Find in Library

GTP is an important signaling molecule involved in the growth, development, and stress adaptability of plants. The functions are mediated via binding to GTPases which are in turn regulated by GTPase-activating proteins (GAPs). Satellite reports have suggested the positive roles of GAPs in regulating ABA signaling and pathogen resistance in plants. However, the molecular mechanisms that bring forth the pathogen resistance have remained unclear. In this study, we demonstrated that the expression of <i>AtGAP1</i> was inducible by <i>Pseudomonas syringae</i> pv. <i>tomato</i> DC3000 (<i>Pst</i> DC3000). The overexpression of <i>AtGAP1</i> in Arabidopsis promoted the expression of <i>PR1</i> and the resistance to <i>Pst</i> DC3000. Proteomic analyses revealed the enhanced accumulation of cell-wall-modifying proteins as a result of <i>AtGAP1</i> overexpression. By microscopic analyses, we showed that the overexpression of <i>AtGAP1</i> resulted in increased thickness of the mesophyll cell wall and reduced stomatal aperture, which are effective strategies for restricting the entry of foliar pathogens. Altogether, we demonstrated that AtGAP1 increases the resistance to <i>Pst</i> DC3000 in Arabidopsis by promoting cellular strategies that restrict the entry of pathogens into the cells. These results point to a future direction for studying the modes of action of GAPs in regulating plant cell structures and disease resistance.