茶树多酚氧化酶基因的SNP分析

Identification of single nucleotide polymorphisms (SNPs) in polyphenol oxidase gene in tea plant(Camellia sinensis)

选取有代表性的40个茶树品种(系)为材料,先采用PCR-SSCP-银染检测技术,对供试材料的多酚氧化酶(PPO)基因进行SSCP分析,对PPO基因作初步基因分型;根据分型分析结果,对每一类型选择典型品种的PPO基因作进一步的DNA序列分析,用DNASTAR Program进行单核苷酸多态性(SNP)搜寻.结果表明,茶树PPO基因存在丰富的SNP,其类型包括:转换(AG,CT)、颠换(AT,GC,G→T,A→C)与杂合子(C/T,A/G,G/T,A/T,A/C,G/C).在发现的37个SNPs中,有13个SNPs发生在核酸内切酶酶切位点,有10个错义SNPs位点导致氨基酸的改变.在PPO基因的保守序列区,出现SNP的频率较低.

Based on the PCR-SSCP（single strand conformation polymorphism）-silver staining method, choosing 40 typical tea cultivars, analyzing the SSCP of PPO gene in all accessions, the authors attempt to group the mutation type of PPO gene roughly. Then, the typical accessions were chosen in terms of the results of PCR-SSCP analysis and the sequences of PPO gene in chosen accessions were sequenced, and the SNP （single nucleotide polymorphism） searched through sequence comparison by DNASTAR program. The results showed that SNP in different accessions was abundant, including transition （A←→G, C←→T）, transversion （A←→T, G←→C, G←→T, A←→C） and heterozygote （C/T, A/G, G/T, A/T, A/C, G/C）. A total of 37 SNPs were discovered, among which, 13 SNPs arose at restriction site of endonuclease and 10 non-synonymous SNPs altered the amino acid. In the conservative domain of PPO gene, the frequency of SNP was lower.