不同PE材料遮光下血橙转色期果皮花色苷合成及其相关基因的表达分析

采用不同透光率的PE袋对转色期血橙果实进行遮光试验,测定了不同遮光处理下血橙果皮总花色苷的动态含量和血橙果皮中12个花色苷合成相关基因的动态表达,深入探究光照与血橙果皮花色苷着色之间的关系,以期为改善生产中血橙果面着色不良问题提供解决思路。结果表明:血橙果实经过PE袋遮光后,果皮在着色时间、着色面积和着色程度上均受到阻碍,阻碍程度与PE袋的透光率相关,遮光促进了血橙果面亮度的增加。自然光照下,8个结构基因GST、ANS、CHS、DFR、F3H、UFGT、PAL、4CL和2个调节基因Ruby、MYBF1在转色期间的表达量快速增加,而不同程度的遮光阻碍了其表达,阻碍程度与PE袋的透光率相关,推测这10个基因属于血橙果皮花色苷合成受光调控的关键基因。将遮光后果皮总花色苷动态含量、关键基因的动态表达量与对应的PE袋透光数据进行综合分析,可以推测光照中调控血橙果皮花色苷合成的可能是其中的UVB、UVC紫外光。根据相关基因的动态测定结果,推测血橙果皮花色苷合成的关键时期在花后249 d开始出现,为保证外观品质,血橙采摘在花后249 d之后进行较为适宜。为预防血橙冬季落果,生产上通常采用冬季树体覆膜技术保果,为减少覆膜对血橙果面花色苷着色的影响,应选用透明PE膜或其他紫外线透过率较高的膜。

Analysis of anthocyanin synthesis and related gene expression in blood orange peel under different PE materials shading during fruit coloring period

To explore the relationship between light and anthocyanin synthesis of blood orange peel,some PE bags with different light transmittance was used to perform shading experiments on the fruit during the ripening period. This experiment determined the dynamic content of total anthocyanins and the dynamic expression of 12 anthocyanin synthesis-related genes in blood orange peels under different shading treatments. The results showed that coloring time, coloring area and coloring degree of the blood orange fruit were hindered by different degrees of shading. The degree of obstruction was related to the light transmittance of the PE bags, but the PE bags shading promoted the increase of the brightness of the blood orange fruit surface. In the natural state,the expression of 8 structural genes GST, ANS, CHS, DFR, F3H, UFGT, PAL, 4CL and two regulatory genes Ruby and MYBF1 showed a rapid increase during the color conversion period, and different degrees of shading hindered them. So these 10 genes were the key genes of blood orange peel anthocyanin synthesis regulated by light. After the comprehensive analysis of the dynamic content of total anthocyanins, the dynamic expression of key genes and the corresponding PE bags light transmittance data, it could be inferred that the UVB ultraviolet light might regulate the synthesis of blood orange peel anthocyanins in the light. According to the dynamic determination results of related genes, it was speculated that the critical period of blood orange peel anthocyanin synthesis appeared on 249 d after flowering. For better appearance quality, it was more appropriate to pick blood oranges on 249 d after flowering. Transparent PE film or other films with higher UV transmittance should be used to protect the fruit of blood orange in winter.