基于SSR和InDel标记的大翼橙亚属种质遗传多样性及群体结构分析

Genetic Diversity and Population Structure Analysis of Papeda Germplasms Using SSR and InDel Markers

元江宜昌橙是在云南元江县新发现的宜昌橙(Citrus ichangensis Swingle)原始野生资源。为了解元江宜昌橙与长江流域宜昌橙的遗传差异,以及元江宜昌橙野生种群内个体间的遗传差异,利用筛选的21对SSR和InDel引物对元江宜昌橙群体、长江流域宜昌橙群体、大翼橙群体、香橙(C.junos Siebold ex Tanaka)群体等4个群体的48份资源进行了遗传多样性分析。结果表明,21对引物共产生了131条多态性条带,平均每对引物检测到6.2个多态性条带,多态性标记位点的香农信息指数为0.14~1.11,平均期望杂合度为0.04~0.97。群体遗传结构分析、UPGMA聚类分析和主坐标分析均表明,元江宜昌橙是不同于长江流域宜昌橙的新类型,4个群体间的遗传差异较大,群体间的基因流较低。在元江宜昌橙种群内存在遗传异质个体,但种群内的遗传多样性水平比长江流域宜昌橙群体的遗传多样性水平低,香橙群体的遗传多样性水平较高。大翼橙群体中的马来西亚大翼橙(C.macroptera Montrouz.)与宜昌橙遗传距离较远,而红河大翼橙(C.hongheensis Y. L. D. L.)与元江宜昌橙的遗传距离较近。野生的元江宜昌橙是有别于长江流域宜昌橙的新类型,在进行元江宜昌橙野生资源的收集时,以居群为单位更有利于保护其遗传多样性。

Yuan Jiang ichang papeda(Citrus ichangensis Swingle) is a kind of wild ichang papeda recently discovered in Yuan Jiang county, Yunnan province. To learn the genetic diversity of papeda populations, 48 papeda germplasms from Yuan Jiang and other origins in four populations namely as Yuan Jiang ichang papeda, Yangtze River ichang papeda, Honghe papeda(C. hongheensis Y. L. D. L.)and Xiang Cheng(C. junos Siebold. ex Tanaka)were examined with 21 pairs of SSR and InDel primers. A total of 131 polymorphic bands were obtained from 21 primer pairs, in average 6.2 polymorphic bands per pair primer. The Shannon information index of the polymorphic sites were 0.14~1.11, and average expected heterozygosity were 0.04~0.97. Population genetic structure analysis, UPGMA cluster analysis and principal component analysis all showed that Yuan Jiang ichang papeda is a new type of papeda different from the ones found in Yangtze River Basin. The genetic variance among populations were tested and the gene flow among populations were relatively low. Although genetic heterogeneous individuals were found in Yuan Jiang ichang papeda population, the genetic diversity within Yuan Jiang ichang papeda population was lower than that of in Yangtze river ichang papeda, and Xiang Cheng population which had the highest genetic diversity. Malaysian papeda is obviously divergent from ichang papeda, while the genetic distance between Honghe papeda and Yuan Jiang ichang papeda is close. This study indicated that Yuan Jiang ichang papeda was a new type of papeda divergent from the one originated in Yangtze River Basin. Collecting individual population of Yuan Jiang ichang papeda is important for preserving the genetic diversity of this endangered species.