2008年11月27日，中科院遗传与发育生物学研究所所长、国家973计划“水稻功能基因组学研究”项目首席科学家薛勇彪研究员应邀访问研究所。薛所长和部分实验室主任进行了交流并举办学术讲座，讲座题目为：A Life or Death Decision: Molecular control of S-RNase-based self-incompatibility in flowering plants。周俭民博士主持讲座。

Abstract:

In many flowering plants self-fertilization is prevented by an intraspecific reproductive barrier known as self-incompatibility (SI). Among the various SI systems, gametophytic SI (GSI) found in the Solanaceae, Plantaginaceae and Rosaceaeis believed to be the most common type, in which the specificity of SI response is controlled by a single multiallelic self-incompatibility (S)-locus, which is organized in a haplotype manner and carries at least two genes determining the self and non-self pollen recognition specificity: S-RNase (S-ribonucleases) expressed in pistil (pistil S) and SLF (S-Locus F-box) /SFB(S-haplotype-specific F-box) genes in pollen (pollen S). S-RNases have been shown to enter the pollen tubes without allelic specificity and appear to function as cytotoxin to specifically inhibit the growth of the self-pollen tube. However, the precise role of the SLF protein is largely unknown. We have identified a pollen-specific novel SKP1-like protein (SSK1, SLF-interacting SKP1-like1) and found that SSK1 serves as a specific adaptor in a SCF^SLF complex. Substantial reduction of SSK1 expression level does not impair the pollen tube growth in SI-defective styles, but results in pollen inhibition in cross-pollination of functional SI-styles, suggesting that it is required for cross pollen compatibility. Our results indicate that the pollen S determinant contributes to inhibiting, rather than maintaining the S-RNase activity, at least in solanaceous plants. In addition, we also show that S-RNases are specifically ubiquitinated during compatible pollination. Based on these findings, a working model is proposed to explain how S-RNase and SLF interact with each other to make “a life or death” decision to control SI signalling response.