New opportunities and insights into Papaver selfincompatibility by imaging engineered Arabidopsis pollen

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Type Article
Original languageEnglish
Article numbereraa092
JournalJournal of Experimental Botany
Early online date26 Feb 2020
Publication statusE-pub ahead of print - 26 Feb 2020
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Pollen tube growth is essential for plant reproduction. Their rapid extension using polarized tip growth provides an exciting system for studying this specialized type of growth. Self-Incompatibility (SI) is a genetically controlled mechanism to prevent self-fertilisation. Mechanistically, one of the best-studied SI systems is that of Papaver rhoeas (poppy). This utilizes two S-determinants: stigma-expressed PrsS and pollen-expressed PrpS. Interaction of cognate PrpS-PrsS triggers a signalling network, causing rapid growth arrest and programmed cell death (PCD) in incompatible pollen. We previously demonstrated that transgenic Arabidopsis thaliana pollen expressing PrpS-GFP can respond to Papaver PrsS with remarkably similar responses to those observed in incompatible Papaver pollen. Here we describe recent advances using these transgenic plants combined with genetically encoded fluorescent probes to monitor SI-induced cellular alterations including: cytosolic calcium, pH, the actin cytoskeleton, clathrin-mediated endocytosis (CME) and the vacuole. This approach has allowed us to study the SI response in depth, using multi-parameter live-cell imaging approaches that were not possible in Papaver. This lays the foundations for new opportunities to elucidate key mechanisms involved in SI. Here we establish that clathrin-mediated endocytosis is disrupted in self-incompatible pollen. Moreover, we reveal new detailed information about F-actin remodelling in pollen tubes after SI.