Phytobilin biosynthesis: the Synechocystis sp. PCC 6803 heme oxygenase-encoding ho1 gene complements a phytochrome-deficient Arabidopsis thaliana hy1 mutant

摘要: The phytobilin chromophores of phycobiliproteins and phytochromes are biosynthesized from heme in a pathway that begins with the opening tetrapyrrole macrocycle protoheme to form biliverdin IXα, reaction catalyzed by oxygenase. An Arabidopsis thaliana hy1 mutant was previously shown be deficient phytochrome responses, these responses were regained when plants administered IXα. A oxygenase-encoding gene, ho1, recently cloned cyanobacterium Synechocystis sp. PCC 6803. When ho1 expressed Escherichia coli, cells produced active ferredoxin-dependent soluble open reading frame fused chloroplast transit peptide-encoding sequence oli gene Antirrhinum majus. This construct placed binary plasmid vector containing kanamycin resistance marker cauliflower mosaic virus 35S promoter control expression chimeric oli-ho1 used transform A. plants. Two independent transformed lines obtained had phenotype parental Landsberg erecta line as indicated detection its mRNA reverse transcriptase-polymerase chain reaction. results indicate 6803 oxygenase encoded can substitute for defective HY1 product only required enzyme activity is