As water-soluble, natural pigments, anthocyanins are responsible for the red, purple and blue colors of many flowers, which attract pollinators to spread pollen. The colors of flowers are also essential for plants to survive in the nature and become one of the most significant characteristics of ornamental plants. In the booming floriculture industry, to produce various flower colors could increase the richness of natural colors, but it is still difficult to breed flowers with coveted blue color. The diversity of flower color is mainly determined by the types and contents of anthocyanins and their derivatives. The synthesis of delphinidin pigments is the key factor for breeding blue flowers. However, there are no structural genes in many plants to biosynthesize delphinidin pigments. Blue flowers are successfully created by genetic engineering in recent years. In this paper, using common ornamental plants as examples, we review the mechanism of plant flower coloration from the aspects of the key factors affecting the synthesis of delphinidin pigment and the production strategies of blue flowers based on the regulation of anthocyanin metabolism. Different strategies of molecular breeding could provide opportunities to improve colors of other floriculture plants and to develop anthocyanin-rich economic crops, such as colored cotton with blue fibers.
花色是植物吸引昆虫传播花粉的主要因素，对于植物在自然界的生存必不可少，也是观赏植物最重要的性状之一。在蓬勃发展的花卉产业中，色彩各异花卉的培育，可以弥补自然花色的匮乏，但是令人垂涎的蓝色花比较难培育。花色的多样性主要是由花青素及其衍生物的种类和含量等因素决定的，飞燕草色素的合成是形成蓝色花的关键因素，许多植物体内缺少合成飞燕草色素的结构基因。近年来，利用基因工程技术培育蓝色花的研究也时有报道。文中以常见的观赏植物为例，基于花青素代谢调控，从影响飞燕草色素合成的关键因素和不同分子改良途径培育蓝色花等几个方面对植物花朵呈色的机制进行了综述，并展示不同分子育种策略可能在其他领域的应用，为其他植物或经济作物的色泽改良如彩色棉蓝色纤维的培育等提供参考和技术支持。.
Keywords: anthocyanin; bluish flower; flower color improvement; genetic engineering.