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 Ca2+- permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and noninvasive micromeasurement technology (NMT) revealed that the influx of Ca2+ 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 Ca2+-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca2+-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.
Original language | English (US) |
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Pages (from-to) | 3235-3248 |
Number of pages | 14 |
Journal | Journal of Experimental Botany |
Volume | 65 |
Issue number | 12 |
DOIs | |
State | Published - Jul 2014 |
Keywords
- Cell-cell communication
- Glutamate decarboxylase
- Nicotiana tabacum
- Pollen tube
- γ-aminobutyric acid
ASJC Scopus subject areas
- Physiology
- Plant Science