Format: ORAL

Yue Yang1, Jianjun Jin1, Deren Eaton1

1 Ecology, Evolution and Environmental Biology Department, Columbia University, New York, USA

Floral color, one of the conspicuous phenotypic traits in plants, exhibits a wide spectrum of variations. Color variations are mainly determined by the types, combinations and concentrations of different pigments. The underlying genetic pathways of pigment production have been well-studied and are relatively conserved across species. However, the evolutionary and genetic mechanisms driving the interspecific floral color variations, particularly in lineages such as Pedicualris, remain elusive. Pedicularis has over 500 species worldwide and over two-thirds are distributed in Hengduan Mountain, a recognized biodiversity hotspot. This plant genus has an exceptional diversity in floral color with a range encompassing white, yellow, red, purple and their combinations. A particular intriguing aspect of this genus is its floral color convergence, where similar color patterns recur in multiple independent lineages. It is unclear how independent mutations (genetic convergence), inheritance of ancestral polymorphisms and introgressions contribute to the observed convergence. Moreover, if genetic convergence is a major factor, its scale and scope is uncertain - occurring at a specific site, within a particular gene, along a pathway or in a genetic network. In our study, we analyzed transcriptome data of 83 samples across 57 Pedicularis species to build a phylogenetic tree using both coalescent-based and concatenated-based methods. We reconstructed ancestral colors in internal nodes using different MK-based models. We investigated gene tree-species tree discordances and the prevalence of hemiplasy in floral color evolution. By applying diverse phylogenetic comparative methods, we aim to detect potential evolutionary and genetic mechanisms underlying floral color evolution. This study will contribute to our understanding of the evolution and function of convergent floral phenotypes.