Characterization of spatial and temporal expression patterns and analysis of knock-out and overexpression lines of Arabidopsis P4H9 [Thesis (M.Sc.)]

four of them carry a single copy of the T-DNA insertion, another four carry a double copy of the T-DNA insertion and the last line has four copies. Only three lines were subjected to phenotypic analysis. In addition, to monitor promoter activity of the AtP4H9 gene during plant growth and development, five independent lines carrying a transcriptional fusion between the P4H9 promoter, GFP and GUS genes were identified. Seeds obtained from confirmed transformed plants showed that P4H9 is consistently expressed in the hypocotyl in all the lines in the three-day-old seedling stage. The obtained data indicate an important role of AtP4H9 in plant growth and development in Arabidopsis.

anglais. Prolyl 4-hydroxylases catalyze the formation of 4-hydroxyproline in collagens and other proteins found in animals, plants, microbes and viruses. The genome of Arabidopsis thaliana encodes thirteen P4H genes. However, only AtP4H1 and AtP4H2 were characterized while not much is known about the rest of the genes. Previous data from our laboratory indicated that P4H9 is involved in ethylene regulation of cell elongation. We report here on the phenotypic characterization of a p4h9-1 T-DNA insertional mutant and three independent lines overexpressing P4H9, compared to the wild type, under different conditions: three days under dark and ten days under light. Homozygous p4h9-1 T-DNA insertional mutants were screened and selected by PCR, as well as over-expressing 35s::P4H9 plants, were selected and screened for the presence of the construct. Nine independent lines were subjected to copy number identification