DNA methylation is critical for Arabidopsis embryogenesis and seed viability.
DNA methylation (5-methylcytosine) in mammalian genomes predominantly occurs at CpG dinucleotides, is maintained by DNA methyltransferase1 (Dnmt1), and is essential for embryo viability. The plant genome also has 5-methylcytosine at CpG dinucleotides, which is maintained by METHYLTRANSFERASE1 (MET1), a homolog of Dnmt1. In addition, plants have DNA methylation at CpNpG and CpNpN sites, maintained, in part, by the CHROMOMETHYLASE3 (CMT3) DNA methyltransferase. Here, we show that Arabidopsis thaliana embryos with loss-of-function mutations in MET1 and CMT3 develop improperly, display altered planes and numbers of cell division, and have reduced viability. Genes that specify embryo cell identity are misexpressed, and auxin hormone gradients are not properly formed in abnormal met1 embryos. Thus, DNA methylation is critical for the regulation of plant embryogenesis and for seed viability.
Xiao
Wenyan
W
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
Custard
Kendra D
KD
Brown
Roy C
RC
Lemmon
Betty E
BE
Harada
John J
JJ
Goldberg
Robert B
RB
Fischer
Robert L
RL
D017360:Arabidopsis / Q000166:cytology / Q000196:embryology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002455:Cell Division; D002470:Cell Survival; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation; D011058:Pollen / Q000502:physiology; D012639:Seeds / Q000166:cytology*
D029681:Arabidopsis Proteins; C499608:MET1 protein, Arabidopsis; D004248:DNA (Cytosine-5-)-Methyltransferases