Zhao Da-Qiu, Wei Meng-Ran, Liu Ding, Tao Jun
Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, PR China; Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, PR China.
Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, PR China; Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, PR China.
Plant Physiol Biochem. 2016 May;102:97-106. doi: 10.1016/j.plaphy.2016.02.023. Epub 2016 Feb 18.
Herbaceous peony (Paeonia lactiflora Pall.) is particularly appreciated because of its elegant and gorgeous flower color, but little is known about the underlying mechanisms of flower coloration. In this study, three P. lactiflora cultivars 'Xuefeng', 'Fenyulou' and 'Dahonglou' with white, pink and red flower were selected as the materials. Their anatomical structures, cell sap pH and metal elements were investigated, and the colored pigment mainly distributed in palisade mesophyll was only found in 'Fenyulou' and 'Dahonglou', and their shape of epidermal cells, cell sap pH and metal elements were not the key factors deciding phenotype color. Moreover, the qualitative and quantitative analysis of flavonoids were performed, their total anthocyanin, anthoxanthin and flavonoid contents were decreased during flower development, and only anthocyanin content in 'Dahonglou' was always higher than that in 'Xuefeng' and 'Fenyulou'. Subsequently, three anthocyanin compositions were found, and peonidin 3,5-di-O-glucoside (Pn3G5G) was identified as the main anthocyanin composition. In addition, the full-length of flavonol synthase gene (FLS) was isolated with the GenBank accession number KM259902, and the expression patterns of eight flavonoid biosynthetic genes showed that only PlDFR and PlANS basically had the highest levels in 'Dahonglou' and the lowest levels in 'Xuefeng', and they basically displayed a descended trend during flower development especially PlDFR, suggesting that these two genes might play a key role in the anthocyanin biosynthesis which resulted in the shift from white to pink and red in flowers. These results would contribute to understand the underlying molecular mechanisms of flower coloration in P. lactiflora.
芍药（Paeonia lactiflora Pall.）因其优雅艳丽的花色而备受青睐，但关于其花色形成的潜在机制却知之甚少。本研究选取了三个芍药品种‘雪峰’、‘粉玉楼’和‘大红楼’，它们的花色分别为白色、粉色和红色。对其解剖结构、细胞液pH值和金属元素进行了研究，结果发现，仅在‘粉玉楼’和‘大红楼’中发现了主要分布在栅栏叶肉中的有色色素，它们的表皮细胞形状、细胞液pH值和金属元素并非决定表型颜色的关键因素。此外，对黄酮类化合物进行了定性和定量分析，在花朵发育过程中，它们的总花青素、黄酮和黄酮醇含量均有所下降，只有‘大红楼’中的花青素含量始终高于‘雪峰’和‘粉玉楼’。随后，发现了三种花青素成分，其中芍药色素-3,5-二-O-葡萄糖苷（Pn3G5G）被鉴定为主要的花青素成分。此外，分离得到了黄酮醇合酶基因（FLS）的全长序列，GenBank登录号为KM259902，八个类黄酮生物合成基因的表达模式表明，只有PlDFR和PlANS在‘大红楼’中的表达水平基本最高，在‘雪峰’中的表达水平基本最低，且在花朵发育过程中基本呈下降趋势，尤其是PlDFR，这表明这两个基因可能在花青素生物合成中起关键作用，导致花朵颜色从白色转变为粉色和红色。这些结果将有助于理解芍药花色形成的潜在分子机制。
