title: The microtubule cytoskeleton and pollen tube Golgi vesicle system are required for in vitro S-RNase internalization and gametic self-incompatibility in apple.
abstract: S-RNase is the female determinant of gametophytic self-incompatibility in apple and is usually considered to be the reason for rejection of pollen. In this study, we investigated the role of microtubules (MTs) in internalization of S-RNases by pollen tubes cultured in vitro. The results showed that S-RNase was imported into the pollen tube where it inhibits pollen tube growth, and that S-RNase is co-localized with the Golgi vesicle during the internalization process. Moreover, MT depolymerization is observed following accumulation of S-RNases in the pollen cytosol. On the other hand, S-RNase was prevented from entering the pollen tube when the pollen was treated with the actin filament (AF) inhibitor latrunculin A (LatA), the MT inhibitor oryzalin, or the MT stabilizer taxol at subtoxic concentrations. These hindered the construction of the MT, with pollen tubes capable of growth under these conditions. Pollen tubes showed improved growth in self-pollinated styles that were pre-treated with taxol. This suggests that cytoskeleton antagonists can prevent S-RNase-mediated inhibition of pollen tubes in vivo by blocking S-RNase internalization. These results suggest that an intact and dynamic cytoskeleton is required for the in vitro internalization of S-RNase, as shown by the effects of various cytoskeleton inhibitors. S-RNase internalization takes place via a membrane/cytoskeleton-based Golgi vesicle system, which can also affect self-incompatibility in apple.
authors: Laboratory of Fruit Cell and Molecular Breeding, College of Agronomy and Bio-tech, China Agricultural University, Beijing 100193, China.
authors: Dong
authors: D
authors: Meng
authors: Zhaoyu
authors: Z
authors: Gu
authors: Hui
authors: H
authors: Yuan
authors: Aide
authors: A
authors: Wang
authors: Wei
authors: W
authors: Li
authors: Qing
authors: Q
authors: Yang
authors: Yuandi
authors: Y
authors: Zhu
authors: Tianzhong
authors: T
authors: Li
mesh_terms: D015153:Blotting, Western; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D022162:Cytoplasmic Vesicles / Q000378:metabolism*; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004136:Dinitrobenzenes / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D006056:Golgi Apparatus / Q000378:metabolism*; D027845:Malus / Q000166:cytology / Q000378:metabolism*; D018613:Microscopy, Confocal; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D011058:Pollen / Q000166:cytology / Q000378:metabolism; D053205:Pollen Tube / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D060436:Self-Incompatibility in Flowering Plants; D013424:Sulfanilamides / Q000494:pharmacology; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004136:Dinitrobenzenes; D013424:Sulfanilamides; D053778:Thiazolidines; C012465:oryzalin; D012260:Ribonucleases; C022542:ribonuclease S; D017239:Paclitaxel; C037067:latrunculin A
keywords: Apple; Cytoskeleton; Depolymerization; Golgi vesicle; S-RNase; Self-incompatibility