LiT:HRB1 and PP7 in de-etiolation and Stomatal Opening

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Intellectual merit. Red and blue light regulate seedling de-etiolation and stomatal aperture in natural environments. The signal transduction cascades that link the perception of light to the de-etiolation and stomatal opening responses are still largely unknown, and hypersensitive to red and blue (hrb) mutants are of particular interest. The hrb mutants were initially isolated for their short hypocotyl phenotype under red and blue light. The hrb mutants are also more resistant to dehydration and show reduced water loss and blue light-regulated stomatal aperture. The HRB1 gene has been cloned and the hrb2 and hrb3 mutations have been mapped to chromosomes 2 and 4, respectively. HRB1 is a nuclear ZZ-type zinc finger protein and physically interacts with phosphatase 7 or PP7, a previously identified positive regulator of blue light signaling in the nucleus. HRB1 is phosphorylated in vivo and is involved in a protein complex mostly in its de-phosphorylated form. The goal of this project is to study the function of HRB1 and PP7 and their interaction in the control of de-etiolation and stomatal aperture under blue light. The studies on these genetic and biochemical interactions will bring novel insights into HRB1 function and the network structure of the light signaling machinery. Broader impacts. This research will provide opportunities for undergraduates, graduate students, and postdoctoral fellows to gain significant research experiences and to develop their ability to critically analyze and solve scientific problems. A diverse group of undergraduates will include African Americans and Hispanics drawn from academic courses and from a campus-wide life science summer undergraduate research program. A specific training plan has been designed for the undergraduates, ranging from physiological, genetic, to molecular studies. This project will also support undergraduate education through seminars at small and research-limited undergraduate institutions and recruitment of students at these institutions to perform summer research at the University of Minnesota. On an even broader level, the proposed studies will open new possibilities to engineer plants to survive desiccation by controlling stomatal function and hence CO2 uptake and the loss of water through transpiration.