Inactivation of a Gene Encoding Carotenoid Cleavage Dioxygenase (CCD4) Leads to Carotenoid-Based Yellow Coloration of Fruit Flesh and Leaf Midvein in Peach
Inactivation of a Gene Encoding Carotenoid Cleavage Dioxygenase (CCD4) Leads to Carotenoid-Based Yellow Coloration of Fruit Flesh and Leaf Midvein in Peach
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DOI：
10.1007/s11105-013-0650-8
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发表时间：
2014-02-01
影响因子：
2.1
通讯作者：
Han, Yuepeng
中科院分区：
文献类型：
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作者：
Ma, Juanjuan;Li, Jing;Han, Yuepeng
桃果肉黄色是桃果实的重要商品性状之一，是类胡萝卜素积累的结果。黄肉受单一基因座（Y）控制，其中白色肉比黄肉占优势。在这项研究中，Y基因座被缩小到2.6 cM的间隔两侧的两个标记，SSRy和W2691。SSRy基因位于类胡萝卜素裂解双加氧酶（CCD 4）基因的第一个外显子上，与Y基因座在两个桃F-1群体中共分离。RNA-Seq和qRT-PCR分析表明，桃果实中CCD 4的转录水平与类胡萝卜素的降解一致。这些结果表明，CCD 4是桃果肉白色和黄色着色的主要原因。在白肉桃果实中，类胡萝卜素被合成，但随后降解成无色化合物，导致形成白色颜色。在桃中，CCD 4可能利用β-胡萝卜素作为底物。有趣的是，CCD 4还控制桃叶片中脉的白色和黄色着色。此外，LCYE在桃叶中高度表达，而其转录本在果实中检测不到。这表明桃果实和叶片类胡萝卜素生物合成的差异。本研究不仅首次揭示了桃中CCD 4基因的多效性，而且为桃新品种的选育提供了一个形态标记，为桃的白色或黄色果肉的选育提供了一个新的途径。
Yellow fruit flesh color, resulting from the accumulation of carotenoids, is one of the most important commercial traits of peach. Yellow flesh is controlled by a single locus (Y), with white flesh dominant over yellow flesh. In this study, the Y locus was narrowed to a 2.6-cM interval flanked by two markers, SSRy and W2691. SSRy, which is located on the first exon of a gene encoding carotenoid cleavage dioxygenase (CCD4), was cosegregated with the Y locus in two peach F-1 populations. RNA-Seq and qRT-PCR analysis revealed transcript level of CCD4 was consistent with carotenoid degradation in peach fruits. All these results suggest that CCD4 is responsible for white and yellow coloration of peach fruit flesh. In fruits of white-fleshed peach, carotenoids are synthesized but subsequently degraded into colorless compounds, leading to the formation of white color. CCD4 is likely to utilize beta-carotene as the substrate in peach. Interestingly, CCD4 also controls white and yellow coloration of leaf midveins of peach. Moreover, LCYE was highly expressed in peach leaves, whereas its transcript was not detectable in fruits. This suggests the difference of carotenoid biosynthesis between peach fruits and leaves. Our study not only shows for the first time the pleiotropic effects of CCD4 gene in peach but also provides a morphological marker for easy selection of new peach cultivars with desirable white or yellow flesh colors.