RESUMO

The stress phytohormone abscisic acid (ABA) plays pivotal roles in plants' adaptive responses to adverse environments. Molybdenum cofactor sulfurases influence aldehyde oxidase activity and ABA biosynthesis. In this study, we isolated a novel EsMcsu1 gene encoding a molybdenum cofactor sulfurase from Eutrema salsugineum. EsMcus1 transcriptional patterns varied between organs, and its expression was significantly upregulated by abiotic stress or ABA treatment. Alfalfa plants that overexpressed EsMcsu1 had a higher ABA content than wild-type (WT) plants under drought stress conditions. Furthermore, levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde were lower in the transgenic plants than in the WT plants after drought treatment, suggesting that the transgenic plants experienced less ROS-mediated damage. However, the expression of several stress-responsive genes, antioxidant enzyme activity, and osmolyte (proline and total soluble sugar) levels in the transgenic plants were higher than those in the WT plants after drought treatment. Therefore, EsMcsu1 overexpression improved drought tolerance in alfalfa plants by activating a series of ABA-mediated stress responses.

Assuntos

Ácido Abscísico/biossíntese , Adaptação Biológica , Brassicaceae/genética , Secas , Expressão Gênica , Medicago sativa/genética , Medicago sativa/metabolismo , Proteínas de Plantas/genética , Adaptação Biológica/genética , Sequência de Aminoácidos , Antioxidantes/metabolismo , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Concentração Osmolar , Oxirredução , Fenótipo , Filogenia , Reguladores de Crescimento de Plantas/biossíntese , Proteínas de Plantas/química , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Estresse Fisiológico/genética