Abstract:

【Objective】 The transformation of BZR1, a BR signal transduction component to tomato and its effect on characters of fruit of tomato was investigated in present study. 【Method】 The bzr1 gene was introduced into tomato cultivar Zhongshusihao via tumefaciens-mediated transformation and confirmed by molecular test and genetic analysis. The content of main quality components and pigments, as well as ethylene evolution rate was analyzed in fruits of transgenic tomato line and non-transgenic line (control) at four typical developmental stages. The expression of BR biosynthetic and regulated genes, as well as ethylene biosynthetic, response, and receptor genes was also analyzed. 【Result】 Significantly higher contents of soluble solids, organic acid, soluble proteins, vitamin C, lycopene and total carotenold, as well as the ethylene evolution rate in fruit of turning stage were observed in transgenic tomato line compared with the control. The expression of BR regulated gene LeBR1 was higher in transgenic line than in the control at the stage of seedling and early three developmental stages of fruit. The expression of LeACS4 gene encoding ACC synthase, which catalyzes the rate-limiting step of ethylene biosynthesis, was higher in the fruit of transgenic line than that of control from the stage of mature green to turning. The expression of ethylene response gene ERF1 and receptor gene LeETR1 and LeETR3 in fruit of breaker stage was significantly higher in transgenic line than in the control. 【Conclusion】 It was concluded from the study that the transformation of bzr1gene to tomato increased the content of various nutrients in fruit of turning stage, which is the edible part of tomato, and therefore improved the nutrient quality of tomato.

Key words: tomato, bzr1 gene, fruit, nutrient quality, signal transduction