The plant pathogen Ralstonia solanacearum colonizes the xylem of plants, impeding fluid flow and causing a disease called wilt. This pathogen affects many types of commercially-important plants, including potatoes, tomatoes, soybeans, and even bananas.
Recently, researchers at the University of Wisconsin, Madison, described how this particular pathogen escapes from plant extracellular traps.
If you think “plant extracellular traps” sounds sounds eerily similar to “neutrophil extracellular traps”, you’d be right. Animal cells often produce so-called NETs that trap invading pathogenic bacteria. As always, these bacteria have a way to fight back - they produce DNases that degrade the NETs.
Turns out, the same is true of plant pathogens. The UW Madison group found that R. solanacearum secretes two DNases that help the bacteria escape extracellular traps. These traps are produced by plant border cells after they come into contact with the bacteria. In the case of R. solanacearum, the presence of bacterial flagellin induces the plant cells to secrete the traps.
The researchers knew that R. solanacearum produced two putative extracellular DNases, NucA and NucB. They decided to test whether these nucleases helped R. solanacearum escape from the plant extracellular traps.
Sure enough, bacteria lacking NucA and NucB were less virulent towards wilt-susceptible tomato plants.
Sources: PLOS Pathogens, Microbiology Bytes, Wikipedia