Abstract Infection of Drosophila melanogaster adults with
Pseudomonas aeruginosa (PA14) can kill the flies within
48 h. We found that the virulence of PA14 was significantly
attenuated when treated with a reducing agent, dithiothreitol
(DTT), prior to infection. Infection with DTT-treated PA14
elevated Metchnikowin expression at 22 h post-infection and
the virulence of DTT-treated PA14 was not attenuated in Dif
and Relish mutants. These results suggest that DTT pretreatment
of PA14 can aggravate certain virulence factors that
may be required to paralyze fly immune responses, triggering
Metchnikowin expression via Dif and Relish activations.