Molecular Control of Vascular Meristem Initiation and Activity

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The plant vascular system plays essential roles in transporting water and nutrients to all growing organs. In addition, woody fibers of the vascular system provide mechanical support for plant upright growth. Xylary wood also forms the majority of plant biomass on earth and serves as feedstock for biofuel production. Therefore, the vascular system is important to plant growth and development and woody biomass production. Despite the importance of the vascular system, it is challenging to study vascular initiation because the vascular tissue is buried under layers of other cell types and inaccessible for direct microscopic observation. The vascular system is initiated from a region named the rib zone that is located below the plant growing tip. This research investigates how plants initiate vascular bundles and identifies genes that regulate vascular cell division using recently discovered genes and genetic methodologies. Outcomes of this research include a better understanding of vascular tissue formation and the regulation of cell proliferation in vascular tissues. This project integrates research and education by engaging under-represented undergraduate and high school students.The vascular system transports water and nutrients and has allowed plant species to successfully colonize various of terrestrial environments since they evolved 450 Million years ago. The vascular system initiates from the apical meristem rib zone and organizes as vascular bundles. Cambial cells from vascular bundles proliferate and then differentiate into phloem and xylem. Understanding the regulation of vascular meristem initiation and activity is of great interest to plant biology research. Further, xylary wood serves as a renewable feedstock for biofuel production. Despite the importance of vascular tissue, there is a knowledge gap in our understanding of the initiation and activity control of vascular meristem. This project builds on the identification of a novel C2H2 transcription factor High Vascular Activity (HVA) to dissect the regulatory mechanisms of vascular initiation and meristematic cell proliferation. The first aim is to investigate the molecular function of HVA in regulating vascular initiation using deep imaging approaches. The second aim is to elucidate the functional mechanism of HVA in modulating vascular meristem activity. The third aim is to determine the function of HVA in xylem cell differentiation using genetic, biochemical, and transgenic studies. Overall, this project will lay the ground for molecular dissection of vascular meristem initiation and cambial proliferation in the stem.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.