title: Actin depolymerization is sufficient to induce programmed cell death in self-incompatible pollen.
abstract: Self-incompatibility (SI) prevents inbreeding through specific recognition and rejection of incompatible pollen. In incompatible Papaver rhoeas pollen, SI triggers a Ca2+ signaling cascade, resulting in the inhibition of tip growth, actin depolymerization, and programmed cell death (PCD). We investigated whether actin dynamics were implicated in regulating PCD. Using the actin-stabilizing and depolymerizing drugs jasplakinolide (Jasp) and latrunculin B, we demonstrate that changes in actin filament levels or dynamics play a functional role in initiating PCD in P. rhoeas pollen, triggering a caspase-3-like activity. Significantly, SI-induced PCD in incompatible pollen was alleviated by pretreatment with Jasp. This represents the first account of a specific causal link between actin polymerization status and initiation of PCD in a plant cell and significantly advances our understanding of the mechanisms involved in SI.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, England, UK.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Thomas
authors.forename: Shanjin
authors.initials: S
authors.lastname: Huang
authors.forename: Shutian
authors.initials: S
authors.lastname: Li
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Staiger
authors.forename: Vernonica E
authors.initials: VE
authors.lastname: Franklin-Tong
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D047630:Depsipeptides / Q000494:pharmacology; D010207:Papaver / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D011058:Pollen / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000199:Actins; D001704:Biopolymers; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D013844:Thiazoles; D053778:Thiazolidines; C057531:jasplakinolide; D053148:Caspase 3; D020169:Caspases; C037068:latrunculin B