title: Cascade of chromosomal rearrangements caused by a heterogeneous T-DNA integration supports the double-stranded break repair model for T-DNA integration.
abstract: Transferred DNA (T-DNA) from Agrobacterium tumefaciens can be integrated into the plant genome. The double-stranded break repair (DSBR) pathway is a major model for T-DNA integration. From this model, we expect that two ends of a T-DNA molecule would invade into a single DNA double-stranded break (DSB) or independent DSBs in the plant genome. We call the later phenomenon a heterogeneous T-DNA integration, which has never been observed. In this work, we demonstrated it in an Arabidopsis T-DNA insertion mutant seb19. To resolve the chromosomal structural changes caused by T-DNA integration at both the nucleotide and chromosome levels, we performed inverse PCR, genome resequencing, fluorescence in situ hybridization and linkage analysis. We found, in seb19, a single T-DNA connected two different chromosomal loci and caused complex chromosomal rearrangements. The specific break-junction pattern in seb19 is consistent with the result of heterogeneous T-DNA integration but not of recombination between two T-DNA insertions. We demonstrated that, in seb19, heterogeneous T-DNA integration evoked a cascade of incorrect repair of seven DSBs on chromosomes 4 and 5, and then produced translocation, inversion, duplication and deletion. Heterogeneous T-DNA integration supports the DSBR model and suggests that two ends of a T-DNA molecule could be integrated into the plant genome independently. Our results also show a new origin of chromosomal abnormalities.
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Yufei
authors.identifier: http://orcid.org/0000-0003-4392-6930
authors.initials: Y
authors.lastname: Hu
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Chen
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.|State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangzhou, 510642, China.
authors.forename: Chuxiong
authors.initials: C
authors.lastname: Zhuang
authors.affiliation: Instrumental Analysis and Research Center, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Jilei
authors.initials: J
authors.lastname: Huang
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics*; D032461:Chromosomes, Plant / Q000235:genetics*; D053903:DNA Breaks, Double-Stranded; D004269:DNA, Bacterial / Q000235:genetics*; D009154:Mutation; D030821:Plants, Genetically Modified / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; C036483:T-DNA
keywords: 
  Agrobacterium tumefaciens
  ; 
  Arabidopsis thaliana
  ; 
  DSB
  ; 
  DSBR
  ; chromosomal rearrangement; heterogeneous T-DNA integration