Evolution of floral diversity: genomics, genes andgamma

Abstract

One contribution of 17 to a theme issue 'Evo-devo in the genomics era, and the origins of morphological diversity'. A salient feature of flowering plant diversification is the emergence of a novel suite of floral features coinciding with the origin of the most species-rich lineage, Pentapetalae. Advances in phylogenetics, developmental genetics and genomics, including new analyses presented here, are helping to reconstruct the specific evolutionary steps involved in the evolution of this clade. The enormous floral diversity among Pentapetalae appears to be built on a highly conserved ground plan of five-parted (pentamerous) flowers with whorled phyllotaxis. By contrast, lability in the number and arrangement of component parts of the flower characterize the early-diverging eudicot lineages subtending Pentapetalae. The diversification of Pentapetalae also coincides closely with ancient hexaploidy, referred to as the gamma whole-genome triplication, for which the phylogenetic timing, mechanistic details and molecular evolutionary consequences are as yet not fully resolved. Transcription factors regulating floral development often persist in duplicate or triplicate in gamma-derived genomes, and both individual genes and whole transcriptional programmes exhibit a shift from broadly overlapping to tightly defined expression domains in Pentapetalae flowers. Investigations of these changes associated with the origin of Pentapetalae can lead to a more comprehensive understanding of what is arguably one of the most important evolutionary diversification events within terrestrial plants.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.

Whole-Genome Duplication and Plant Macroevolution

“…These genes are implicated in the origin and diversification of the flower, a structure that has shaped recent plant and animal evolution [81]. The evolution of pentamerous flowers in the core eudicots also coincides with a genome triplication (gamma, Fig 1) [25,82]. The coincidence of the gamma event with this major synapomorphy, a large increase in the rate of diversification, and extensive genome reorganisation [58], makes it a tantalising system in which to investigate the link between WGD and morphological evolution.…”

“…Regulatory gene retention and large shifts in patterns of their transcription suggest a role for WGD in the evolution of eudicot floral diversity [82]. In order to make such a hypothesis testable, the increase in phenotypic complexity must be quantified for comparative analysis [83].…”

Nested whole-genome duplications coincide with diversification and high morphological disparity in Brassicaceae

“…These processes might be key to subsequent evolutionary success of respective clades evolving new traits and innovations. Some examples for key traits presumably originating from WGDs exist, such as synthesis of glucosinolates, secondary compounds involved in insect defense mechanisms in the order Brassicales, following At-β 21 or evolution of the pentamerous flower in Pentapetalae triggering plant-pollinator coevolution following At-γ 22 . However, there are few studies systematically linking morphological diversity and its evolution with WGDs 5 .…”

In memory of Professor Tang Yan‐Cheng: New perspectives in systematic and evolutionary biology

“…The results have led to a better understanding of relationships and evolution of the organisms with which we share our planet (Chase et al, 1993;San Mauro & Agorreta, 2010;Losos et al, 2013;Hinchliff et al, 2015;Soltis et al, 2018;Bakker et al, 2020). Moreover, recent efforts in reconstructing the tree of life, integrating methods and sharing data across disciplines, digitizing biological collections, harvesting big data from high-throughput DNA sequencing, and development of analytical and genetic tools (Wen et al, 2015(Wen et al, , 2017Soltis et al, 2018;Leebens-Mack et al, 2019;Bakker et al, 2020) have empowered systematic and evolutionary biology to undertake novel and integrative studies from perspectives that were previously impossible (e.g., Chanderbali et al, 2017;Ma et al, 2017aMa et al, , 2017bEllwood et al, 2018;Hodel et al, 2018;Landis et al, 2018;Lewin et al, 2018;Lu et al, 2018;Dong et al, 2019).…”