Changes in FLC and VIN3 Expression during Vernalization of Arabidopsis thaliana Plants from Northern Natural Populations

Specific expression patterns of the FLC and VIN3 genes, which play a key role in the vernalization-mediated transition to flowering of A. thaliana plants from northern natural populations (Karelia), have been revealed. The differences in the FLC and VIN3 expression patterns during vernalization for populations represented by late-flowering forms, on one hand, and a population which was mixed with respect to the onset of flowering, on the other hand, were observed. A low level of FLC and VIN3 expression in plants from the studied populations prior to cold exposure was established. During vernalization, the FLC mRNA levels increased on the 10th and 20th day, followed by its decrease by the 30th day. Prolonged exposure to cold caused an increase in VIN3 expression with a peak in the populations represented by late-flowering plant forms on the 30th day of vernalization and in the mixed population for the flowering onset of plants on the 40th day. Specific patterns of FLC and VIN3 expression during vernalization was observed in S1 offspring of one early-flowering plant, while FLC expression in it changed according to classical scheme; i.e., the initially high level of FLC expression decreased in the process of vernalization. It is suggested that genetic and epigenetic mechanisms involved in controlling the flowering rate and the genes involved in this process may differ in plants from populations of different geographic regions.