XVI International Botanical Congess

We have transformed Arabidopsis with an antisense construct of METI, a gene encoding a DNA methylase. Plants with reduced methylation showed changes in morphology and flower early.Some METI antisense plants have flowers that resemble a SUPERMAN mutants. This phenotype was associated with loss of methylation in sites flanking the locus, and with hypermethylation around the start of transcription and in the coding region. Early flowering of antisense plants was observed only for those plants that flower early in response vernalization, a cold treatment that promotes flowering, and can be mimicked by treatment with 5-azaC. The early flowering phenotype in the antisense plants is probably associated with demethylation of sequences that are important for the initiation of flowering.