Transcriptional-Metabolic Networks in β-Carotene-Enriched Potato Tubers: The Long and Winding Road to the Golden Phenotype
Transcriptional-Metabolic Networks in β-Carotene-Enriched Potato Tubers: The Long and Winding Road to the Golden Phenotype
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DOI：
10.1104/pp.110.159368
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发表时间：
2010-10-01
期刊：
影响因子：
7.4
通讯作者：
Giuliano, Giovanni
中科院分区：
文献类型：
--
作者：
Diretto, Gianfranco;Al-Babili, Salim;Giuliano, Giovanni
维生素A缺乏症是许多国家的一个公共卫生问题。用β-胡萝卜素对主要主食作物（小麦[Triticum aestivum]、水稻[Oryza sativa]、玉米[Zea mays]和马铃薯[Solanum tuberosum]）进行生物强化有可能缓解这一营养问题。以前，我们设计了过表达三种细菌基因的转基因“金色”马铃薯块茎，用于β-胡萝卜素合成（CrtB，CrtI和CrtY，分别编码八氢番茄红素合成酶，八氢番茄红素去饱和酶和番茄红素β-环化酶），并在上述四种作物中积累了最高量的β-胡萝卜素。在这里，我们报告的类胡萝卜素的代谢产物和成绩单在24行携带6个不同的转基因组合的控制下的35 S和Patatin（帕特）启动子的系统定量。低水平的B-I表达足以干扰叶胡萝卜素生成，但不能干扰块茎和愈伤组织中的β-胡萝卜素积累，这需要在Pat启动子的控制下所有三个基因的高表达水平。表达B-I转基因的块茎在内源性类胡萝卜素基因的转录中显示出大的扰动，类胡萝卜素含量只有微小的变化，而在金色（Y-B-I）块茎中观察到相反的表型（低水平的转录扰动和高水平的类胡萝卜素水平）。我们使用层次聚类和成对相关分析，以及一种新的方法，网络相关分析，为此目的而开发的，以评估在转基因叶片和块茎的转录和代谢物水平的扰动。通过“内疚的剖析”的方法，我们确定了几个内源性基因类胡萝卜素的生物合成可能发挥关键的调控作用，在黄金块茎，这是候选人的操纵，旨在进一步优化块茎类胡萝卜素含量。
Vitamin A deficiency is a public health problem in a large number of countries. Biofortification of major staple crops (wheat [Triticum aestivum], rice [Oryza sativa], maize [Zea mays], and potato [Solanum tuberosum]) with beta-carotene has the potential to alleviate this nutritional problem. Previously, we engineered transgenic "Golden" potato tubers overexpressing three bacterial genes for beta-carotene synthesis (CrtB, CrtI, and CrtY, encoding phytoene synthase, phytoene desaturase, and lycopene beta-cyclase, respectively) and accumulating the highest amount of beta-carotene in the four aforementioned crops. Here, we report the systematic quantitation of carotenoid metabolites and transcripts in 24 lines carrying six different transgene combinations under the control of the 35S and Patatin (Pat) promoters. Low levels of B-I expression are sufficient for interfering with leaf carotenogenesis, but not for beta-carotene accumulation in tubers and calli, which requires high expression levels of all three genes under the control of the Pat promoter. Tubers expressing the B-I transgenes show large perturbations in the transcription of endogenous carotenoid genes, with only minor changes in carotenoid content, while the opposite phenotype (low levels of transcriptional perturbation and high carotenoid levels) is observed in Golden (Y-B-I) tubers. We used hierarchical clustering and pairwise correlation analysis, together with a new method for network correlation analysis, developed for this purpose, to assess the perturbations in transcript and metabolite levels in transgenic leaves and tubers. Through a "guilt-by-profiling" approach, we identified several endogenous genes for carotenoid biosynthesis likely to play a key regulatory role in Golden tubers, which are candidates for manipulations aimed at the further optimization of tuber carotenoid content.