背景回顾：Species of the tribe Delphinieae (Ranunculaceae) have long been the focus of morphological, ecological and evolutionary studies due to their highly specialized, nearly zygomorphic (bilaterally symmetrical) spiral flowers with nested petal and sepal spurs and reduced petals. 

提出问题：The mechanisms underlying the development and evolution of Delphinieae flowers, however, remain unclear. 

主要发现：Here, by conducting extensive phylogenetic, comparative transcriptomic, expression, and functional studies, we clarified the evolutionary histories, expression patterns, and functions of floral organ identity and symmetry genes in Delphinieae. 

结果1-花器官对称基因的复制与功能多样化：We found that duplication and/or diversification of APETALA3-3 (AP3-3), AGAMOUS-LIKE6 (AGL6), CYCLOIDEA (CYC) and DIVARICATA (DIV) lineage genes was tightly associated with the origination of Delphinieae flowers. 

结果2-AGL6-1a和AGL6-1b功能冗余：Specifically, an AGL6-lineage member (such as the Delphinium ajacis AGL6-1a) represses sepal spur formation and petal development in the lateral and ventral parts of the flower while determining petal identity redundantly with AGL6-1b. 

结果3-CYC2a和CYC2b功能分化：By contrast, two CYC2-like genes, CYC2b and CYC2a, define the dorsal and lateral-ventral identities of the flower, respectively, and form complex regulatory links with AP3-3, AGL6-1a and DIV1. 

结论：Therefore, duplication and diversification of floral symmetry genes, as well as co-option of the duplicated copies into the pre-existing floral regulatory network, have been key for the origin of Delphinieae flowers.

 摘 要 

毛茛科翠雀族的植物由于其高度特化的、几乎双侧对称的螺旋状花，内嵌的花瓣和萼矩以及减少的萼片，在形态、生态和演化层面上广受关注。翠雀族的花发育和演化的潜在分子机制一直是个谜。本文中，作者通过系统发育、比较转录组、表达和功能研究，揭示了翠雀族植物中花器官决定基因和对称基因的演化历史、表达模式以及功能。作者发现AP3-3、AGL6、CYC和DIV谱系基因的复制和/或功能多样化与翠雀族植物花的起源密切相关。尤其是，AGL6系基因，比如飞燕草中的AGL6-1a能够抑制花侧面和腹侧的萼矩形成和花瓣发育，而与AGL6-1b基因功能冗余地决定花瓣特性。相反，两个CYC2-like基因CYC2b和CYC2a分别决定了背侧和侧腹的花特性，与AP3-3、AGL6-1a和DIV1形成复杂的调控关联。因此，花器官对称基因的复制和功能多样化，以及复制基因对整合进已存在的花调控网络，共同决定了翠雀族植物的花起源和演化。

** 山红艳 **