Major chromosomal rearrangements induced by T-DNA transformation in Arabidopsis.
We show that major chromosomal rearrangements can occur upon T-DNA transformation of Arabidopsis thaliana. In the ACL4 line, two T-DNA insertion loci were found; one is a tandem T-DNA insert in a head-to-head orientation, and the other is a truncated insert with only the left part of the T-region. The four flanking DNA regions were isolated and located on the Arabidopsis chromosomes; for both inserts, one side of the T-DNA maps to chromosome 2, whereas the other side maps to chromosome 3. Both chromosome 3 flanking regions map to the same location, despite a 1.4-kb deletion at this point, whereas chromosome 2 flanking regions are located 40 cM apart on the bottom arm of chromosome 2. These results strongly suggest a reciprocal translocation between chromosomes 2 and 3, with the breakpoints located at the T-DNA insertion sites. The interchanged fragments roughly correspond to the 20-cM distal ends of both chromosomes. Moreover, a large inversion, spanning 40 cM on the genetic map, occurs on the bottom arm of chromosome 2. This was confirmed by genetic analyses that demonstrated a strong reduction of recombination in the inverted region. Models for T-DNA integration and the consequences for T-DNA tagging are discussed in light of these results.
Nacry
P
P
Laboratoire de Biologie Cellulaire, Institut National de la Recherche Agronomique, 78026 Versailles Cedex, France.
Camilleri
C
C
Courtial
B
B
Caboche
M
M
Bouchez
D
D
D017360:Arabidopsis / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D005822:Genetic Vectors; D007612:Kanamycin / Q000494:pharmacology; D016254:Mutagenesis, Insertional; D010641:Phenotype; D011995:Recombination, Genetic / Q000187:drug effects / Q000235:genetics; D012231:Rhizobium / Q000235:genetics; D014178:Translocation, Genetic / Q000235:genetics*
D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; C036483:T-DNA; D007612:Kanamycin