Dissertation Research - Phylogeny and Trichome Evolution in the Brassicaceae

University Of Missouri-Saint Louis, Saint Louis MO

Investigators

Abstract

Phylogeny and trichome evolution in the family Brassicaceae This project focuses on determining relationships between plants in the mustard family and the use of this information in determining how the development of epidermal hairs on plants occurs. The mustard family (Brassicaceae) is of interest agronomically because it contains the Brassica species, whose variants include the crops broccoli, kohlrabi, kale, brussels sprouts, cabbage and cauliflower (among others). Canola oil is produced from the seeds of Brassica napus, and oils from the family are used in cooking as well as for industrial purposes. Brassicaceae is also an important plant family from a scientific perspective, due to the inclusion in the family of the plant genetic model species Arabidopsis thaliana, whose entire genome has been sequenced. The work builds collaboration between three research institutions in the St. Louis metropolitan area: University of Missouri St. Louis, Missouri Botanical Garden, Donald Danforth Plant Science Center. Despite the importance of the Brassicaceae, our understanding of the relationships of different Brassicaceae species to one another has lagged. Here, a detailed framework of the relationships of species within the family will be produced. And, genetic information obtained from published studies of Arabidopsis thaliana will be applied to other closely related species to help determine gene function. While studying genes in the context of model organisms gives insight into how particular genes function within the context of that organism, such studies cannot determine the likelihood that the genes in question evolved for that particular function, or if the genes play the same or similar roles in other plants. This question is addressed in this study by using the relationships determined within the plant family Brassicaceae in conjunction with genes known to affect the shape and size of epidermal hairs found on the leaves of many Brassicaceae species. The developmental progression associated with epidermal hairs in Arabidopsis will be compared with the development of hairs on closely related species of Brassicaceae to determine how development differs between them. This inquiry permits future studies to narrow the number of potential genes affecting differences in hair shape to only those active during developmental stages that differ between species. Furthermore, it provides valuable information about the cellular mechanisms that control cell shape, an important aspect of cellular development.