Overexpression of a Mitogen-Activated Protein Kinase SlMAPK3 Positively Regulates Tomato Tolerance to Cadmium and Drought Stress.
Mitogen-activated protein kinases (MAPKs) activation is a common defense response of plants to a range of abiotic stressors. SlMPK3, a serine-threonine protein kinase, has been reported as an important member of protein kinase cascade that also functions on plant stress tolerance. In this study, we cloned SlMPK3 from tomato and studied its role in cadmium (Cd2+) and drought tolerance. The results showed that transcripts of SlMAPK3 differentially accumulated in various plant tissues and were remarkably induced by different abiotic stressors and exogenous hormone treatments. Overexpression of SlMAPK3 increased tolerance to Cd2+ and drought as reflected by an increased germination rate and improved seedling growth. Furthermore, transgenic plants overexpressing SlMAPK3 showed an increased leaf chlorophyll content, root biomass accumulation and root activity under Cd2+ stress. Chlorophyll fluorescence analysis revealed that transgenic plants demonstrated an increased photosynthetic activity as well as contents of chlorophyll, proline, and sugar under drought stress. Notably, cadmium- and drought-induced oxidative stress was substantially attenuated in SlMAPK3 overexpressing plants as evidenced by lower malondialdehyde and hydrogen peroxide accumulation, and increased activity and transcript abundance of enzymatic antioxidants under stress conditions compared to that of wild-type. Our findings provide solid evidence that overexpression of SlMAPK3 gene in tomato positively regulates tolerance to Cd2+ and drought stress, which may have strengthen the molecular understanding of SlMAPK3 gene to improve abiotic stress tolerance.
['Muhammad|Tayeb|T|', 'Zhang|Jie|J|', 'Ma|Yalin|Y|', 'Li|Yushun|Y|', 'Zhang|Fei|F|', 'Zhang|Yan|Y|', 'Liang|Yan|Y|']
D000222:Adaptation, Physiological D002104:Cadmium D055864:Droughts D018506:Gene Expression Regulation, Plant D006861:Hydrogen Peroxide D018551:Lycopersicon esculentum D020928:Mitogen-Activated Protein Kinases D018384:Oxidative Stress D010641:Phenotype D010788:Photosynthesis D063245:Plant Development D010940:Plant Proteins D030821:Plants, Genetically Modified D017382:Reactive Oxygen Species D013312:Stress, Physiological
SlMAPK3 tomato cadmium drought antioxidant enzymes lipid peroxidation reactive oxygen species