利用苹果转基因愈伤组织研究类胡萝卜素积累影响花青苷合成的机理

类胡萝卜素和花青苷均是植物至关重要的抗氧化类色素，与人体健康也息息相关。以往的研究多是针对其中一种开展，而对类胡萝卜素和花青苷间的积累关系了解甚少。植物中是否存在一种调控两者间积累关系的生物学机制，还不得而知。申请人前期通过超表达八氢番茄红素合成酶基因获得高水平积累类胡萝卜素的苹果愈伤组织。与非转基因愈伤组织相比，转基因愈伤组织在光照条件下的花青苷积累水平显著减少，花青苷合成基因的表达也相应降低。已知氧化还原反应同类胡萝卜素和花青苷均有一定联系，它是否可能正是建立两者间相关性的关键环节？基于此，本项目拟首先通过生化、基因和蛋白分析，揭示类胡萝卜素通过调控愈伤组织氧化还原反应，进而削弱花青苷合成调控因子对光信号的响应；进一步通过数字表达谱挖掘类胡萝卜素积累影响花青苷合成的分子调控机制。本项目将为理解植物中类胡萝卜素和花青苷的积累关系提供重要的理论依据，并为苹果果实色泽改良奠定一定的理论基础。

Carotenoids and anthocyanins represent two groups of the essential antioxidants in plants, and also protect human health. Considerable researches with regard to only one group have been performed, but there is a limited understanding on the correlation between carotenoids and anthocyanins during their accumulation processes. It is not known whether there is a biological mechanism that can construct the correlation between carotenoids and anthocyanins. In our previous study, the transgenic apple calli with high level of carotenoids were constructed by over-expressing the phytoene synthase gene. Unlike the non-transgenic callus that accumulated abundant anthocyanins, the transgenic one showed a declined anthocyanin accumulation and the suppressed transcriptions of anthocyanin biosynthetic genes. Previous studies have shown the connection of redox to both of carotenoids and anthocyanins, the question is raised whether redox can play the key role in constructing the correlation between carotenoids and anthocyanins. To prove it, biochemical, genetic and protein analysis will be firstly applied to clarify the role of carotenoids in the redox regulation, which will disturb the response of anthocyanin biosynthesis to light. Furthermore, through the genome-wild analysis based on the Digital Gene Expression Profiling, we will try to discover the transcriptional mechanism involving in the negative effect of carotenoid accumulation on anthocyanin biosynthesis. Expected results from this study will help provide a theoretical basis for further understanding of the correlation between carotenoids and anthocyanins in plants, and for quality improvement in future apple breeding programs.