Format: ORAL

Mercedes Snchez-Cabrera1, Eduardo Narbona2, Montserrat Arista1, Pedro L. Ortiz1, Francisco J. Jimnez-Lpez3, Amelia Fuller4, Benjamin Carter5, and Justen B. Whittall4

1 Universidad de Sevilla, Seville, Spain 2 Universidad Pablo de Olavide, Seville, Spain 3 Universidad Rey Juan Carlos, Móstoles, Spain 4 Santa Clara University, Santa Clara, CA, USA 5 San Jose State University, Santa Jose, CA, USA

Polymorphisms are common in plant and animal species. However, the origin, maintenance and evolutionary forces acting on cases where the polymorphisms are shared between closely related species remains challenging. How is a shared polymorphism maintained across closely related species? Convergent evolution, introgression, and the maintenance of an ancestral polymorphism are the three main possible evolutionary pathways. Although shared neutral genomic variation is commonplace, very few examples of shared functional traits exist. Herein, we investigate a fascinating case that involves a blue-orange flower color polymorphism maintained across two closely related species, Lysimachia monelli and L. arvensis, using a multiscale approach. We performed UV-vis reflectance spectra, flavonoid biochemistry, and petal transcriptome comparisons followed by climate niche analysis, to explore different hypothetical evolutionary scenario of the polymorphism origin. The similarities in reflectance spectra, biochemistry, and transcriptomes suggest that a single shift from blue-to-orange shared by both species is possible. Transcriptomic analyses revealed two orange-specific genes are directly involved in both blue-orange color polymorphisms: DFR-2 specificity redirects flux from malvidin to pelargonidin production while BZ1-2 stabilizes it with glucose, producing the orange pelargonidin 3-glucoside. Interestingly, the different geographic distribution pattern between both species suggests that their environmental adaptations may transcend flower color variation and that both species experienced a different evolutionary history since their divergence, adding complexity to the maintenance of the polymorphisms to the present days. This persistent flower color polymorphism may represent an ancestrally polymorphic trait that has transcended speciation with some unique ecological effects.