Elomaa Paula, Zhao Yafei, Zhang Teng
Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014 Helsinki, Finland.
Hortic Res. 2018 Jul 1;5:36. doi: 10.1038/s41438-018-0056-8. eCollection 2018.
Inflorescences in the Asteraceae plant family, flower heads, or capitula, mimic single flowers but are highly compressed structures composed of multiple flowers. This transference of a flower-like appearance into an inflorescence level is considered as the key innovation for the rapid tribal radiation of Asteraceae. Recent molecular data indicate that Asteraceae flower heads resemble single flowers not only morphologically but also at molecular level. We summarize this data giving examples of how rewiring of conserved floral regulators have led to evolution of morphological innovations in Asteraceae. Functional diversification of the highly conserved flower meristem identity regulator LEAFY has shown a major role in the evolution of the capitulum architecture. Furthermore, gene duplication and subsequent sub- and neofunctionalization of - and like genes in Asteraceae have been shown to contribute to meristem determinacy, as well as flower type differentiation-key traits that specify this large family. Future challenge is to integrate genomic, as well as evolutionary developmental studies in a wider selection of Asteraceae species to understand the detailed gene regulatory networks behind the elaborate inflorescence architecture, and to promote our understanding of how changes in regulatory mechanisms shape development.
菊科植物的花序，即头状花序，形似单花，但实际上是由多朵花高度压缩而成的结构。这种从花状外观到花序层面的转变被认为是菊科快速族系辐射的关键创新。最近的分子数据表明，菊科的头状花序不仅在形态上，而且在分子水平上都类似于单花。我们总结了这些数据，并举例说明了保守的花调控因子的重新连接如何导致菊科形态创新的进化。高度保守的花分生组织身份调控因子LEAFY的功能多样化在头状花序结构的进化中发挥了重要作用。此外，菊科中与 - 和 类似基因的基因复制以及随后的亚功能化和新功能化已被证明有助于分生组织的确定性以及花型分化，这些关键性状界定了这个大家族。未来的挑战是在更广泛的菊科物种中整合基因组学以及进化发育研究，以了解复杂花序结构背后详细的基因调控网络，并增进我们对调控机制变化如何塑造发育的理解。
