石榴种质资源的matK基因序列分析

Sequence Analysis on matK Gene from Pomegranate(Punica granatum)Germplasm Resources

本研究以60个石榴品种为材料,PCR扩增获得石榴品种的matK基因片段,分析石榴资源的matK基因序列的碱基组成、序列间碱基变异频率和转换/颠换比率;计算品种间遗传距离(K-2P),构建遗传关系分类图,研究matK基因序列对石榴品种鉴定的效果。结果表明,石榴物种的matK基因片段容易获得,PCR扩增成功率为98.3%,测序成功率为100%,59个石榴品种matK基因片段最长为897 bp,最短为820 bp。石榴的matK序列保守性为95.8%,G+C含量相对稳定,平均含量为33.3%,A+T平均含量高达66.7%,密码子偏好A和T;序列碱基存在转换/颠换比率为1.003,核苷酸多样性为0.000 8,每位点核苷酸多态性指数Theta值为0.000 54。K-2P遗传距离在0.000~0.024之间,平均遗传距离为0.007,邻接法(NJ)构建59个品种遗传关系聚类图,59个品种被分为6大类,分类结果与形态学和品种地理来源分类没有明显相关性。

60 pomegranate cultivars were used as the experimental materials in this research.The matK gene fragment was obtained by PCR method.The base composition,base variation frequency and transform/transversion frequency of matK gene sequence were analyzed.The genetic relationship tree was constructed by genetic distance(K-2P).The effectiveness on the identification and the genetic relationship analysis of pomegranate cultivars based on the matK gene was studied.The results showed that the matK gene fragment was obtained easily with the 98.3%PCR amplification frequency and 100%sequencing frequency.The gene fragment length ranged from 820~897 bp.The base conservative rate was 95.8%among matK gene sequences;the average G+C content was 33.3%,and the G+C content was relatively stable.The favorite genetic code was A+T with average content 66.7%;the transform/transversion frequency was 1.003.The nucleotide diversity was 0.0008,and the Theta value of the nucleotide polymorphism index per site was 0.00054.The genetic distance(K-2P)ranged from 0.000~0.024 and the average genetic distance was 0.007.The genetic relationship tree was constructed by NJ method according to K-2P.59 cultivars were divided into 3 groups.The cluster result based on matK gene sequence was not accorded with the classification results based on morphology method and geographical origin.