title: Genetic and DNA-methylation changes induced by potassium dichromate in Brassica napus L.
abstract: This study evaluated genetic and DNA methylation alteration induced by potassium dichromate in Brassica napus L. plants. Amplified fragment length polymorphism (AFLP) and selective amplification of polymorphic loci (SAMPL) tests revealed dose-related increases in sequence alterations in plantlets exposed to 10-200 mg/l potassium dichromate. Individual plantlets exposed to chromium under similar conditions showed different AFLP and SAMPL DNA profiles. These observations suggest random DNA mutation in response to potassium dichromate and argue against preferential sites for mutation. DNA methylation changes in response to chromium treatment were also evaluated. Two complementary approaches were applied: (i) immunolabelling, using a monoclonal antibody against 5-methylcytosine; and (ii) methylation-sensitive amplified polymorphism (MSAP). Immunolabelling showed cytosine-hypermethylation in the Brassica napus L. genome when plants were treated with potassium dichromate. MSAP analysis showed extensive methylation changes in CCGG-sequences, with the net result being genome-wide hypermethylation. These results showed a clear DNA alteration in plants as a response to chromium exposure and the effect was dose-dependent. DNA polymorphism detected by different markers supports the effectiveness of the use of these tools for the investigation of environmental toxicology and for evaluating the concentration of pollutants by DNA analysis in plants.
authors.affiliation: Dipartimento di Scienze dell'Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy. massimo.labra@unimib.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Labra
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Grassi
authors.forename: Serena
authors.initials: S
authors.lastname: Imazio
authors.forename: Tiziana
authors.initials: T
authors.lastname: Di Fabio
authors.forename: Sandra
authors.initials: S
authors.lastname: Citterio
authors.forename: Sergio
authors.initials: S
authors.lastname: Sgorbati
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Agradi
mesh_terms: D000704:Analysis of Variance; D001483:Base Sequence; D029688:Brassica napus / Q000187:drug effects* / Q000235:genetics; D004249:DNA Damage; D019175:DNA Methylation / Q000187:drug effects*; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000032:analysis / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D009693:Nucleic Acid Hybridization / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D011192:Potassium Dichromate / Q000633:toxicity*
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D011192:Potassium Dichromate