title: Exogenous γ-aminobutyric acid (GABA) affects pollen tube growth via modulating putative Ca2+-permeable membrane channels and is coupled to negative regulation on glutamate decarboxylase.
abstract: γ-Aminobutyric acid (GABA) is implicated in pollen tube growth, but the molecular and cellular mechanisms that it mediates are largely unknown. Here, it is shown that exogenous GABA modulates putative Ca(2+)-permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and non-invasive micromeasurement technology (NMT) revealed that the influx of Ca(2+) increases in pollen tubes in response to exogenous GABA. It is also demonstrated that glutamate decarboxylase (GAD), the rate-limiting enzyme of GABA biosynthesis, is involved in feedback controls of Ca(2+)-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca(2+)-permeable channels relays an extracellular GABA signal and integrates multiple signal pathways to modulate tobacco pollen tube growth. Thus, the data explain how GABA mediates the communication between the style and the growing pollen tubes.
authors.affiliation: Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China Key Laboratory for Biotechnology of the State Ethnic Affairs Commission, Hubei provincial Key laboratory for protection and application of special plants in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China.
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Yu
authors.affiliation: Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zou
authors.affiliation: State key laboratory of Virology, College of Life Science, Wuhan University, Wuhan 430072, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China.
authors.forename: Xiong-Bo
authors.initials: XB
authors.lastname: Peng
authors.affiliation: College of Horticulture, State key laboratory of crop genetics and germplasm enhancement, Nanjing Agriculture University, Nanjing 210095, China.
authors.forename: Ju-You
authors.initials: JY
authors.lastname: Wu
authors.affiliation: State key laboratory of Virology, College of Life Science, Wuhan University, Wuhan 430072, China.
authors.forename: Ying-Liang
authors.initials: YL
authors.lastname: Wu
authors.affiliation: School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA.
authors.forename: Ravishankar
authors.initials: R
authors.lastname: Palanivelu
authors.affiliation: Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China mxsun@whu.edu.cn.
authors.forename: Meng-Xiang
authors.initials: MX
authors.lastname: Sun
mesh_terms: D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000378:metabolism; D053205:Pollen Tube / Q000254:growth & development / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000235:genetics* / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D002147:Calmodulin; D010940:Plant Proteins; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase
keywords: Ca2+-permeable channel; Nicotiana tabacum; cell–cell communication; glutamate decarboxylase; pollen tube.; γ-Aminobutyric acid