Agrobacterium tumefaciens is a soil bacterium that uses a type VI secretion system (T6SS) to enable plant colonization. Ma et al. now describe a new family of T6SS effectors that have DNase activity (the Tde family) and provide A. tumefaciens with a competitive advantage in planta. Tde1 and Tde2 were shown to degrade DNA when expressed in Escherichia coli but A. tumefaciens is protected against their toxic effects owing to the presence of the antitoxin proteins, Tdi1 and Tdi2, respectively. Importantly, mutant A. tumefaciens strains that lack each of the toxin–antitoxin pairs were less able to survive than wild-type A. tumefaciens strains or Pseudomonas aeruginosa — an opportunistic plant pathogen — following co-infiltration into plant leaves. These data show that A. tumefaciens uses Tde toxins to attack and outcompete both siblings and other species during plant colonization.
References
Ma, L.-S. et al. Agrobacterium tumefaciens deploys a superfamily of type VI secretion DNase effectors as weapons for interbacterial competition in planta. Cell Host Microbe 16, 94–104 10.1016/j.chom.2014.06.002 (2014)
Rights and permissions
About this article
Cite this article
Nunes-Alves, C. New weapons for plant colonization. Nat Rev Microbiol 12, 594 (2014). https://doi.org/10.1038/nrmicro3336
Published:
Issue Date:
DOI: https://doi.org/10.1038/nrmicro3336
