Comparison of Promoter Sequences of Flowering Control Genes, FT1 and Three Versions of VIN3, in Susceptible and Resistant Sugar Beet Genotypes to Bolting

Autumn sowing of sugar beet is a suitable way in sustainable agriculture. Bolting is an undesirable phenomenon which reduces sugar beet yield and it is the most important limiting factor in autumn sowing of sugar beet. Identification and comparison of the sequence of flowering genes in various genotypes can help to understand the molecular mechanisms controlling bolting. In the previous studies, it was revealed that expression level of FT1 and VIN3 genes in sugar beet is associated with bolting resistance. In this study, the sequence of FT1 gene promotor and three versions of VIN3 gene promoters of sugar beet were compared in three bolting resistant and three bolting susceptible genotypes. Primer design for each gene was carried out using the DNA sequences found at the NCBI database. DNA was extracted from leaf samples growing in pots and was used as template in PCR reactions. Similar length of amplified fragments for each promoter gene in bolting susceptible and bolting resistant genotypes were selected and sequenced for more accurate assessment. There was no mutation in the FT1 gene promoter, however 624 substitution and insertion/deletion mutations were observed in the promoter of three versions of VIN3 gene. A 228-bp ins/del region was detected in the VIN3-like1 promoter. This region contains promoter elements and seems to have a control function. Comparison of detected mutations between susceptible and resistant genotypes did not show a distinct pattern for bolting.