Hao Qing, Li Tongtong, Lu Gaojie, Wang Shuo, Li Zhen, Gu Cancan, Kong Fan, Shu Qingyan, Li Yang
College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao 266109, China.
College of Agricultural Science and Engineering, Liaocheng University, Liaocheng 252000, China.
J Adv Res. 2025 Jul;73:173-185. doi: 10.1016/j.jare.2024.09.003. Epub 2024 Sep 3.
Green flowers are not an adaptive trait in natural plants due to the challenge for pollinators to discriminate from leaves, but they are valuable in horticulture. The molecular mechanisms of green petals remain unclear. Tree peony (Paeonia suffruticosa) is a globally cultivated ornamental plant and considered the 'King of Flowers' in China. The P. suffruticosa 'Lv Mu Yin Yu (LMYY)' cultivar with green petals could be utilized as a representative model for understanding petal-specific chlorophyll (Chl) accumulation and color formation.
Identify the key genes related to Chl metabolism and understand the molecular mechanism of petal color changes.
The petal color parameter was analyzed at five developmental stages using a Chroma Spectrophotometer, and Chl and anthocyanin accumulation patterns were examined. Based on comparative transcriptomes, differentially expressed genes (DEGs) were identified, among which three were functionally characterized through overexpression in tobacco plants or silencing in 'LMYY' petals.
During flower development and blooming, flower color changed from green to pale pink, consistent with the Chl and anthocyanin levels. The level of Chl demonstrated a similar pattern with petal epidermal cell striation density. The DEGs responsible for Chl and anthocyanin metabolism were characterized through a comparative transcriptome analysis of flower petals over three critical developmental stages. The key chlorophyllase (PsCLH1) and light-harvesting chlorophyll a/b binding protein 1 (PsLhcb1) and PsLhcb5 influenced the Chl accumulation and the greenness of 'LMYY' petals.
PsCLH1, PsLhcb1, and PsLhcb5 were critical in accumulating the Chl and maintaining the petal greenness. Flower color changes from green to pale pink were regulated by the homeostasis of Chl degradation and anthocyanin biosynthesis. This study offers insights into underlying molecular mechanisms in the green petal and a strategy for germplasm innovation.
由于传粉者难以将绿色花朵与叶子区分开来，绿色花朵并非天然植物的适应性特征，但在园艺领域却颇具价值。绿色花瓣的分子机制尚不清楚。牡丹（Paeonia suffruticosa）是一种全球广泛种植的观赏植物，在中国被视为“花中之王”。具有绿色花瓣的牡丹品种‘绿幕隐玉（LMYY）’可作为理解花瓣特异性叶绿素（Chl）积累和颜色形成的代表性模型。
鉴定与叶绿素代谢相关的关键基因，并了解花瓣颜色变化的分子机制。
使用色度分光光度计分析花瓣在五个发育阶段的颜色参数，并检测叶绿素和花青素的积累模式。基于比较转录组，鉴定差异表达基因（DEGs），其中三个基因通过在烟草植株中过表达或在‘LMYY’花瓣中沉默进行功能表征。
在花朵发育和开放过程中，花色从绿色变为浅粉色，与叶绿素和花青素水平一致。叶绿素水平与花瓣表皮细胞条纹密度呈现相似模式。通过对花瓣在三个关键发育阶段的比较转录组分析，鉴定了负责叶绿素和花青素代谢的差异表达基因。关键叶绿素酶（PsCLH1）、光捕获叶绿素a/b结合蛋白1（PsLhcb1）和PsLhcb5影响了‘LMYY’花瓣的叶绿素积累和绿色度。
PsCLH1、PsLhcb1和PsLhcb5在叶绿素积累和维持花瓣绿色方面起关键作用。花色从绿色变为浅粉色受叶绿素降解和花青素生物合成的稳态调节。本研究为绿色花瓣潜在的分子机制提供了见解，并为种质创新提供了策略。
