The Ramírez Lab

University of California - Davis

Genetic Mechanisms of Floral Isolation in Orchids

Our previous work showed that euglossine-pollinated orchids exhibit remarkable modes of floral isolation that can be divided into two (non-mutually exclusive) mechanisms. One is the position of the pollinia on the bees, and the other is the production of unique fragrance compounds that attract species-specific assemblages of bee pollinators.

The Neotropical orchid genus Gongora is exclusively pollinated by fragrance-collecting euglossine bees. All the species in this orchid genus attach the pollinium onto the same body part of the bees (meso-scutellum), and thus their main mode of partitioning pollinators (and maintaining reproductive isolation in sympatry) is regulated by the chemical composition of the floral scent.

We are studying the evolution of fragrance production in the euglossine-pollinated genus Gongora. In this project we aim to combine a variety of methods to elucidate the evolution of scent production and the underlying genetic mechanisms that enabled rapid chemical differentiation in response to strong selection imposed by the chemical preferences of euglossine bees. For this project we are currently developing a variety of functional molecular assays (e.g. heterlogous expression), genomic tools (e.g. transcriptomes of several species), GC-MS measurements of scent composition, and population genetic analyses of target genes (e.g. Terpene Synthase genes).

More details soon.