Yu Guang-Hui, Zou Jie, Feng Jing, Peng Xiong-Bo, Wu Ju-You, Wu Ying-Liang, Palanivelu Ravishankar, Sun Meng-Xiang
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.
Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant hybrid rice, Wuhan University, Wuhan 30072, China.
J Exp Bot. 2014 Jul;65(12):3235-48. doi: 10.1093/jxb/eru171. Epub 2014 May 5.
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.
γ-氨基丁酸（GABA）与花粉管生长有关，但其介导的分子和细胞机制尚不清楚。本文表明，外源GABA可调节烟草花粉粒和花粉管质膜上的假定Ca(2+)渗透通道。全细胞电压钳实验和非侵入性微测量技术（NMT）显示，外源GABA作用下花粉管中Ca(2+)内流增加。研究还表明，GABA生物合成的限速酶谷氨酸脱羧酶（GAD）参与Ca(2+)渗透通道的反馈控制，以波动细胞内GABA水平，从而调节花粉管生长。这些发现表明，与Ca(2+)渗透通道相关的GAD活性传递细胞外GABA信号，并整合多个信号通路以调节烟草花粉管生长。因此，这些数据解释了GABA如何介导花柱与生长中的花粉管之间的通讯。
