Research Associate The Chinese Univrsity of Hong Kong Shatin, Hong Kong
Body of Abstract: Guanine nucleotide-binding proteins (G-proteins) have been known as signalling molecules that regulate stress responses in plants. G-proteins can be positive or negative regulators of stresses including drought, salinity, and pathogen infection. Recently, the activators of G-proteins were reported to be regulating ABA signalling. ABA is an important stress hormone mediating both abiotic and biotic stress responses. The correlation between G-protein activators and ABA signalling provides a new perspective of studying ABA signalling. However, the components of such a signalling cascade remains largely unknown. In this study, we obtained a G-protein knockdown Arabidopsis mutant. By seed germination and stomatal aperture assays, we found that the G-protein knockdown mutant was more sensitive to ABA compared to the wild type. Under ABA treatment, expression analyses showed that stress-responsive genes had lower expression levels in the G-protein knockdown mutant compared to the wild type. The experimental data suggest that the G-protein mediates stress responses via regulating ABA sensitivity. This study supplements previous studies on the G-protein activator – ABA signalling cascade and provides new insights of the functions of G-proteins.