Phase separation of S-RNase promotes self-incompatibility in Petunia hybrida  

作　　者：Huayang Tian Hongkui Zhang Huaqiu Huang Yu'e Zhang Yongbiao Xue 

机构地区：[1]The State Key Laboratory of Plant Cell and Chromosome Engineering,Institute of Genetics and Developmental Biology,the Chinese Academy of Sciences,Beijing 100101,China [2]University of the Chinese Academy of Sciences,Beijing 100049,China [3]Beiing Institute of Genomics,Chinese Academy of Sciences,National Center for Bioinformation,Beijing 100101,China

出　　处：《Journal of Integrative Plant Biology》2024年第5期986-1006,共21页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(32030007);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB27010302).

摘　　要：Self-incompatibility(SI)is an intraspecific reproductive barrier widely present in angiosperms.The SI system with the broadest occurrence in angiosperms is based on an S-RNase linked to a cluster of multiple S-locus F-box(SLF)genes found in the Solanaceae,Plantaginaceae,Rosaceae,and Rutaceae.Recent studies reveal that non-self S-RNase is degraded by the Skip Cullin F-box(SCF)SLF-mediated ubiquitin–proteasome system in a collaborative manner in Petunia,but how self-RNase functions largely remains mysterious.Here,we show that S-RNases form S-RNase condensates(SRCs)in the self-pollen tube cytoplasm through phase separation and the disruption of SRC formation breaks SI in self-incompatible Petunia hybrida.We further find that the pistil SI factors of a small asparagine-rich protein HT-B and thioredoxin h together with a reduced state of the pollen tube all promote the expansion of SRCs,which then sequester several actin-binding proteins,including the actin polymerization factor PhABRACL,the actin polymerization activity of which is reduced by S-RNase in vitro.Meanwhile,we find that S-RNase variants lacking condensation ability fail to recruit PhABRACL and are unable to induce actin foci formation required for pollen tube growth inhibition.Taken together,our results demonstrate that phase separation of S-RNase promotes SI response in P.hybrida,revealing a new mode of S-RNase action.

关 键 词：SELF-INCOMPATIBILITY S-RNASE phase separation 

分 类 号：S681.9[农业科学—观赏园艺]