Photosynthetic organisms optimize utilization of light in different environments. Little is known about the protective mechanisms by which these organisms cope with excess absorption of light energy under high intensity light. Understanding these mechanisms will help in developing crops that are able to thrive even under harsh environmental conditions. The project focuses on regulation and function of four high light inducible polypeptides (HLIP) and using them as research tools to study the molecular mechanisms of cell survival under high intensity light in Synecocystis sp. PCC 6803. First, the regulators that control the expression of hli genes (encoding HLIPs) will be sought by screening for mutants defective in hli regulation using genetically engineered strains that carry sacB or gusA coding sequences under the control of hli promoters. Secondly, the functions of HLIPs in cell survival under high intensity light will be determined by mutant studies, and by screening for suppressors that restore the viability to a quadruple hli deletion mutant that dies in high light. Thirdly, the HLIP complexes will be determined by combining means of bio-separation, mass spectrometry, protein cross-linking and mutant dissection. These studies will contribute significantly to the understanding of the molecular mechanisms of high light acclimation in photosynthetic organisms. HLIPs are preserved in higher plants including crops and they are considered as potential stress reducers; therefore, the research will generate important leads for potential application of HLIPs to enhance crop production.
Broader impacts: The project is designed to actively involve undergraduate and graduate students from underrepresented groups (mainly African-American) to make significant contributions to the understanding of the mechanisms of photoprotection. Part of their training will include writing papers and making presentations at scientific meetings at which the results of the studies will be disseminated. This project also include participation in an existing program (Teaching Enhancement Affect Minority Students at the University of Arkansas at Little Rock) that focuses on increasing the enrollment and retention of minority students and helping them to enter graduate and professional schools. In addition, laboratory-based courses will be created. These courses will provide students with opportunities for critical thinking and scientific discovery, and help students to gain research experience and parlay it into a job in either biotechnology or education.
