Data Sheet 1_UV radiation promotes anthocyanins biosynthesis in the fruit peel of blood oranges (Citrus sinensis).doc

IntroductionThe commercial value of blood oranges (Citrus sinensis) is closely linked to the intensity of red pigmentation in the peel and flesh, driven by the accumulation of anthocyanins. While light is a crucial environmental factor for anthocyanin synthesis, the specific effects of different light spectra, particularly ultraviolet (UV) radiation, on peel pigmentation have not been fully elucidated.
MethodsIn this study, the effects of light spectra on anthocyanin biosynthesis in blood orange peel were systematically studied through three treatments of visible light (VL), UV and complete shading (CK). These treatments were combined with transcriptome, anthocyanin targeted metabolome and weighted gene coexpression network analysis (WGCNA).
Results and DiscussionAfter 40 days, UV-treated fruit exhibited significantly higher anthocyanin content and color index (CI) than other treatments, with a significantly positive correlation between the two. Metabolomics identified four key anthocyanins, including cyanidin-3-o-glucoside and its 2 derivatives, as the primary contributors to pericarp coloration, with their levels significantly increased under UV exposure. WGCNA screened three core gene modules closely associated with anthocyanin metabolism, and further identified three glycosyltransferase genes (ugt79b1, bz1 and GT1) as hub genes involved in anthocyanin accumulation. This study demonstrates that UV light enhanced anthocyanin synthesis in blood orange peel by activating downstream glycosylation pathways, providing both a theoretical basis and technical approach for improving commercially market value of blood orange through light regulation.

引言 血橙（Citrus sinensis）的商业价值与其果皮、果肉的红色着色强度密切相关，而该着色过程由花青素的积累所驱动。光是花青素合成的关键环境因子，但不同光谱尤其是紫外（UV）辐射对果皮着色的具体调控效应尚未完全阐明。
方法 本研究设置可见光（VL）、紫外（UV）及全遮光（CK）三组处理，系统探究光光谱对血橙果皮花青素生物合成的影响。本研究结合转录组学、花青素靶向代谢组学与加权基因共表达网络分析（WGCNA）开展相关实验。
结果与讨论 处理40天后，紫外处理组果实的花青素含量与色泽指数（CI）均显著高于其他处理组，且二者呈显著正相关。代谢组学分析鉴定出4种关键花青素（包括矢车菊素-3-O-葡萄糖苷及其2种衍生物）为果皮着色的主要物质基础，紫外暴露下这些物质的含量显著升高。WGCNA筛选出3个与花青素代谢紧密相关的核心基因模块，并进一步鉴定出3个糖基转移酶基因（ugt79b1、bz1和GT1）作为参与花青素积累的枢纽基因。本研究证实，紫外辐射可通过激活下游糖基化通路促进血橙果皮的花青素合成，为通过光调控手段提升血橙商业价值提供了理论依据与技术路径。