Plant Journal:中科院遗传所薛勇彪研究组揭示显花植物自交不亲和
2016年8月29日，国际植物学权威期刊《The plant Journal》在线发表了中国科学院遗传与发育生物学研究所薛勇彪研究组揭示显花植物自交不亲和特异性识别机制研究进展，薛勇彪研究组李俊慧博士为该论文的第一作者，薛勇彪研究员为论文通讯作者。
自交不亲和性是广泛存在于显花植物中的一种重要的自己/异己识别系统。在大多数物种中，自交不亲和性是由一个单一的复等位基因位点S位点所控制。在茄科，蔷薇科和车前科中，S位点编码一个S-核酸酶和一簇SLF(S-locus F-box)蛋白，二者分别控制花柱和花粉的自交不亲和性。前人的研究表明二者的相互作用决定了它们的识别特异性，但是它们之间的相互作用力却不清楚。
研究人员通过对茄科植物杂交矮牵牛(Petunia hybrida)自交不亲和性中花粉和花柱因子的相互作用的研究，发现花粉因子SLF和花柱因子S-核酸酶通过表面静电势的“同性相斥，异性相吸”的物理机制参与自交不亲和的特异性决定。有趣的是，突变SLF蛋白C端一个氨基酸可以反转了该位点的表面静电势进而改变了花粉S基因的特异性。该研究揭示了表面静电势是胞质内SLF和S-RNase蛋白识别的主要物理作用力，为被子植物中胞质内蛋白自己/异己识别的机制提供了新的思路(图1)。
图示：SLF和S-RNAse表面静电势“同性相斥，异性相吸”的相互作用模式图
原文链接：
Electrostatic potentials of the S-locus F-box proteins contribute to the pollen Sspecificity in self-incompatibility in Petunia hybrida
原文摘要：
Self-incompatibility (SI) is a self/non-self discrimination system widely found in angiosperms and, in many species, is controlled by a single polymorphic S-locus. In the Solanaceae, Rosaceae and Plantaginaceae, the S-locus encodes a single S-RNase and a cluster of S-locus F-box (SLF) proteins to control the pistil and pollen expression of SI, respectively. Previous studies have shown that their cytosolic interactions determine their recognition specificity, but the physical force between their interactions remains unclear. In this study, we show that the electrostatic potentials of SLF contribute to the pollen S specificity through a physical mechanism of “like charges repel and unlike charges attract” between SLFs and S-RNases inPetunia hybrida. Strikingly, alteration of a single C-terminal amino acid of SLF reversed its surface electrostatic potentials and subsequently the pollen S specificity. Collectively, our results reveal that the electrostatic potentials act as a major physical force between cytosolic SLFs and S-RNases, providing a mechanistic insight into the self/non-self discrimination between cytosolic proteins in angiosperms.
作者：薛勇彪
