关键词: 非生物胁迫；生物胁迫；转基因棉花；转录因子；大丽轮枝菌

Abstract:

AP2/ERF transcription factors widely exist in plants, and participate in various biotic and abiotic stress responses. In order to improve cotton resistance to disease and abiotic stress, the expression vector containing HhERF2 and PeDREB2a transcription factor genes, which were isolated from resistant excellent psammophyte Halimodendron halodendron and Populus euphratica respectively, and driven by rd29A promoter, was constructed and transferred into cotton (Gossypium hirsutum) by pollen-tube pathway transformation technology. After the transgenic cottons were treated with stress, the ectopic expression HhERF2 and PeDREB2a genes, and some downstream relative pathogenesis-related (PR) genes were analyzed   by Real-time PCR in transgenic cotton. The results showed that the expression of HhERF2 gene could be induced by Verticillium dahliae (Vd), drought and salt, while PeDREB2a could only be induced by drought and salt. Inoculated by Vd, the expression of some downstream relative PR genes and the enzyme activity that related to phenolic metabolism such as: PAL, SOD and POD all increased in the transgenic lines at the same times. The resistance to Vd was also enhanced in transgenic cotton. Analysis of physiological and biochemical characteristics under drought and high-salt stresses, which indicated that compared with the contrast, the soluble carbohydrates and relative water concentration in the leaves of transgenic cotton were significantly elevated, while the conductivity and malondialdehyde (MDA) content decreased significantly. These results demonstrated that transgenic cotton performed excellent tolerability to Vd, drought and high-salt stresses.

Key words: abiotic stress, biotic stress, transgenic cotton, transcription factor, Verticillium dahliae