烟草PMT基因单核苷酸多态性与烟碱含量变异的研究

Study on the Single Nucleotide Polymorphism of PMT Gene and the Variation of Nicotine Content in Tobacco

为了解析不同烟草品种间烟碱含量差异的遗传机制,深入探索烟碱表型变异与基因序列多样性之间的关系。本研究从29份烤烟品种全基因组重测序所揭示的基因组序列变异中,分析了普通烟草种4个PMT基因家族基因的SNP和Indel变异,筛选错义突变位点。发现在NtPMT2基因第1个外显子的第75个碱基处存在1个错义SNP位点C23_49502707,在供试群体存在G和T两种等位变异。结合8个环境点的烟碱表型鉴定,可知在显著水平上T基因型等位变异供试品种的烟碱平均含量比G基因型的高14.7%,是高烟碱优异等位变异。进而对该位点进行了PCR标记转化,并筛选到1对扩增稳定、带型清晰的功能标记。本研究为克隆烟碱含量调控相关基因奠定了良好的实验基础,为高烟碱品种的分子标记辅助选择提供了可用的标记和基因资源。

In order to an alyze the genetic mechanism of nicotine content and explore the relationship between genetic diversity and phenotypic variation of nicotine. Whole genome resequencing of 29 tobacco varieties was developed. Also, missense mutation loci screening, SNP and Indel analysis of 4 PMT genes, which were the key rate-limiting enzyme during nicotine biosynthesis has been carried out. We found that of the 4 genes, there are 1missense SNP locus C23_49502707 in the 75 th bases of the first exons in NtPMT2. And there were 2 allelic variations of G and T in the tested group. Nicotine phenotype identification in 8 different environments showed that the nicotine content of T genotype was 14.7% higher significantly than that of G genotype. It means that the T genotype was the favorable allele to the high nicotine content. Farther more, the site was transformed into PCR marker, provided a pair of clear and stable functional markers. This study laid a good foundation for the cloning of related genes in nicotine content regulation. And provides molecular marker resources and available gene for the breeding of high-nicotine tobacco varieties.