Involvement of KU80 in T-DNA integration in plant cells

Jianxiong Li, Manjusha Vaidya, Charles White, Alexander Vainstein, Vitaly Citovsky, Tzvi Tzfira

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


In Agrobacterium-mediated genetic transformation of plant cells, the bacterium exports a well defined transferred DNA (T-DNA) fragment and a series of virulence proteins into the host cell. Following its nuclear import, the single-stranded T-DNA is stripped of its escorting proteins, most likely converts to a double-stranded (ds) form, and integrates into the host genome. Little is known about the precise mechanism of T-DNA integration in plants, and no plant proteins specifically associated to T-DNA have been identified. Here we report the direct involvement of KU80, a protein that binds dsT-DNA intermediates. We show that ku80-mutant Arabidopsis plants are defective in T-DNA integration in somatic cells, whereas KU80-overexpressing plants exhibit increased susceptibility to Agrobacterium infection and increased resistance to DNA-damaging agents. The direct interaction between dsT-DNA molecules and KU80 in planta was confirmed by immunoprecipitation of KU80 dsT-DNA complexes from Agrobacterium-infected plants. Transformation of KU80-overexpressing plants with two separate T-DNA molecules resulted in an increased rate of extrachromosomal T-DNA to T-DNA recombination, indicating that KU80 bridges between dsT-DNAs and double-strand breaks. This last result further supports the notion that integration of T-DNA molecules occurs through ds intermediates and requires active participation of the host's nonhomologous end-joining repair machinery.

Original languageEnglish
Pages (from-to)19231-19236
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number52
StatePublished - 27 Dec 2005
Externally publishedYes


  • Agrobacterium
  • DNA repair
  • Double-strand breaks

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Involvement of KU80 in T-DNA integration in plant cells'. Together they form a unique fingerprint.

Cite this