Cloning of SOD Gene Segments and SNP Analysis in Citrus

[Objective] The study aimed to accurately analyze the genetic diversity of citrus.[Method] A pair of degenergte primers was designed according to the 2 conserve regions on the amino acid sequence of Mn/Fe-SOD gene from many kinds of plants that reported in Genebank.The Mn/Fe-SOD gene segments with length of 426 bp were cloned by using RT-PCR technology in 6 kinds of citrus like Citrus maxima cv.Lingnanshatianyou and Citrus limon and their sequences were made for SNP analysis.[Result] The nucleotide similarity in citrus was as highest as 97.2% at 6 gene segments each other and that with the sequence of Mn/Fe-SOD gene from other plants was above 77.7%.Every nucleotide sequence encode 142 amino acids according to the derivation of the amino acid sequence and the similarity was 97.9% at 6 gene sequences each other and that with the amino acid sequence of Mn/Fe-SOD gene from other plants was above 79.0%.In the Mn/Fe-SOD gene segments there were 18 variation sites of nucleotides that had SNPs,which caused that 3 amino acid sites occured the variation.The polymorphism frequency was 1SNP/23.7 bp and the degree of variation of nucleotide and amino acids were 4.23% and 2.38% resp.[Conclusion] The study laid the foundation for richening the construction of genome markers and the plant genetic markers of resistance character in citrus.