ABI2-dependent abscisic acid signalling controls HrpN-induced drought tolerance in Arabidopsis

• Published in: Planta 2005-06, Vol.221 (3), p.313-327
• Main Authors: Dong, H.P, Yu, H, Bao, Z, Guo, X, Peng, J, Yao, Z, Chen, G, Qu, S, Dong, H
• Format: Article
• Language: English
• Subjects: Abscisic acid; Abscisic Acid - metabolism; Adaptation, Biological - drug effects; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Bacterial Outer Membrane Proteins - pharmacology; bacterial proteins; Biological and medical sciences; Cell membranes; Cell physiology; Dehydration; disease resistance; Drought; Drought resistance; drought tolerance; Erwinia amylovora; Flowers & plants; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Plant - drug effects; Genes; Leaves; Molecular and cellular biology; molecular sequence data; Mutation; nucleotide sequences; Pathogens; Phenotype; phenotypic variation; phosphoprotein phosphatase; Phosphoprotein Phosphatases - genetics; Phosphoprotein Phosphatases - metabolism; physiological response; Plant cells; Plant growth; plant morphology; plant pathogenic bacteria; plant physiology; plant response; plant stress; Plants; Pseudomonas syringae; Pseudomonas syringae pv. tomato; Signal transduction; Signal Transduction - drug effects; Stomata; stomatal movement; Transpiration; Water stress
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-004-1444-x

HrpN, a protein produced by the plant pathogenic bacterium Erwinia amylovora, has been shown to stimulate plant growth and resistance to pathogens and insects. Here we report that HrpN activates abscisic acid (ABA) signalling to induce drought tolerance (DT) in Arabidopsis thaliana L. plants grown with water stress. Spraying wild-type plants with HrpN-promoted stomatal closure decreased leaf transpiration rate, increased moisture and proline levels in leaves, and alleviated extents of damage to cell membranes and plant drought symptoms caused by water deficiency. In plants treated with HrpN, ABA levels increased; expression of several ABA-signalling regulatory genes and the important effector gene rd29B was induced or enhanced. Induced expression of rd29B, promotion of stomatal closure, and reduction in drought severity were observed in the abi1-1 mutant, which has a defect in the phosphatase ABI1, after HrpN was applied. In contrast, HrpN failed to induce these responses in the abi2-1 mutant, which is impaired in the phosphatase ABI2. Inhibiting wild-type plants to synthesize ABA eliminated the role of HrpN in promoting stomatal closure and reducing drought severity. Moreover, resistance to Pseudomonas syringae developed in abi2-1 as in wild-type plants following treatment with HrpN. Thus, an ABI2-dependent ABA signalling pathway is responsible for the induction of DT but does not affect pathogen defence under the circumstances of this study.