Wang Yiting, Li Shaopeng, Zhu Ziqi, Xu Zongda, Qi Shuai, Xing Shutang, Yu Yunyan, Wu Qikui
Shandong Provincial Research Center of Demonstration Engineering Technology for Urban and Rural Landscape, College of Forestry, Shandong agricultural University, Tai'an, China.
School of Landscape Architecture, Beijing Forestry University, Beijing, China.
Front Plant Sci. 2022 Sep 23;13:1021521. doi: 10.3389/fpls.2022.1021521. eCollection 2022.
is a famous Chinese traditional flower with high ornamental value and well environmental adapt ability. The cultivation of new colorful germplasms to improve monotonous flower color could promote its landscape application. However, the mechanism of flower color formation in remains unclear. In this study, combined analyses of the chemical and transcriptome were performed in the germplasms with representative flower colors. Among the identified anthocyanins, cyanidin 3,5--diglucoside (Cy3G5G) and peonidin 3,5--diglucoside (Pn3G5G) were the two dominant anthocyanins in the petals of . The sum content of Cy3G5G and Pn3G5G was responsible for the petal color intensity, such as pink or purple, light- or dark- red. The ratio of Cy3G5G to Pn3G5G was contributed to the petal color hue, that is, red or pink/purple. Maintaining both high relative and high absolute content of Cy3G5G may be the precondition for forming red-colored petals in . Cyanidin biosynthesis shunt was the dominant pathway for anthocyanin accumulation in , which may be the key reason for the presence of monotonous petal color in , mainly pink/purple. In the upstream pathway of cyanidin biosynthesis, 35 differentially expressed structural genes encoding 12 enzymes co-expressed to regulate the sum contents of Cy3G5G and Pn3G5G, and then determined the color intensity of petals. , involved in the downstream pathway of cyanidin biosynthesis, regulated the ratio of Cy3G5G to Pn3G5G methylation and then determined the color hue of petals. It was worth mentioning that significantly higher delphinidin-3,5--diglucoside content and expression were detected from deep purple-red-flowered 8-16 germplasm with somewhat unique and visible blue hue. Three candidate key transcription factors identified by correlation analysis, , , and , might play critical roles in the control of petal color by regulating the expression of both and other multiple structural genes. These results provided novel insights into anthocyanin accumulation and flower coloration mechanism in , and the candidate key genes involved in anthocyanin biosynthesis could be valuable resources for the breeding of ornamental plants in future.
是一种著名的中国传统花卉，具有很高的观赏价值和良好的环境适应能力。培育新的彩色种质以改善单一的花色可促进其在园林中的应用。然而，其花色形成机制尚不清楚。本研究对具有代表性花色的种质进行了化学和转录组联合分析。在鉴定出的花青素中，矢车菊素3,5 - 二葡萄糖苷（Cy3G5G）和芍药色素3,5 - 二葡萄糖苷（Pn3G5G）是该种花花瓣中的两种主要花青素。Cy3G5G和Pn3G5G的总含量决定了花瓣颜色的深浅，如粉色或紫色、浅红色或深红色。Cy3G5G与Pn3G5G的比例决定了花瓣颜色的色调，即红色或粉红/紫色。保持Cy3G5G的高相对含量和高绝对含量可能是该种花形成红色花瓣的前提条件。矢车菊素生物合成支路是该种花中花青素积累的主要途径，这可能是该种花花瓣颜色单一（主要为粉红/紫色）的关键原因。在矢车菊素生物合成的上游途径中，35个编码12种酶的差异表达结构基因共同表达以调节Cy3G5G和Pn3G5G的总含量，进而决定花瓣的颜色深浅。参与矢车菊素生物合成下游途径，通过甲基化调节Cy3G5G与Pn3G5G的比例，进而决定花瓣的颜色色调。值得一提的是，在具有 somewhat 独特且可见蓝色调的深紫红色花8 - 16种质中检测到了显著更高的飞燕草素 - 3,5 - 二葡萄糖苷含量和表达。通过相关性分析鉴定出的三个候选关键转录因子，、和，可能通过调节和其他多个结构基因的表达在花瓣颜色控制中发挥关键作用。这些结果为该种花中花青素积累和花色形成机制提供了新的见解，参与花青素生物合成的候选关键基因可能是未来观赏植物育种的宝贵资源。
