基于PAL基因序列的地方苦荞品种遗传多样性分析

苦荞在中国具有广泛的栽培种植地区,长时间演化形成了丰富的遗传多样性。为了研究和利用苦荞资源,以国内北方苦荞产区(内蒙古、青海、陕西、山西、甘肃)、西南苦荞产区(西藏、四川、贵州、云南)、国内其他地方品种(江西、安徽、湖北、湖南、广西)及国外品种(尼泊尔)共计67份苦荞材料为研究对象,PCR扩增其PAL基因并测序。在此基础上分析苦荞的遗传多样性,并采用NJ法(neighbor-joining)对67份苦荞材料构建系统进化树。结果表明,供试的67份苦荞材料的PAL基因序列长度为2011 bp,其中,变异位点为160个,占序列总长度的7.9%,简约信息位点为33个,占序列总长度的1.64%,突变的类型主要是碱基的转换与颠换,高变异位点均集中在外显子2的N端。不同来源的苦荞材料间的遗传距离分布于0.002~0.016之间,来源于中国四川组的苦荞材料种内平均遗传距离最大(0.016),中国内蒙古组的最小(0.002)。中国四川地区的材料与其他地区来源的材料间的遗传距离位于0.010~0.016之间,而其他地区间的遗传距离为0.004~0.013。67份苦荞材料的平均π值和θ值分别为0.0034和0.0143。其中,中国四川材料的π值为0.0148。基于PAL基因序列构建的NJ进化树中,67份苦荞材料分为7个类群,分类与地理来源无关。仅中国西藏来源的5份材料聚集为一类,说明PAL基因序列较为稳定,多数材料间变化差异较小。中国四川地区的苦荞材料具有丰富的遗传多样性,中国西藏地区的某一材料中有较多的SNP位点,推测中国西藏的部分材料可能存在突变的热点区,预示着PAL基因新的突变位点区域。

Genetic Diversity of Tartary Buckwheat Based on the Sequence Analysis of PAL

Tartary buckwheat is widely cultivated in different areas of China and gradually evolved into genetic diversity.In order to study and utilize the tartary buckwheat,the PAL gene differences of the tartary buckwheat were analyzed on 67 samples,which were collected from different provinces of China (including the north region and the southwest region)and the Nepal region.We amplified the PAL gene by PCR and then acquired the sequence results.Based on the sequences,genetic diversity was analyzed and cluster of analysis of 67 samples was also carried out by NJ method.The results showed that after aligning and splicing,the length the PAL sequence was 2011 bp in the matrix,the variable sites was 160,while the parsimony informative sites was 33,accounting for 7.9％ and 1.64％ of the total length,respectively.Variable type were mainly base transition and base transversions.Variable site mainly concentrated in the region of 600-1200,which was the site of the N-terminal of the exon-2.The intra-specific mean distance of the Sichuan group was 0.016,while the tartary buckwheat from Inner Mongolia group showed that the intra-specific mean distance was 0.002.And it revealed that there was a significant difference among the tartary buckwheat resources in genetics diversity from different geographic origins.We checked the 67 PAL sequences using software.And it showed that the average value of the Nucleotide polymorphism (r) and the average heterozygosity (θ) were 0.0034 and 0.0143,respectively.The Nucleotide polymorphism (π)value in samples from Sichuan was the highest(0.0148).From the phylogenetic tree,it indicated that the 67 samples from the different province could be clustered into seven categories.And the 5 sample in Tibet were clustered into another category.These results showed that the PAL sequences of the majority tartary buckwheat samples was stable and the differences between the most samples was not significant.The samples in Sichuan province had abundant genetic diversity.But only in samples from Tibet it revealed many SNPs site,and this should be the new mutation spots in the PAL coding regions.