番茄合成虾青素的基因工程研究

	番茄合成虾青素的基因工程研究; Genetic engineering of tomato for the production of astaxanthin
	林渊源
导师	黄俊潮
摘要	Carotenoids are terpene compounds synthesized by all photosynthetic organisms where they play important roles in maintaining normal physiological functions. Carotenoids are also important for humans and animals. Tomato (Solanum lycopersicum) is a main source of carotenoids in human diet. With a small genome, clear genetic background, mature cultivation and transformation techniques, tomato has been an important model plant for carotenogenic research. This thesis focused on the genetic engineering of tomato for enhanced production of carotenoids including the high-value astaxanthin. In addition, a transformation system based on an algal phosphomannose isomerase (PMI) was assessed for the generation of transgenic tomato. Tomato has a unique mechanism to accumulate lycopene in the fruit. Lycopene β-cyclase (LCYB), β-carotene hydroxylase (BHY) and β-carotene ketolase (BKT) catalyze the conversion of lycopene to astaxanthin. This study first evaluated the co-expression of four genes linked by 2A sequences (crtB-2A-HpBHY-2A-CrBKT-2A-VsVHB) and driven by the CaMV35S promoter for separated translation of the four individual genes by introducing the expression cassette into tobacco. Ketocarotenoids including astaxanthin, canthaxanthin and ketolutein were synthesized in the leaves of transgenic tobacco, resulting in the change of leaf color from green to red and abnormal development of the plants which could not complete its life cycle. To overcome this problem, we replaced CaMV35S promoter and VsVHB gene with the fruit-specific promoter E8 and SlLCYB or AtOR, constructing constitutive and fruit-specific expressing cassettes crtB-HpBHY-CrBKT-AtOR (BBBO) and crtB-HpBHY-CrBKT-SlLCYB (BBBB). Micro-Tom tomato cells constitutive expressing BBBO or BBBB could generate red calluses with high contents of astaxanthin, but failed to produce seedlings. In contrast, Fruit-specific expression of BBBO and BBBB successfully gave rise to the generation of astaxanthin-producing transformants of both Micro-Tom and Huang Song tomato landraces that grew and developed normally. Transgenic “Micro-Tom” BBBO fruit accumulated 6-fold carotenoids including the novel astaxanthin (2.97 μg/g FW) of the control. Similarly, transgenic “Huang Song” BBBB fruit produced carotenoids up to 6.6 mg/g DW, which was about 44-fold of that in control and 3-fold of that in normal tomato fruits. In addition, astaxanthin (40.87 μg/g DW) was accumulated in the fruit. Furthermore, different generations (T0, T1, T2) of the transgenic lines, which planted in different environments and seasons, exhibited similar growing status and carotenoid profiles, indicating that the transformants were genetically stable and valuable for farming. That fruit-specific expression of exogenous genes minimized the interference of exogenous genes to endogenous metabolisms was found to be the key to the normal growth and development of transgenic plants. The expression of crtB compensated deficiency of phytoe
	2020-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74154
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	林渊源. 番茄合成虾青素的基因工程研究, Genetic engineering of tomato for the production of astaxanthin[D],2020.

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