cDNA cloning and characterization of a cotton peptide methionine sulfoxide reductase (cMsrA)

A full-length cDNA clone with high homology with Brassica napus peptide methionine sulfoxide reductase (PMSR) gene ( BnPMSR ), which could reverse oxidation of methionine residues into MetSO in protein, was cloned by suppression subtraction hybridization and cDNA library screening from Gossypium barbadense . This gene (named as cMsrA ; Accession number: AY224208) had a total length of 1059 bp with an open reading frame of 765 bp, and encoded a predicted polypeptide of 255 amino acids with a molecular weight of 28.4 kDa. The cMsrA protein shared 68.6, 66.3 and 65.8% identity with those PMSR proteins isolated from B. napus , A. thaliana and L. sativa respectively. Expression patterns revealed that cMsrA was enriched later and weaker in resistant variety 7124 ( Gossypium barbadense ) than sensitive variety Ejing-1 ( G. hirsutum ) under salt treatment and pathogens attack. These results indicated that cMsrA played an important role in protecting the cells against oxidative damage during the pathogens and salt stress.