MTHFD1 controls DNA methylation in Arabidopsis

In order to further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. We identified the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me, and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. 2 BS-seq datasets for genome-wide analysis of differential DNA methylation, 18 BS-seq datasets for global DNA-methylation analysis, and 3 RNA-seq datasets for differential gene expression analysis.