Intraspecific polymorphism in peroxidase genes located on Arabidopsis thaliana chromosome 5

Nucleotide sequences of five peroxidase genes AtPrx52-AtPrx56 located on the upper arm of chromosome 5 were comparatively analyzed for six Arabidopsis thaliana ecotypes and lines (Columbia, Dijon-M, Blanes-M, Enkheim-M, Ler, and K-156). The level of intraspecific nucleotide variation significantly differed between these genes (up to 20 times): the greatest diversity was observed in the tandemly duplicated AtPrx53 and AtPrx54 genes, while the least variation was observed in AtPrx56 gene. AtPrx53 and AtPrx54 genes demonstrated allelic dimorphism and nonrandom association of polymorphic sites was demonstrated for AtPrx54 gene. A relationship has been revealed between haplotypes of these genes and the mobility of anionic peroxidase isoforms. Since the haplotypes of AtPrx53 gene code for proteins with two nonconservative amino acid substitutions, different mobility of anionic peroxidase isoforms could be due to diallelic polymorphism in the amino acid sequence of AtPrx53 protein.