|Ortiz, Guadalupe - U OF ILLINOIS, URBANA|
Submitted to: Plant Physiology Supplement
Publication Type: Proceedings
Publication Acceptance Date: June 15, 1995
Publication Date: N/A
Technical Abstract: As an approach to gain further insight into the mechanism of reduction and reoxidation of chloroplast coupling factor (CF1), we have selected F reduction mutants from M population of Arabidopsis thaliana. One mutant appears incapable of reducing coupling factor under low irradiance, as is indicated by the flash induced absorption change at 418 nm relaxation kinetics, in leaves (Gabrys' et al. 1994 Plant Physiol 104:769-776). The segregation analysis indicates an inheritance pattern based on a single gene with incomplete dominance of the wild allele. Incubating dark-adapted wild type leaves in 3mM DTT resulted in complete reduction of the chloroplast coupling factor. However, incubation of leaves from the mutant under the same conditions resulted in only marginal reduction. Furthermore, inducible ATPase activity in chloroplast from mutant plants is much lower than in wild type plants. Since the segregation analysis indicates a nuclear mutation and since Y-subunit contains the regulatory disulfides, it is likely that the mutation is located in the F-Y subunit. We are currently cloning and sequencing the y-subunit of the mutant plant to test this notion. This work was supported in part by the USDA NRI-CGP Grant No. 91-37100-6620.