Stomata are valve-like epidermal structures that control gas exchange and water loss by plants. They must be spatially organized in order to maximize photosynthetic yield and water use efficiency. In the model plant Arabidopsis, the receptor-like protein TOO MANY MOUTHS (TMM) is a key component of the cell communication pathway that controls the number and distribution of stomata during leaf growth. Despite recent advances in understanding stomatal development in Arabidopsis, almost nothing is known about the molecular mechanisms that control the formation of these remarkably diverse, yet critically important, structures in other plants. To address this problem, this project will investigate the function of the highly conserved TMM signaling protein in select plant species of economic or evolutionary significance. Knowledge gained will contribute substantially towards understanding the evolution of stomatal patterning mechanisms in species that exhibit different strategies of leaf development from Arabidopsis. Specifically, this project will use a molecular approach to identify TMM-like genes from target plant species, examine evolutionary relationships among them, and investigate whether these genes function in stomatal development or instead have alternate activities. This work will provide specific information about the development of stomata in other plants that could ultimately lead to biotechnological improvement of food and fuel crops. It will also provide general insights into the evolution of cell communication pathways that regulate developmental processes. In the long term, it will serve as a foundation to guide future investigation of the emergence of stomata as a fundamental adaptation that allowed plants to colonize land. Undergraduate and graduate students from diverse backgrounds will be trained in cell, developmental and evolutionary biology through active recruitment from a student body rich in groups underrepresented in science. Finally, the breadth of the proposed research will foster interdisciplinary collaboration with researchers in bioinformatics, plant systematics, ecophysiology and climate change
