title: Low temperature inhibits pollen tube growth by disruption of both tip-localized reactive oxygen species and endocytosis in Pyrus bretschneideri Rehd.
abstract: Low temperature (LT) negatively affects fertilization processes of flowering plants. Pollen tube growth is generally inhibited under LT stress; however, the mechanism(s) underlying this inhibition remain(s) largely unknown. Pollen tubes are tip-growing and the presence of tip-localized reactive oxygen species (ROS) is necessary for cellular functioning. Disruption of tip-localized ROS was observed in pear pollen tubes in vitro under low temperature of 4 °C (LT4). Diphenylene iodonium chloride, an NADPH oxidase (NOX) inhibitor, suppressed hydrogen peroxide formation in the cell walls of the subapical region in pear pollen tubes. Under LT4 stress, ROS disruption in pear pollen tubes mainly resulted from decreased NOX activity in the plasma membrane, indicating that NOX was the main source of ROS in this process. Moreover, LT4 remarkably decreased mitochondrial oxygen consumption and intracellular ATP production. The endocytosis, an energy-dependent process, disruption in pear pollen tubes under LT4 may be mediated by mitochondrial metabolic dysfunctions. Our data showed ROS and endocytosis events in pear pollen tubes responding to LT4 stress.
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Yong-Bin
authors: YB
authors: Gao
authors: Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiya, Aoba-ku, Sendai 981-8555, Japan.
authors: Chun-Lei
authors: CL
authors: Wang
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Ju-You
authors: JY
authors: Wu
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Hong-Sheng
authors: HS
authors: Zhou
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Xue-Ting
authors: XT
authors: Jiang
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Jun
authors: J
authors: Wu
authors: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: slzhang@njau.edu.cn.
authors: Shao-Ling
authors: SL
authors: Zhang
mesh_terms: D003080:Cold Temperature; D004705:Endocytosis; D006861:Hydrogen Peroxide / Q000378:metabolism; D017997:Leukotriene C4 / Q000037:antagonists & inhibitors*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D053205:Pollen Tube / Q000254:growth & development*; D031989:Pyrus / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D017997:Leukotriene C4; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase
keywords: 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide; DPI; Endocytosis; FM4-64; LT; LT4; Low temperature; Mitochondria; Mn-5,10,15,20-tetrakis(1-methyl-4-pyridyl) 21H,23H-porphin; N-(3-Triethylammoniumpropyl)-4-(6-(4-(Diethylamino) Phenyl) Hexatrienyl) Pyridinium Dibromide; NADPH oxidase; NBT; NOX; Nitroblue tetrazolium; PM; Pyrus bretschneideri Rehd.; ROS; Reactive oxygen species; TMPP; XTT; diphenylene iodonium chloride; low temperature; low temperature of 4 °C; plasma membrane; reactive oxygen species