title: Cullin1-P is an Essential Component of Non-Self Recognition System in Self-Incompatibility in Petunia.
abstract: Self-incompatibility (SI) in flowering plants is a genetic reproductive barrier to distinguish self- and non-self pollen to promote outbreeding. In Solanaceae, self-pollen is rejected by the ribonucleases expressed in the styles (S-RNases), via its cytotoxic function. On the other side, the male-determinant is the S-locus F-box proteins (SLFs) expressed in pollen. Multiple SLFs collaboratively detoxify non-self S-RNases, therefore, non-self recognition is the mode of self-/non-self discrimination in Solanaceae. It is considered that SLFs function as a substrate-recognition module of the Skp1-Cullin1-F-box (SCF) complex that inactivates non-self S-RNases via their polyubiquitination, which leads to degradation by 26S proteasome. In fact, PhSSK1 (Petunia hybrida SLF-interacting Skp1-like1) was identified as a specific component of SCFSLFand was shown to be essential for detoxification of S-RNase in Petunia However, different molecules are proposed as the candidate Cullin1, another component of SCFSLF, and there is as yet no definite conclusion. Here, we identified five Cullin1s from the expressed sequence tags (ESTs) derived from the male reproductive organ in Petunia Among them, only PhCUL1-P was co-immunoprecipitated with S7-SLF2. In vitro protein-binding assay suggested that PhSSK1 specifically forms a complex with PhCUL1-P in an SLF-dependent manner. Knockdown of PhCUL1-P suppressed fertility of transgenic pollen in cross-compatible pollination in the functional S-RNase-dependent manner. These results suggested that SCFSLFselectively uses PhCUL1-P. Phylogeny of Cullin1s indicates that CUL1-P is recruited into the SI machinery during the evolution of Solanaceae, suggesting that the SI components have evolved differently among species in Solanaceae and Rosaceae, despite both families sharing the S-RNase-based SI.
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
authors: Ken-Ichi
authors: KI
authors: Kubo
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
authors: Mai
authors: M
authors: Tsukahara
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
authors: Sota
authors: S
authors: Fujii
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
authors: Kohji
authors: K
authors: Murase
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
authors: Yuko
authors: Y
authors: Wada
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.|Present address: The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
authors: Tetsuyuki
authors: T
authors: Entani
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.|Present address: The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
authors: Megumi
authors: M
authors: Iwano
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan takayama@bs.naist.jp.
authors: Seiji
authors: S
authors: Takayama
mesh_terms: D044842:Cullin Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D035683:MicroRNAs / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D019683:Penetrance; D032306:Petunia / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000235:genetics; D054817:Pollination; D011485:Protein Binding; D012098:Reproduction; D012260:Ribonucleases / Q000378:metabolism; D027824:Rosaceae / Q000235:genetics; D060436:Self-Incompatibility in Flowering Plants / Q000235:genetics; D019076:Transgenes
chemical_list: D044842:Cullin Proteins; D035683:MicroRNAs; D010940:Plant Proteins; D012260:Ribonucleases; C022542:ribonuclease S
keywords: 
  Petunia hybrida
  ; Evolution of self-incompatibility; Non-self recognition; S-RNase-based self-incompatibility; Skp1-Cullin1-F-box type E3 ubiquitin ligase; Solanaceae