|Gong, Ping - UNIVERSITY OF ILLINOIS|
|Wu, Guosheng - UNIVERSITY OF ILLINOIS|
Submitted to: Plant Biology
Publication Type: Abstract Only
Publication Acceptance Date: February 21, 2004
Publication Date: August 1, 2004
Citation: Gong, P., Wu, G., Ort, D.R. 2004. Cloning of A Chloroplast Atp Synthase Activation Mutation In Arabidopsis [abstract]. Plant Biology. Available: http://abstracts.aspb.org/pb2004/public/P39/7963.html. Technical Abstract: In plants, the chloroplast ATP synthase functions to synthesize ATP from ADP and phosphate driven by the proton motive across the thylakoid membrane. The ATP synthase maintains high synthetic activity in the light and assumes a latent inactive state to avoid futile hydrolysis of ATP in the dark. Previously we isolated an EMS-mutagenized Arabidopsis mutant, denoted coupling factor slow recovery (cfs) mutant, which showed anomalous ATP synthase activation/deactivation characteristics as well as a distinct growth phenotype compared to the wild type. The most significant feature of this mutant is that the deactivation of ATP synthase induced by dark adaptation is very slow, indicating interference with the ATP synthase regulatory system. Genetic analysis showed that the cfs mutant is a recessive allele and the trait is controlled by a single nuclear gene. In order to identify the cfs gene, we did genetic and positional mapping with SSLP and CAPS markers. The cfs gene was mapped to a region in the bacterial artificial chromosome (BAC) clone T16L24 and F24G16. This portion of the chromosome turned out to be a region of extremely low recombination preventing finer mapping. We obtained Agrobacterium transferred DNA (T-DNA) insertion mutants from the Salk Institute Genome Analysis Laboratory (SIGnAL) for each of the 34 putative genes located in this region and screened the phenotypes. Only one homozygous T-DNA mutant gene knockout line showed a similar phenotype to cfs. We cloned and sequenced this gene and confirmed the EMS mutation site. The cfs mutant arises from a point mutation of G to A producing an amino acid substitution from Trp to Stop, thereby producing a truncated protein. The further investigation of cfs gene and the function of its gene product are in progress.