title: Variation of genomic DNA  methylation in the nitrate reductase gene of sibling tobacco (Nicotiana  tabacum) cultivars.
abstract: To  better understand genomic DNA methylation in sibling plant cultivars,  methylation-sensitive amplification polymorphism analysis was used to  investigate two sibling tobacco cultivars, Yunyan85 and Yunyan87, and their two  parents, K326 and Yunyan No. 2. Differences in the degree of genomic DNA  methylation were found among the four tobacco cultivars. Compared with parents,  the two sibling cultivars had fewer methylated sites. Twenty-nine  methylation-sensitive amplification polymorphism fragments that exhibited  methylation alteration in the four tobacco cultivars were recovered and  sequenced. BLAST (nucleotide BLAST) searches showed that two of the 29  sequences have 99% similarity with nucleotides 1442-1694 of the nia-1 gene  and the other 27 sequences contain GC, CAAT or TATA box. The nitrate reductase  genes from Yunyan87, K326 and Yunyan No. 2 were found to be identical; however,  the third intron of the nitrate reductase gene from Yunyan85 was different  compared to the third introns of Yunyan87, K326 and Yunyan No. 2. We conclude  that methylation alteration of promoter regions could be responsible for the  different phenotypes in tobacco and that introns of the nitrate reductase gene  can vary as a result of intra-species crossing in tobacco.
authors.affiliation: Agronomic College, Sichuan Agricultural University, Chengdu, China.
authors.forename: S L
authors.initials: SL
authors.lastname: Fu
authors.forename: Z X
authors.initials: ZX
authors.lastname: Tang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: L M
authors.initials: LM
authors.lastname: Lu
authors.forename: Y B
authors.initials: YB
authors.lastname: Huang
mesh_terms: D001483:Base Sequence; D019175:DNA Methylation; D017931:DNA Primers; D018744:DNA, Plant / Q000378:metabolism; D014644:Genetic Variation; D008969:Molecular Sequence Data; D050901:Nitrate Reductase / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics*
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D050901:Nitrate Reductase