Genetics of flower development in Ranunculales – a new, basal eudicot model order for studying flower evolution

Abstract

Contents 361I.361II.362III.363IV.364V.364Acknowledgements365References365 Summary Ranunculales, the sister group to all other eudicots, encompasses species with a remarkable floral diversity, which are currently emerging as new model organisms to address questions relating to the genetic architecture of flower morphology and its evolution. These questions concern either traits only found in members of the Ranunculales or traits that have convergently evolved in other large clades of flowering plants. We present recent results obtained on floral organ identity and number, symmetry evolution and spur formation in Ranunculales species. We discuss benefits and future prospects of evo‐devo studies in Ranunculales, which can provide the opportunity to decipher the genetic architecture of novel floral traits and also to appraise the degree of conservation of genetic mechanisms involved in homoplasious traits.

Ultrastructure and optics of the prism‐like petal epidermal cells of Eschscholzia californica (California poppy)

“…Recent observations of Adonis aestivalis (Ranunculaceae -Ranunculales) show that the epidermal cells are evenly thickened and shallowly domed, with parallel surface striations (Moyroud et al, 2017). Thus, the early-divergent eudicot order Ranunculales, which is critical in understanding trait evolution in eudicots, displays considerable New Phytologist diversity not only in overall flower structure (Damerval & Becker, 2017), but also in ultrastructural aspects of the petal epidermis.…”

“…Phylogenetic placement of Eschscholzia in the early-divergent eudicot order Ranunculales makes it an emerging model species in comparative evolutionary studies (e.g. Barakat et al, 2007;Hidalgo & Gleissberg, 2010;Lange et al, 2013;Damerval & Becker, 2017). The large solitary flowers typically bear four petals that are orange or yellow, owing to the presence of carotenoids, although flower colour variants ranging from white to red are common (Becker et al, 2005;Barrell et al, 2010).…”

Evolutionary diversification of CYC/TB1‐like TCP homologs and their recruitment for the control of branching and floral morphology in Papaveraceae (basal eudicots)

“…Ranunculales, the sister group to all other eudicots, has been established as a new model order to understand flower morphological diversification (Damerval & Becker, 2017). Its phylogenetic position in angiosperms makes it an ideal target for studies aiming at the elucidation of the origin, evolution and diversification of gene functions in flowers (Becker, 2016;Chanderbali et al, 2016).…”

Grass flowers: An untapped resource for floral evo‐devo

“…Multiple model systems in single lineages (orders, families, genera) hold the most promise for detailed insight into the evolutionary molecular genetics of development above the species level (Chanderbali et al, 2016;Damerval & Becker, 2017). This has been clearly illustrated in the Brassicaceae, where functional comparisons between arabidopsis and Cardamine hirsuta L. have led to significant insights into the molecular evolution underlying leaf and fruit form (Hay & Tsiantis, 2006;Vlad et al, 2014;Hofhuis et al, 2016).…”

“…This has been clearly illustrated in the Brassicaceae, where functional comparisons between arabidopsis and Cardamine hirsuta L. have led to significant insights into the molecular evolution underlying leaf and fruit form (Hay & Tsiantis, 2006;Vlad et al, 2014;Hofhuis et al, 2016). In the eudicots, the Brassicaceae and Ranunculaceae each include multiple established or emerging systems that vary in key morphological traits (Kramer, 2009;Canales et al, 2010;Damerval & Becker, 2017). Studies in these systems allow for the precise dissection of gene function and for making strong connections between molecular and morphological evolution (e.g., Sharma & Kramer, 2013;Vlad et al, 2014).…”