Abstract
Flowering state lasts long in Perilla frutescens var. crispa, a short-day plant. This reminds us of vernalization where the low temperature effect lasts long suggesting the existence of a common mechanism between them.
DNA methylation/demethylation is involved in the regulation of vernalization. Accordingly, we treated Perilla with 5-azacytidine in long-day condition. The treatment caused flowering.
It is known that rDNA intergenic spacer region is methylated. Accordingly, the genomic DNAs were isolated from leaves of the 5-azacytidine-treated and untreated Perilla, digested with a restriction enzyme, Msp I (methylation-insensitive) or Hpa II (methylation-sensitive), and then Southern hybridization analysis was performed with 25S-18S rDNA intergenic spacer region as a probe. The ladder signals shifted to lower molecular weight region in the treated plants, indicating that the 5-azacytidine treatment caused demethylation of the genomic DNA. The result suggests that DNA demethylation is involved in the flowering of Perilla.
