A Stigma-Specific Phospholipase D1 Is Required for Successful Pollination and Is Targeted by the Self-Incompatibility Response in Brassica napus

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dc.contributor.advisorSamuel, Marcus
dc.contributor.authorScandola, Sabine
dc.contributor.committeememberRo, Dae-Kyun
dc.contributor.committeememberMuench, Douglas
dc.contributor.committeememberHeyne, Belinda
dc.contributor.committeememberStone, Sophia
dc.date2018-03
dc.date.accessioned2018-01-22T16:55:17Z
dc.date.available2018-01-22T16:55:17Z
dc.date.issued2018-01-11
dc.description.abstractSelf-incompatibility (SI) is a genetic mechanism in hermaphroditic flowers that prevents inbreeding by rejection of self-pollen, while allowing cross or genetically diverse pollen to germinate on the stigma to successfully fertilize the ovules. In the Brassicaceae, this process is triggered by activation of a receptor kinase in the papillary cells of the stigma following binding of a haplotype-specific ligand produced by the pollen. Once activated, this phospho-relay converges on intracellular compatibility factors, which are immediately targeted for degradation by the E3 ligase, ARC1, resulting in the pollen rejection response. Through a proteomics approach using self-pollinated stigmatic proteins from canola (Brassica napus) phospholipase D1 (PLD1) was identified as one of the candidate proteins that is targeted for degradation following SI. In this study, I provide strong evidence for role of PLD1 as a stigmatic compatibility factor and a target of SI. Loss of PLD1 led to a reduction in pollen attachment and pollen tube penetration following compatible pollination, while overexpression of PLD1 in self-incompatible stigmas led to breakdown of SI response. PLD1 overexpression was also associated with enhanced membrane activity following SI pollination, and mimicked a compatible pollination. PLD1 can be ubiquitinated by ARC1 (ARM repeat-containing protein 1) and accumulated in ARC1-suppressed lines confirming PLD1 as direct target of ARC1 during SI response. I further showed that addition of phosphatidic acid (PA) to the PLD1 deficient stigmas could rescue compatibility and also improve self-pollen attachment on SI stigmas, establishing the essential nature of PA for a compatible interaction. I propose that PA produced by PLD1 activity during compatible pollination promotes vesicle fusion at the membrane to facilitate exocytosis necessary for pollen germination to occur, while SI response could abrogate this process by targeting PLD1 for degradation. Identification of PLD1 as a membrane modeling factor that is directly regulated by both compatible and incompatible pollination has significantly expanded our understanding of the complex mechanisms that operate during pollen-pistil interactions. Keywords: Canola, Phospholipase D1, Plant reproduction, Pollination, Proteasome, Self-Incompatibility, Phosphatidic aciden_US
dc.identifier.citationScandola, S. (2018). A Stigma-Specific Phospholipase D1 Is Required for Successful Pollination and Is Targeted by the Self-Incompatibility Response in Brassica napus (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/5380
dc.identifier.urihttp://hdl.handle.net/1880/106299
dc.language.isoenen_US
dc.publisher.facultyScienceen_US
dc.publisher.institutionUniversity of Calgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.en_US
dc.subjectPhospholipase D1en_US
dc.subjectCanolaen_US
dc.subjectPlant reproductionen_US
dc.subjectPollinationen_US
dc.subjectProteasomeen_US
dc.subjectSelf-Incompatibilityen_US
dc.subjectPhosphatidic aciden_US
dc.subject.classificationBiologyen_US
dc.subject.classificationBotanyen_US
dc.subject.classificationPlant Physiologyen_US
dc.subject.classificationPsychology--Developmentalen_US
dc.titleA Stigma-Specific Phospholipase D1 Is Required for Successful Pollination and Is Targeted by the Self-Incompatibility Response in Brassica napusen_US
dc.typedoctoral thesisen_US
thesis.degree.disciplineBiological Sciencesen_US
thesis.degree.grantorUniversity of Calgaryen_US
thesis.degree.nameDoctor of Philosophy (PhD)en_US
ucalgary.item.requestcopytrue
ucalgary.thesis.checklistI confirm that I have submitted all of the required forms to Faculty of Graduate Studies.en_US
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