Wang Xiaowen, Yang Chengkun, Zhu Wencan, Weng Zhongrui, Li Feili, Teng Yuanwen, Zhou Kaibing, Qian Minjie, Deng Qin
School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China.
Key Laboratory of Quality Regulation of Tropical Horticultural Crop in Hainan Province, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China.
Plants (Basel). 2024 Oct 17;13(20):2903. doi: 10.3390/plants13202903.
Pomegranate ( L.) is an ancient fruit crop that has been cultivated worldwide and is known for its attractive appearance and functional metabolites. Fruit color is an important index of fruit quality, but the color formation pattern in the peel of evergreen pomegranate and the relevant molecular mechanism is still unknown. In this study, the contents of pigments including anthocyanins, carotenoids, and chlorophyll in the peel of 'Danruo No. 1' pomegranate fruit during three developmental stages were measured, and RNA-seq was conducted to screen key genes regulating fruit color formation. The results show that pomegranate fruit turned from green to red during development, with a dramatic increase in value, indicating redness and anthocyanins concentration, and a decrease of chlorophyll content. Moreover, carotenoids exhibited a decrease-increase accumulation pattern. Through RNA-seq, totals of 30, 18, and 17 structural genes related to anthocyanin biosynthesis, carotenoid biosynthesis and chlorophyll metabolism were identified from differentially expressed genes (DEGs), respectively. Transcription factors (TFs) such as MYB, bHLH, WRKY and AP2/ERF were identified as key candidates regulating pigment metabolism by K-means analysis and weighted gene co-expression network analysis (WGCNA). The results provide an insight into the theory of peel color formation in evergreen pomegranate fruit.
石榴（Punica granatum L.）是一种古老的水果作物，已在全球范围内种植，以其诱人的外观和功能性代谢产物而闻名。果实颜色是果实品质的一个重要指标，但常绿石榴果皮的颜色形成模式及相关分子机制仍不清楚。本研究测定了‘丹若1号’石榴果实三个发育阶段果皮中花青素、类胡萝卜素和叶绿素等色素的含量，并通过RNA测序筛选调控果实颜色形成的关键基因。结果表明，石榴果实在发育过程中由绿色变为红色，a*值显著增加，表明红色和花青素浓度增加，叶绿素含量降低。此外，类胡萝卜素呈现出先减少后增加的积累模式。通过RNA测序，分别从差异表达基因（DEG）中鉴定出30个、18个和17个与花青素生物合成、类胡萝卜素生物合成和叶绿素代谢相关的结构基因。通过K均值分析和加权基因共表达网络分析（WGCNA），鉴定出MYB、bHLH、WRKY和AP2/ERF等转录因子（TF）是调控色素代谢的关键候选因子。该结果为常绿石榴果实果皮颜色形成理论提供了见解。
