The Phytoene synthase gene family of apple (Malus x domestica) and its role in controlling fruit carotenoid content.
The Phytoene synthase gene family of apple (Malus x domestica) and its role in controlling fruit carotenoid content.
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DOI：
10.1186/s12870-015-0573-7
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发表时间：
2015-07-28
影响因子：
5.3
通讯作者：
Allan AC
中科院分区：
文献类型：
--
作者：
Ampomah-Dwamena C;Driedonks N;Lewis D;Shumskaya M;Chen X;Wurtzel ET;Espley RV;Allan AC
类胡萝卜素化合物在植物中发挥着重要的作用，如保护光合作用装置和激素信号。有色类胡萝卜素为植物组织提供黄色、橙色和红色，并为人类和动物提供营养益处。植烯合成酶(PSY)催化类胡萝卜素生物合成途径的第一步，并与途径通量的控制有关。我们对在苹果基因组中发现的四个PSY基因进行了表征，以进一步了解它们与果实类胡萝卜素积累的关系。根据预测的基因序列和/或相应的cDNA的翻译，苹果PSY基因家族包含6个成员，预测有3个功能成员，PSY1，PSY2和智力4。然而，只有PSY1和PSY2在互补实验中显示了活性。蛋白质定位实验表明，PSY蛋白在叶绿体中的定位不同；PSY1和PSY2定位于类囊体膜，而PSY4定位于质球蛋白。在‘奶奶史密斯’和‘皇家嘎拉’苹果品种中的转录水平表明，PSY2在果实和其他营养组织中表达最高。我们测试了苹果PSY1和PSY2启动子的瞬时激活，并确定了AP2/ERF转录因子对PSY基因的潜在调控和差异调控，这表明PSY基因受不同的转录机制控制。苹果类胡萝卜素途径的第一步是由MdPSY1和MdPSY2控制的，而MdPSY4在这方面几乎或根本不起作用。这对以类胡萝卜素增强为目标的苹果育种计划有影响，并将允许在新品种开发期间测试与表型的共分离。本文的在线版本(doi：10.1186/s12870-0150573-7)包含补充材料，授权用户可以使用。
Carotenoid compounds play essential roles in plants such as protecting the photosynthetic apparatus and in hormone signalling. Coloured carotenoids provide yellow, orange and red colour to plant tissues, as well as offering nutritional benefit to humans and animals. The enzyme phytoene synthase (PSY) catalyses the first committed step of the carotenoid biosynthetic pathway and has been associated with control of pathway flux. We characterised four PSY genes found in the apple genome to further understand their involvement in fruit carotenoid accumulation. The apple PSY gene family, containing six members, was predicted to have three functional members, PSY1, PSY2, and PSY4, based on translation of the predicted gene sequences and/or corresponding cDNAs. However, only PSY1 and PSY2 showed activity in a complementation assay. Protein localisation experiments revealed differential localization of the PSY proteins in chloroplasts; PSY1 and PSY2 localized to the thylakoid membranes, while PSY4 localized to plastoglobuli. Transcript levels in ‘Granny Smith’ and ‘Royal Gala’ apple cultivars showed PSY2 was most highly expressed in fruit and other vegetative tissues. We tested the transient activation of the apple PSY1 and PSY2 promoters and identified potential and differential regulation by AP2/ERF transcription factors, which suggested that the PSY genes are controlled by different transcriptional mechanisms. The first committed carotenoid pathway step in apple is controlled by MdPSY1 and MdPSY2, while MdPSY4 play little or no role in this respect. This has implications for apple breeding programmes where carotenoid enhancement is a target and would allow co-segregation with phenotypes to be tested during the development of new cultivars. The online version of this article (doi:10.1186/s12870-015-0573-7) contains supplementary material, which is available to authorized users.