INSERTIONAL POLYMORPHISMS OF MINIATURE INVERTED-REPEAT TRANSPOSABLE ELEMENTS (hAT-like MITEs) IN INTRONS OF SUGAR BEET.

Sugar beet (Beta vulgaris L.) is an economically important crop due to its high sucrose content in roots and it is the second most important crop after sugar cane for sugar production in the world. The European Union is the world’s largest producer of sugar beet 50% of world production, accounting for 22% of sugar. Sugar beet is an obligate cross-pollinated crop that belongs to the family Amaranthaceae, chromosome number 2n=2x=18. The genome content of sugar beet is 758Mb of which the repetitive sequence is around 458 Mb which accounts for 64%. Transposable elements are mainly classified into two classes they are class I (Retro elements) and class II (DNA elements). Non-autonomous, miniature inverted-repeat transposable elements (MITEs) belong to class II TEs. MITEs are the most abundant non-autonomous DNA group that belongs to class II DNA elements in the plant genome. A group of plant hAT MITEs belongs to the Ac/Tam3 family. MITEs act as one of the significant sources of variations that occur in sugar beet. MITE copies inserted within introns can be exploited as potential intron length polymorphism (ILP) markers. PCR can detect ILP markers with primers anchored in exon sequences flanking the target introns. ILP markers are unique owing to their gene specificity, co-dominance, convenience, reliability cost-efficiency. Here, we designed primers for Bvh-ILP (Beta vulgaris hAT-like) MITE insertion sites within introns along the sugar beet genome and validated them as candidate ILP markers to develop a set of markers for genotyping the sugar beet. The designed set of Bvh-ILP markers is an easily accessible molecular marker genotyping system based on TE insertion polymorphism.