应用IMP标记分析30份烟草品种的遗传关系

MITE (miniature inverted repeat transposable element)是植物中存在的高重复的一类转座元件。基于邻近MITE扩增多态设计的分子标记称为IMP标记(inter MITE polymorphisms)。从133个IMP引物中筛选出32个稳定多态的引物, 并以30个烟草品种为材料, 获得185个多态条带, 平均每对引物检测多态条带5.78个。聚类分析显示, 参试品种间遗传距离的变化范围为0.02~0.81、平均为0.33。30份烟草品种可分为3类, 晒烟、香料烟、北方烤烟品种等属I类; 第II类主要是美国NC系列品种、Coker系列品种和云烟系列烤烟品种; 第III类为两个白肋烟品种。结果表明, IMP标记能够在烟草中扩增并获得品种间多态信息, 可用于品种间的遗传关系分析, 这为烟草的遗传研究及分子辅助育种奠定基础。同时, 聚类结果显示, 30个栽培烟草品种之间亲缘关系较近, 丰富烟草种质资源应是今后育种的方向之一。

Genetic Diversity of 30 Tobacco Varieties Analyzed by IMP Markers

Miniature Inverted repeat Transposable Element (MITEs) is a high copy number transposon family in plants. Molecular markers based on closely located MITEs are termed Inter MITE polymorphisms or IMP. We conducted the genetic distance evaluation and cluster analyses of 30 tobacco cultivars using IMP markers. Among 133 primers screened, 32 primers had steady polymorphism bands. A total of 185 polymorphic bands were detected out of 30 cultivars, with 5.78 polymorphism bands per IMP primer. The genetic distance among cultivars ranged from 0.02 to 0.81, with an average of 0.33. According to cluster analyses, 30 tobacco cultivars could be classified into three groups. Group I included sun-cured tobacco, oriental tobacco and flue-cured tobacco of northern China; group II included USA NC series, Coker series and China Yunyan series; group III included two burley tobacco cultivars. The cluster analysis result closely matched the classic relationship among the cultivars. The result showed that the IMP markers, successfully amplified in tobacco, generated fairly polymorphism and could be applied in genetic diversity analysis. Thus, IMP markers establish a foundation for Tobacco genetic study and marker-assisted selection. The genetic diversity is very low among 30 tobacco cultivars investigated in this study, indicating that a strategy to enrich tobacco germplasm for further breeding should be developed.