Department of Postharvest Science of Fresh Produce , ARO, The Volcani Center , P.O. Box 15159, Rishon LeZion 7505101 , Israel.
Faculty of Agricultural, Food and Environmental Quality Sciences , Hebrew University of Jerusalem , Rehovot 76100 , Israel.
J Agric Food Chem. 2019 May 1;67(17):4800-4807. doi: 10.1021/acs.jafc.9b00669. Epub 2019 Apr 16.
To identify factors governing peel-color development in mandarins, we examined carotenoid content and composition and the expression of carotenoid-related genes during four stages of ripening (i.e., green, breaker, yellow, and orange) in two varieties: 'Ora', which has orange fruit, and 'Shani', which has orange-reddish fruit. The two varieties had different carotenoid compositions, and 'Shani' had a significantly higher level of total carotenoid pigments. 'Shani' was rich in the deep orange β-cryptoxanthin and the orange-reddish β-citraurin, whereas 'Ora' was rich in the orange violaxanthin. RNA-Seq analysis revealed significantly greater expression of the carotenoid-biosynthesis genes PSY, βLCY, βCHX, and CCD4b, as well as MEP-pathway genes and several ethylene-biosynthesis and -signaling genes in 'Shani' fruit. In contrast, the expression levels of genes involved in the synthesis of α-branch carotenoids (i.e., εLCY and εCHX) and ZEP, which is involved in the formation of violaxanthin, were significantly higher in the 'Ora' fruit.
为了确定控制蜜柑果皮颜色发育的因素，我们在两个品种（即'Ora'，其果实为橙色，和 'Shani'，其果实呈橙红色）的四个成熟阶段（即绿色、转色期、黄色和橙色）中，检查了类胡萝卜素的含量和组成以及与类胡萝卜素相关基因的表达。这两个品种的类胡萝卜素组成不同，而 'Shani' 的总类胡萝卜素色素含量显著更高。'Shani' 富含深橙色的 β-隐黄质和橙红色的 β-柠乌素，而 'Ora' 则富含橙色的玉米黄质。RNA-Seq 分析表明，'Shani' 果实中类胡萝卜素生物合成基因 PSY、βLCY、βCHX 和 CCD4b 以及 MEP 途径基因和几个乙烯生物合成和信号转导基因的表达显著更高。相比之下，参与合成 α-支链类胡萝卜素（即 εLCY 和 εCHX）和 ZEP 的基因的表达水平，以及涉及玉米黄质形成的基因的表达水平，在 'Ora' 果实中显著更高。
