title: OsABCG15 encodes a membrane protein that plays an important role in anther cuticle and pollen exine formation in rice.
abstract: An ABC transporter gene ( OsABCG15 ) was proven to be involved in pollen development in rice. The corresponding protein was localized on the plasma membrane using subcellular localization. Wax, cutin, and sporopollenin are important for normal development of the anther cuticle and pollen exine, respectively. Their lipid soluble precursors, which are produced in the tapetum, are then secreted and transferred to the anther and microspore surface for polymerization. However, little is known about the mechanisms underlying the transport of these precursors. Here, we identified and characterized a member of the G subfamily of ATP-binding cassette (ABC) transporters, OsABCG15, which is required for the secretion of these lipid-soluble precursors in rice. Using map-based cloning, we found a spontaneous A-to-C transition in the fourth exon of OsABCG15 that caused an amino acid substitution of Thr-to-Pro in the predicted ATP-binding domain of the protein sequence. This osabcg15 mutant failed to produce any viable pollen and was completely male sterile. Histological analysis indicated that osabcg15 exhibited an undeveloped anther cuticle, enlarged middle layer, abnormal Ubisch body development, tapetum degeneration with a falling apart style, and collapsed pollen grains without detectable exine. OsABCG15 was expressed preferentially in the tapetum, and the fused GFP-OsABCG15 protein was localized to the plasma membrane. Our results suggested that OsABCG15 played an essential role in the formation of the rice anther cuticle and pollen exine. This role may include the secretion of the lipid precursors from the tapetum to facilitate the transfer of precursors to the surface of the anther epidermis as well as to microspores.
authors.affiliation: College of Agronomy and Biotechnology, Southwest University, Chongqing, 400715, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Wu
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Guan
authors.forename: Zigang
authors.initials: Z
authors.lastname: Wu
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.forename: Richard
authors.initials: R
authors.lastname: Converse
authors.forename: Yuanxin
authors.initials: Y
authors.lastname: Huang
authors.forename: Jinxiong
authors.initials: J
authors.lastname: Mao
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Wang
authors.forename: Hengqi
authors.initials: H
authors.lastname: Min
authors.forename: Dongyang
authors.initials: D
authors.lastname: Kan
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D002462:Cell Membrane / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D035264:Flowers / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D018528:ATP-Binding Cassette Transporters; D008565:Membrane Proteins; D010940:Plant Proteins; D049452:Green Fluorescent Proteins