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J Exp Bot. 2014 Jul;65(12):3235-48. doi: 10.1093/jxb/eru171. Epub 2014 May 5.

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.

Author information

1
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.
2
Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China.
3
State key laboratory of Virology, College of Life Science, Wuhan University, Wuhan 430072, China.
4
College of Horticulture, State key laboratory of crop genetics and germplasm enhancement, Nanjing Agriculture University, Nanjing 210095, China.
5
School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA.
6
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.

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.

KEYWORDS:

Ca2+-permeable channel; Nicotiana tabacum; cell–cell communication; glutamate decarboxylase; pollen tube.; γ-Aminobutyric acid

PMID:
24799560
PMCID:
PMC4071839
DOI:
10.1093/jxb/eru171
[Indexed for MEDLINE]
Free PMC Article

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