Species-specific double-strand break repair and genome evolution in plants.
Even closely related eukaryotic species may differ drastically in genome size. While insertion of retroelements represents a major source of genome enlargement, the mechanism mediating species- specific deletions is fairly obscure. We analyzed the formation of deletions during double-strand break (DSB) repair in Arabidopsis thaliana and tobacco, two dicotyledonous plant species differing >20-fold in genome size. DSBs were induced by the rare cutting restriction endonuclease I-SCE:I and deletions were identified by loss of function of a negative selectable marker gene containing an I-SCE:I site. Whereas the partial use of micro-homologies in junction formation was similar in both species, in tobacco 40% of the deletions were accompanied by insertions. No insertions could be detected in Arabidopsis , where larger deletions were more frequent, indicating a putative inverse correlation between genome size and the average length of deletions. Such a correlation has been postulated before by a theoretical study on the evolution of related insect genomes and our study now identifies a possible molecular cause for the phenomenon, indicating that species-specific differences in DSB repair might indeed influence genome evolution.
Kirik
A
A
Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrabetae 3, D-06466 Gatersleben, Germany.
Salomon
S
S
Puchta
H
H
D017360:Arabidopsis / Q000235:genetics*; D015139:Blotting, Southern; D004260:DNA Repair / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D019143:Evolution, Molecular; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant; D016254:Mutagenesis, Insertional / Q000235:genetics; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion / Q000235:genetics; D013045:Species Specificity; D014026:Nicotiana / Q000235:genetics*; D014170:Transformation, Genetic; D019076:Transgenes / Q000235:genetics
D004269:DNA, Bacterial; D018744:DNA, Plant; D029701:Saccharomyces cerevisiae Proteins; C036483:T-DNA; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific