Abstract:

To explore the mechanism of γ- aminobutyric acid (GABA) on plant flowering, different concentration of exogenous GABA (1, 5, 10 mmol/L) was sprayed on Arabidopsis 7 days seedlings at 1 day interval, the mock was spraying with clear water. This treatment was continuous to 4 weeks. The results showed that, GABA at different extent could promote early flowering in Arabidopsis grown both in long-day (16 h light/8 h dark cycle) and short-day (8 h light/16 h dark cycle) conditions. Quantitative RT-PCR technique was employed to investigate the expression level of flowering inhibitor gene FLC, autonomous flowering pathway gene FCA (FLOWERING TIME CONTROL PROTEIN FCA) and inflorescence meristem identification gene LEAFY (LFY). The results indicated that, GABA treatment could down regulate the expression level Flowering Locusc C (FLC) 2-5 folds, whereas the expression level of FCA and LFY was enhanced 1.5-6 times and 3-11 folds, respectively. The preliminary results indicated that, the role of GABA on Arabidopsis flowering acceleration was probably via the autonomous-pathway in which GABA signals triggered the up-regulation of FCA, down-regulation expression of FLC and thereby promoted the expression level of LFY and at last achieved early flowering regulation in plants.