title: Proteomic analysis of Brassica stigmatic proteins following the self-incompatibility reaction reveals a role for microtubule dynamics during pollen responses.
abstract: Mate selection and maintenance of genetic diversity is crucial to successful reproduction and species survival. Plants utilize self-incompatibility system as a genetic barrier to prevent self pollen from developing on the pistil, leading to hybrid vigor and diversity. In Brassica (canola, kale, and broccoli), an allele-specific interaction between the pollen SCR/SP11 (S-locus cysteine rich protein/S locus protein 11) and the pistil S Receptor Kinase, results in the activation of SRK which recruits the Arm Repeat Containing 1 (ARC1) E3 ligase to the proteasome. The targets of Arm Repeat Containing 1 are proposed to be compatibility factors, which when targeted for degradation by Arm Repeat Containing 1 results in pollen rejection. Despite the fact that protein degradation is predicted to be important for successful self-pollen rejection, the identity of the various proteins whose abundance is altered by the SI pathway has remained unknown. To identify potential candidate proteins regulated by the SI response, we have used the two-dimensional difference gel electrophoresis analysis, coupled with matrix-assisted laser desorption ionization/time of flight/MS. We identified 56 differential protein spots with 19 unique candidate proteins whose abundance is down-regulated following self-incompatible pollinations. The identified differentials are predicted to function in various pathways including biosynthetic pathways, signaling, cytoskeletal organization, and exocytosis. From the 19 unique proteins identified, we investigated the role of tubulin and the microtubule network during both self-incompatible and compatible pollen responses. Moderate changes in the microtubule network were observed with self-incompatible pollinations; however, a more distinct localized break-down of the microtubule network was observed during compatible pollinations, that is likely mediated by EXO70A1, leading to successful pollination.
authors: University of Calgary, Department of Biological Sciences, Calgary, Canada. msamuel@ucalgary.ca
authors: Marcus A
authors: MA
authors: Samuel
authors: Wenqiang
authors: W
authors: Tang
authors: Muhammad
authors: M
authors: Jamshed
authors: Julian
authors: J
authors: Northey
authors: Darshan
authors: D
authors: Patel
authors: Daryl
authors: D
authors: Smith
authors: K W Michael
authors: KW
authors: Siu
authors: Douglas G
authors: DG
authors: Muench
authors: Zhi-Yong
authors: ZY
authors: Wang
authors: Daphne R
authors: DR
authors: Goring
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D019607:Brassicaceae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015536:Down-Regulation; D035264:Flowers / Q000378:metabolism / Q000502:physiology; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D008970:Molecular Weight; D017239:Paclitaxel / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000378:metabolism / Q000502:physiology*; D054817:Pollination; D055550:Protein Stability; D040901:Proteomics; D060436:Self-Incompatibility in Flowering Plants; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology; D057825:Two-Dimensional Difference Gel Electrophoresis; D054875:Ubiquitination
chemical_list: D029681:Arabidopsis Proteins; C515561:EXO70A1 protein, Arabidopsis; C429183:MOR1 protein, Arabidopsis; D008869:Microtubule-Associated Proteins; D010940:Plant Proteins; D050257:Tubulin Modulators; D017239:Paclitaxel