Cloning and allelic variation of two novel catalase genes (SoCAT-1 and SsCAT-1) in Saccharum officinarum L. and Saccharum spontaneum L.

Catalases (CAT) play important roles in plant defence mechanisms, stress response, cellular redox balance and aging delay. In order to clone CAT genes in cultivated (Saccharum officinarum L.) and wild (S. spontaneum L.) sugarcane, we designed two pairs of specific primers using a full length cDNA sequence of sorghum CAT gene (XM 002437586.1) as the probe. Two novel full-length sequences of CAT genes (SoCAT-1 in S. officinarum and SsCAT-1 in S. spontaneum) were cloned by nested polymerase chain reaction. Two allelic variants were found at SoCAT-1 (SoCAT-1a and SoCAT-1b, GenBank accession nos. KF864224-25) and SsCAT-1 (SsCAT-1a and SsCAT-1b, GenBank accession nos. KF864226-27) loci. The full lengths of SoCAT-1a, SoCAT-1b, SsCAT-1a and SsCAT-1b were 3816 bp, 3814 bp, 3777 bp and 3812 bp, respectively, and all contained eight exons and seven introns, with a similar gene structure. The length of cDNA for all four genes was 1532 bp, containing 10 bp 5'-untranslated region (UTR) and 43 bp 3'-UTR, and an open reading frame of 1479 bp encoding a polypeptide of 492 amino acids. High homology of DNA (99.0% for SoCAT-1, 98.2% for SsCAT-1) and cDNA (99.3% for SoCAT-1, 99.4% for SsCAT-1) were found. Eleven single nucleotide polymorphisms were found in cDNA SoCAT-1 and nine ones in SsCAT-1, and nine and five amino-acid mutation sites in the predicted proteins, respectively. The predicted proteins encoded by SoCAT-1 and SsCAT-1 showed high homology with CAT in sorghum, rice, corn and other species.