title: Apple MdABCF assists in the transportation of S-RNase into pollen tubes.
abstract: Self-incompatibility (SI) is a reproductive isolation mechanism in flowering plants. Plants in the Solanaceae, Rosaceae and Plantaginaceae belong to the gametophytic self-incompatibility type. S-RNase, which is encoded by a female-specific gene located at the S locus, degrades RNA in the pollen tube and causes SI. Recent studies have provided evidence that S-RNase is transported non-selectively into the pollen tube, but have not specified how this transportation is accomplished. We show here that the apple (Malus domestica) MdABCF protein, which belongs to group F of the ABC transporter family, assists in transportation of S-RNase into the pollen tube. MdABCF is located in the pollen tube membrane and interacts with S-RNase. S-RNase was unable to enter the pollen tube when MdABCF was silenced by antisense oligonucleotide transfection. Our results show that MdABCF assists in transportation of either self or non-self S-RNase into the pollen tube. Moreover, MdABCF coordinates with the cytoskeleton to transport S-RNase. Blockage of S-RNase transport disrupts self-incompatibility in this system.
authors.affiliation: Laboratory of Fruit Cell and Molecular Breeding, College of Agronomy and Bio-Tech, China Agricultural University, Beijing, 100193, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Meng
authors.forename: Zhaoyu
authors.initials: Z
authors.lastname: Gu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Aide
authors.initials: A
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Yuan
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.forename: Tianzhong
authors.initials: T
authors.lastname: Li
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D027845:Malus / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D053205:Pollen Tube / Q000378:metabolism*; D021381:Protein Transport; D060047:Reproductive Isolation; D012260:Ribonucleases / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D010940:Plant Proteins; D012260:Ribonucleases
keywords: MdABCF; S-RNase; apple; pollen tube; self-incompatibility; transportation