Overview: About one-third of the ~275,000 angiosperm species (i.e., the Asteridae clade) produce flowers with fused petals forming a corolla tube. The various elaboration of the corolla tube (e.g., making it longer, wider, twisted) has enabled Asteridae plants to exploit many specialized pollinator groups (e.g., hawkmoths, hummingbirds, beeflies), which in turn drives the rapid diversification of floral forms. However, the developmental genetics of corolla tube formation and elaboration is little known, largely because the conventional plant genetic model system, Arabidopsis, does not have fused petals. In this project we use chemically induced mutants of M. lewisii (Figure 1) to elucidate the genetic network that regulates corolla tube formation and elaboration.
Future Perspectives: Once we have learned more about the genetic bases and developmental mechanisms that make the corolla tube longer or shorter, wider or narrower, straighter or more twisted, using the M. lewisii mutants, we will apply what we learned from M. lewsii to other Mimulus species (Figure 2) and other plant groups that have interesting natural variation in the corolla tube structure (e.g., Iochroma, Penstemon, Lonincera, Centropogon, Gilia). Perspective graduate students who are interested in taking an Evo-devo approach to understand the evolution of corolla tube variation in those other plant groups are encouraged to develop their dissertation projects in that direction.