Lu Chenfei, Li Yajun, Cui Yumeng, Ren Jiangshan, Qi Fangting, Qu Jiaping, Huang He, Dai Silan
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Education Ministry, School of Landscape Architecture, Beijing Forestry University, Beijing, China.
Front Plant Sci. 2021 Feb 22;12:640746. doi: 10.3389/fpls.2021.640746. eCollection 2021.
Polyacylated anthocyanins with multiple glycosyl and aromatic acyl groups tend to make flowers display bright and stable blue colours. However, there are few studies on the isolation and functional characterization of genes involved in the polyacylated anthocyanin biosynthesis mechanism, which limits the molecular breeding of truly blue flowers. is an important potted ornamental plant, and its blue flowers contain 3',7-polyacylated delphinidin-type anthocyanins that are not reported in any other plants, suggesting that it harbours abundant gene resources for the molecular breeding of blue flowers. In this study, using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis of blue, carmine and white colours of cineraria cultivars "Venezia" (named VeB, VeC, and VeW, respectively), we found that 3',7-polyacylated anthocyanin, cinerarin, was the main pigment component that determined the blue colour of ray florets of cineraria. Based on the transcriptome sequencing and differential gene expression (DEG) analysis combined with RT- and qRT-PCR, we found two genes encoding uridine diphosphate glycosyltransferase, named and ; two genes encoding acyl-glucoside-dependent glucosyltransferases which belong to glycoside hydrolase family 1 (GH1), named and ; one gene encoding serine carboxypeptidase-like acyltransferase ; and two MYB transcriptional factor genes and , that were specifically highly expressed in the ray florets of VeB, which indicated that these genes may be involved in cinerarin biosynthesis. The function of was analysed by virus-induced gene silencing (VIGS) in cineraria leaves combined with HPLC-MS/MS. mainly participated in the 3' and 7-position acylation of cinerarin. These results will provide new insight into the molecular basis of the polyacylated anthocyanin biosynthesis mechanism in higher plants and are of great significance for blue flower molecular breeding of ornamental plants.
具有多个糖基和芳香酰基的多酰化花青素往往使花朵呈现明亮且稳定的蓝色。然而，关于参与多酰化花青素生物合成机制的基因的分离和功能表征的研究较少，这限制了真正蓝色花朵的分子育种。瓜叶菊是一种重要的盆栽观赏植物，其蓝色花朵含有3'，7 - 多酰化飞燕草素型花青素，这在其他任何植物中均未报道，表明它拥有丰富的用于蓝色花朵分子育种的基因资源。在本研究中，通过高效液相色谱 - 串联质谱（HPLC - MS/MS）对瓜叶菊品种“Venezia”的蓝色、洋红色和白色花朵（分别命名为VeB、VeC和VeW）进行分析，我们发现3'，7 - 多酰化花青素瓜叶菊素是决定瓜叶菊舌状花蓝色的主要色素成分。基于转录组测序和差异基因表达（DEG）分析，并结合RT - 和qRT - PCR，我们发现了两个编码尿苷二磷酸糖基转移酶的基因，分别命名为 和 ；两个编码属于糖苷水解酶家族1（GH1）的酰基 - 葡萄糖依赖性糖基转移酶的基因，分别命名为 和 ；一个编码丝氨酸羧肽酶样酰基转移酶的基因 ；以及两个MYB转录因子基因 和 ，它们在VeB的舌状花中特异性高表达，这表明这些基因可能参与瓜叶菊素的生物合成。通过在瓜叶菊叶片中进行病毒诱导基因沉默（VIGS）并结合HPLC - MS/MS对 的功能进行了分析。 主要参与瓜叶菊素的3'和7位酰化。这些结果将为高等植物中多酰化花青素生物合成机制的分子基础提供新的见解，对观赏植物蓝色花朵的分子育种具有重要意义。
