MYB转录因子RH1和RH2协同调控蒺藜苜蓿叶痕形成的分子机理解析

自然界中千奇百趣的生物图案形成的奥秘一直是生物学研究领域的热点问题。植物叶片上形成的特异性斑点或条纹状色素图案被称为叶痕(Leaf marking)，鲜艳的叶痕不仅增加了植物形态的多样性，同时被认为具有警戒色作用，但目前关于植物叶痕性状形成的分子基础仍不清楚。申请人前期利用具有典型花青素红圈包围黄绿色中心叶痕的蒺藜苜蓿R108为实验材料，获得一个花青素斑痕变大增强的半显性突变体red heart1 (rh1d)。研究发现rh1d的叶痕表型是由于MYB转录因子基因RH1高表达所导致。此外，我们发现RH1的同源基因RH2负调控蒺藜苜蓿叶痕花青素合成以及RH1的表达，表明蒺藜苜蓿的叶痕性状受到RH1和RH2的共同调控。本项目在此工作基础上，拟通过系统解析MYB同源基因RH1和RH2协同调控蒺藜苜蓿叶痕形成的分子机理，为揭示植物特异性色素图案形成的调控机制和阐明生物复杂图案形成的奥秘提供理论基础。

The visually striking patterns of diverse organisms in nature have fascinated biologists for centuries. Patterned leaf coloration (leaf marking) in plants generates remarkable diversity and is potentially aposematic, but the underlying mechanisms remain largely unclear. Using the Medicago truncatula R108 anthocyanin leaf marking as a model, our lab's previous study found that the classic M. truncatula leaf anthocyanin spot trait depends on a novel MYB activator, RED HEART1 (RH1), by characterizing a dominant leaf marking mutant red heart1 (rh1d) with enlarged and enhanced leaf anthocyanin spots. Furthermore, we found that a paralog of RH1, RH2, exerts an opposite effect on anthocyanin biosynthesis of M. truncatula leaf markings while also repressing RH1 expression, suggesting that both RH1 and RH2 are required for fine-tuning M.truncatula leaf marking formation. On the basis of above findings, this proposal intends to demonstrate the RH1-RH2-mediated regulatory paradigm for leaf anthocyanin markings in M. truncatula, which will provide insights into understanding the regulatory control of complex patterned pigmentation in diverse organisms in nature.