Mark Estelle, IOS-0744800, Auxin Signaling in the Early Diverged Land Plant Physcomitrella patens.
Many aspects of plant growth and development are regulated by a hormone called auxin. Traits such as plant stature, flower development, and fruit and seed development are influenced by auxin. The hormone regulates these processes by influencing plant cell division and expansion. During the last decade there have been several important advances in our understanding of auxin signaling. However, there are still many unanswered questions. In particular there is little information on how auxin affects cell growth. In addition, the role of auxin in key events during plant evolution is largely unknown. To address these questions, studies of the moss Physcomitrella patens will be conducted. Because growth and development of the mosses is relatively simple compared to flowering plants their study offers some important advantages. In addition, the mosses are some of the earliest land plants to appear on earth. Therefore understanding how auxin works in P. patens will contribute to knowledge of the role of auxin during plant evolution.
To achieve these goals, moss genes involved in auxin signaling will be identified based on their similarity to known genes in flowering plants. Moss plants with mutations in these genes will be generated and the effects of the mutations on growth will be analyzed. The biochemical characteristics of auxin receptors from moss will be determined. This information will help to establish fundamental rules for auxin receptor function.
The proposed project will have broader impact in several areas such as the training of postdoctoral fellows and undergraduate students, participation of initiatives for maximizing student diversity, and involvement with outreach programs to local communities.
The plant hormone auxin is an essential regulator of most aspects of plant growth including processes of agricultural importance such as plant stature, seed and fruit development, and response to stresses such as drought and high temperature. Understanding how auxin regulates growth will allow us to develop new crop varieties that are adapted to changing environmental conditions. Although there has been recent progress in our understanding of auxin action, there are still many unanswered questions. The goal of our project is to understand how auxin functions in the simple plant Physcomitrella patens, a moss. The genome sequence of P. patens was recently determined and this allowed us to identify genes that may function in auxin signaling. We showed that auxin works in a very similar way in moss as in the flowering plants we use in agriculture. Because moss and related plants were the first to colonize land about 500 million years ago, our results indicate that the mechanism of auxin signaling is similar (or conserved) in all land plants. This is a powerful discovery because it means that knowledge we gain using the simple moss plant will be relevant to more complex and difficult to study crop species. Our future studies promise to provide new information on how auxin regulates plant cell growth in all plants.
