Phylogenetic Analyses of Some Key Genes Provide Information on Pollinator Attraction in Solanaceae

Floral syndromes are known by the conserved morphological traits in flowers associated with pollinator attraction, such as corolla shape and color, aroma emission and composition, and rewards, especially the nectar volume and sugar concentration. Here, we employed a phylogenetic approach to investigate sequences of genes enrolled in the biosynthetic pathways responsible for some phenotypes that are attractive to pollinators in Solanaceae genomes. We included genes involved in visible color, UV-light response, scent emission, and nectar production to test the hypothesis that these essential genes have evolved by convergence under pollinator selection. Our results refuted this hypothesis as all four studied genes recovered the species' phylogenetic relationships, even though some sites were positively selected. We found differences in protein motifs among genera in Solanaceae that were not necessarily associated with the same floral syndrome. Although it has had a crucial role in plant diversification, the plant-pollinator interaction is complex and still needs further investigation, with genes evolving not only under the influence of pollinators, but by the sum of several evolutionary forces along the speciation process in Solanaceae.