MITE转座子在不同甘蓝型油菜品种中的多态性研究

Polymorphism of MITE in Different Brassica napus L. Varieties

微型反向重复转座因子(MITE)在真核生物基因组中普遍存在,其活动能够在物种内形成丰富的多态性,在基因组进化和基因调控中均发挥重要作用。该研究利用286对不同MITE家族侧翼序列筛选的特异引物,对101个中国油菜、27个加拿大油菜和29个合成油菜品系(共157个品系)的基因组DNA进行多态性研究,以明确MITE家族的插入/缺失多态性以及在不同油菜品种之间插入的遗传多样性,进而探讨他们之间的亲缘关系。结果显示:(1)286对引物中筛选出60对条带清晰重复性高的多态性引物,多态性比例21.0%;其中Stowaway-like家族和Tourist-like家族特异引物的多态性比例分别为24.6%和20.0%。(2)PCR扩增结果显示,60对多态性引物对中国、加拿大、合成油菜品系的基因组DNA分别扩增出4 029、1 044、1 087条清晰可辨的条带。(3)UPGMA聚类显示,中国油菜品种间遗传相似系数在0.59~0.95,加拿大油菜品种间遗传相似系数在0.73~0.95;合成油菜品种间遗传相似系数值在0.64~0.93。研究表明,MITE在基因组中大量随机插入,形成种内丰富的多态性,利用MITE家族引物检测不同地区的油菜种质资源的多态性,可为油菜的育种找到许多尚未被开发的遗传变异。

Miniature inverted repeat transposable elements(MITEs)are prevalent in eukaryotic genomes.Activities of MITEs induce abundant polymorphisms in species.They are known to critically influence genome evolution and gene regulation.In this research,286 MITE family specific primers were developed for polymorphisms screening among 157 Brassica napus genotypes including 101 and 27 natural varieties collected from China and Canada,respectively and 29 synthesized lines.Polymorphisms produced from Insertion/deletion of MITEs were used to dissect genetic diversities and relationship between different B.napus lines.Results demonstrated that:(1)sixty pairs of primers displayed clear and repeatable polymorphism bands among genotypes,which occupied 21.0%of all developed primers;Polymorphic rate of primers developed from Stowaway-like and Tourist-like families are 24.6%and 20.0%,respectively.(2)These 60 polymorphic primers were selected to screen MITE induced polymorphisms among Chinese,Canadian B.napus genotypes and 29 synthesized B.napus lines.There are 4 029,1 044 and 1 087 distinguishable bands amplified,respectively.(3)UPGMA analysis showed that,the genetic similarities are 0.59-0.95,0.73-0.95 and 0.64-0.93 in the populations of Chinese semi-winter,Canadian spring B.napus genotypes and synthesized B.napus lines,respectively.Our results indicate abundant inter-species polymorphisms are created by thousands of MITEs copies randomly insertion in genome.By using MITE family primers to detect the polymorphism of B.napus germplasm resources in different regions,we can find those polymorphisms provide resource for molecular marker assisted breeding of B.napus.