Data from: Functional characterization of Paillotin: An immune peptide regulated by the Imd pathway with pathogen-specific roles in Drosophila immunity

Insects, such as Drosophila melanogaster, rely on innate immune defenses
to combat microbial threats. Antimicrobial peptides (AMPs) play an
important role in limiting pathogen entry and colonization. Despite
intensive research into the regulation and biochemical properties of AMPs,
their exact significance in vivo has remained uncertain due to the
challenges of mutating small genes. Fortunately, recent technologies have
enabled the mutation of individual AMP genes, overcome previous obstacles,
and opened new avenues for research. In this study, we characterized one
novel host-defense peptide, Paillotin (IM18, CG33706), using
loss-of-function mutants. Paillotin is an ancient host defense peptide of
Diptera, regulated by the Imd pathway. Loss of Paillotin does not impact
the activity of either the Imd or Toll pathways. Importantly, we found
that Paillotin mutants are viable but exhibit increased susceptibility to
specific infections, particularly Providencia burhodogranariea. Paillotin
was further found to contribute synergistically to defense against P.
burhodogranariea when combined with other AMPs. However, we did not detect
direct microbicidal activity of Paillotin in vitro in our hands. Taken
together, our findings identify Paillotin as a novel host defense peptide
acting downstream of Imd signaling, advancing our understanding of the
Drosophila antimicrobial response.