Phenotype of DgPAPS4 transgenic plants, and the expression levels of genes involved in the vernalization pathway. A, Morphological phenotypes of DgPAPS4 transgenic plants and Col-0 wild-type plants after 4 weeks vernalization treatment and then 21 d growth under long-day conditions. “WT” indicates the wild type (Col-0), and “OE” indicates the transgenic line. Scale bar, 2 cm. B, Flowering time of DgPAPS4 transgenic plants and Col-0 wild-type grown under long-day conditions after vernalization (Data are means ± SD, n = 10, Wilcoxon test, **P<0.01). C, Expression of AtAGL20 with different vernalization treatments in transgenic and wild-type plants; NV, non-vernalization; V4W, vernalization treatment for 4 weeks. Error bars indicate the standard error of three biological replicates (Wilcoxon test, **P<0.01). D, DNA methylation levels of promoter regions of AtAGL20. McrBC-qPCR analysis was performed in WT and transgenic plants after vernalization. Methylated DNA can be digested by McrBC, thus higher qPCR signals indicate lower methylation levels. Error bars indicate the standard error of three biological replicates (Wilcoxon test, *P<0.05; **P<0.01).