Effect of hypermethylation of CCWGG sequences in DNA of Mesembryanthemum crystallinum plants on their adaptation to salt stress.
Under salt stress conditions, the level of CpNpG-methylation (N is any nucleoside) of the nuclear genome of the facultative halophyte Mesembryanthemum crystallinum in the CCWGG sequences (W = A or T) increases two-fold and is coupled with hypermethylation of satellite DNA on switching-over of C3-photosynthesis to the crassulacean acid metabolism (CAM) pathway of carbon dioxide assimilation. The methylation pattern of the CCWGG sequences is not changed in both the 5'-promoter region of the gene of phosphoenolpyruvate carboxylase, the key enzyme of C4-photosynthesis and CAM, and in the nuclear ribosomal DNA. Thus, a specific CpNpG-hypermethylation of satellite DNA has been found under conditions of expression of a new metabolic program. The functional role of the CpNpG-hypermethylation of satellite DNA is probably associated with formation of a specialized chromatin structure simultaneously regulating expression of a large number of genes in the cells of M. crystallinum plants on their adaptation to salt stress and switching-over to CAM metabolism.
Dyachenko
O V
OV
Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia.
Zakharchenko
N S
NS
Shevchuk
T V
TV
Bohnert
H J
HJ
Cushman
J C
JC
Buryanov
Ya I
YI
D000220:Adaptation, Biological / Q000187:drug effects / Q000502:physiology; D001483:Base Sequence; D019175:DNA Methylation; D018744:DNA, Plant / Q000737:chemistry* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D035723:Mesembryanthemum / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012639:Seeds / Q000166:cytology / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology*
D018744:DNA, Plant; D012965:Sodium Chloride