title: Tapetal oleosins play an essential role in tapetosome formation and protein relocation to the pollen coat.
abstract: The Arabidopsis pollen grain is covered by a lipidic pollen coat representing select constituents released upon the programmed cell death of the anther secretory tapetum. These constituents originate primarily from two specialized tapetal organelles, elaioplasts and tapetosomes. Tapetosomes are distinctive Brassicaceae organelles derived from the endoplasmic reticulum that store triacylglycerols, flavonoids, alkanes, and proteins. The tapetosome triacylglycerols are found within lipid droplets surrounded by the highly variable tapetal oleosins that eventually generate the most abundant proteins of the pollen coat. Many questions remain regarding the sub-cellular targeting of tapetal oleosins as well as their role in tapetosome formation. Translational fusions of different tapetal oleosins or their derived domains to marker proteins were introduced into Arabidopsis thaliana to investigate their localization, processing and function. Arabidopsis tapetal oleosins were shown to be proteolytically cleaved following tapetum degeneration and different protein domains were targeted to the pollen coat despite vast differences in composition and size. Importantly, specific fusions were discovered to affect distinct aspects of tapetosome formation. This report not only highlighted the critical role of individual tapetal oleosin domains in Arabidopsis tapetosome formation, but revealed translational fusions to be a valuable tool in deciphering this evidently complex developmental process.
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: Madeleine
authors: M
authors: Lévesque-Lemay
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: Denise
authors: D
authors: Chabot
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: Keith
authors: K
authors: Hubbard
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: John K
authors: JK
authors: Chan
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: Shea
authors: S
authors: Miller
authors: Agriculture and AgriFood Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
authors: Laurian S
authors: LS
authors: Robert
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D029688:Brassica napus / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D015388:Organelles / Q000737:chemistry / Q000378:metabolism; D059828:Plant Cells / Q000737:chemistry / Q000378:metabolism; D030821:Plants, Genetically Modified; D011058:Pollen / Q000737:chemistry / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D008055:Lipids; D011993:Recombinant Fusion Proteins; C079353:oleosin protein, Arabidopsis; C081483:tryphine; D049452:Green Fluorescent Proteins
keywords: Arabidopsis; Brassica; GFP; GUS; oleosin; tapetum