Unculturable bacteria exploit a secretory protein to antagonize insect melanization for persistent infection.

ABSTRACT: Phloem-inhabiting unculturable bacterial pathogens are persistently transmitted by insect vectors. However, how they evade insect immune responses to ensure persistent transmission remains unknown. The important melanization immune response in insects is triggered by cleavage of prophenoloxidase (PPO) into active phenoloxidase (PO) via clip-domain serine proteases (CLIPs). Here, we demonstrate that infection of Candidatus Liberibacter asiaticus (CLas) in psyllid vectors activates the peptidoglycan recognition protein (PGRP)-CLIP1-CLIP4-PPO-PO signaling cascade to induce a mild melanization response, ensuring persistent CLas infection without causing significant insect fitness costs to the insect. A CLas-encoded secretory protein, SDE3230, directly interacts with

SUBMITTER: Li Y 

PROVIDER: S-EPMC12506112 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature