明RLP11和RLP12参与CLE19多肽调控根近端分生组织发育的功能。

类受体蛋白RLP广泛存在于高等植物中，其家族在拟南芥中有57个成员。但是RLP家族的功能冗余阻碍了研究进展，因此功能已知的RLP很少。我们的研究发现采用RNAi同时特异性地沉默两个串联重复的RLP基因RLP11和RLP12的植株的根对CLE19多肽处理呈现不敏感，并且RLP11和RLP12在根近端分生组织中高表达，说明RLP11和RLP12参与了CLE19信号在根近端分生组织维持与分化的调控。在clv2-1的突变体中中分别过表达RLP11和RLP12可以互补clv2-1的表型，这说明RLP11和RLP12与CLV2蛋白功能的相似。然而，rlp11和rlp12的T-DNA插入突变体并未出现类似与clv2突变体的表型。这些研究说明RLP11/RLP12与CLV2的功能差别主要是源于基因表达的差异。对RLP11/12 RNAi及过表达植株的幼苗根部分析并未发现异常，说明可能还有其他功能冗余基因参与。RLP11/12 RNAi植株与生长素分布于运输的标记植物进行了杂交，而且本研究构建了用于研究RLP11和RLP12与其他已知受体蛋白/激酶相互作用的表达载体。本项目通过对 RLP11/12 RNAi及RLP11和RLP12过表达植株的表型分析、RLP11和RLP12的表达，以及它们的T-DNA插入突变体/RNAi植株/超表达植株对CLE19的响应等试验了明确它们在根近端分生组织发育中的功能，期望通过这些研究阐明RLP11和RLP12参与CLE19多肽调控根近端分生组织发育的功能。