title: 'A life or death decision' for pollen tubes in S-RNase-based self-incompatibility.
abstract: Mate choice is an essential process during sexual plant reproduction, in which self-incompatibility (SI) is widely adopted as an intraspecific reproductive barrier to inhibit self-fertilization by many flowering plants. Genetic studies show that a single polymorphic S-locus, encoding at least two components from both the pollen and pistil sides, controls the discrimination of self and non-self pollen. In the Solanaceae, Plantaginaceae, and Rosaceae, an S-RNase-based SI mechanism is involved in such a discrimination process. Recent studies have provided some important clues to how a decision is made to accept cross pollen or specifically to reject self pollen. In this review, the molecular features of the pistil and pollen S-specificity factors are briefly summarized and then our current knowledge of the molecular control of cross-pollen compatibility (CPC) and self-pollen incompatibility (SPI) responses, respectively, is presented. The possible biochemical mechanisms of the specificity determinant between the pistil and pollen S factors are discussed and a hypothetical S-RNase endosome sorting model is proposed to illustrate the distinct destinies of pollen tubes following compatible and incompatible pollination.
authors.affiliation: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences and National Center for Plant Gene Research, Beijing 100101, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Zhao
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Sui
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Yongbiao
authors.initials: Y
authors.lastname: Xue
mesh_terms: D000483:Alleles; D003433:Crosses, Genetic; D056426:Genetic Loci / Q000235:genetics*; D007178:Inbreeding; D053205:Pollen Tube / Q000201:enzymology*; D012260:Ribonucleases / Q000378:metabolism*
chemical_list: D012260:Ribonucleases