TitleReciprocal chromosome translocation associated with TDNA-insertion mutation in Arabidopsis: genetic and cytological analyses of consequences for gametophyte development and for construction of doubly mutant lines.
Publication TypeJournal Article
Year of Publication2009
AuthorsCurtis MJ, Belcram K, Bollmann SR, Tominey CM, Hoffman PD, Mercier R, Hays JB
Date Published2009 Mar
Arabidopsis, Arabidopsis Proteins, Chromosomes, Plant, DNA, Bacterial, DNA-Directed DNA Polymerase, Flowers, Gene Frequency, Genotype, Heterozygote, In Situ Hybridization, Fluorescence, Models, Genetic, Mutagenesis, Insertional, Mutation, Pollen, Translocation, Genetic

Chromosomal rearrangements may complicate construction of Arabidopsis with multiple TDNA-insertion mutations. Here, crossing two lines homozygous for insertions in AtREV3 and AtPOLH (chromosomes I and V, respectively) and selfing F1 plants yielded non-Mendelian F2 genotype distributions: frequencies of +/++/+ and 1/1 2/2 progeny were only 0.42 and 0.25%. However, the normal development and fertility of double mutants showed AtPOLH-1 and AtREV3-2 gametes and 1/1 2/2 embryos to be fully viable. F2 distributions could be quantitatively predicted by assuming that F1 selfing produced inviable (1,2) and (+,+) gametophytes 86% of the time. Some defect intrinsic to the F1 selfing process itself thus appeared responsible. In selfing AtREV3 (+/2 ) single mutants, imaging of ovules and pollen showed arrest or abortion, respectively, of half of gametophytes; however, gametogenesis was normal in AtREV3 ( 2/2 ) homozygotes. These findings, taken together, suggested that T-DNA insertion at AtREV3 on chromosome I had caused a reciprocal I-V translocation. Spreads of meiosis I chromosomes in selfing AtREV3 (+/2 ) heterozygotes revealed the predicted cruciform four-chromosome structures, which fluorescence in situ hybridization showed to invariably include both translocated and normal chromosomes I and V. Sequencing of the two junctions of T-DNA with AtREV3 DNA and the two with gene At5g59920 suggested translocation via homologous recombination between independent inverted-repeat T-DNA insertions. Thus, when crosses between TDNA-insertion mutants yield anomalous progeny distributions, TDNA-linked translocations should be considered.

Alternate JournalPlanta
PubMed ID19082841
PubMed Central IDPMC4186712
Grant ListT32 ES007060 / ES / NIEHS NIH HHS / United States