A phytoplasma effector suppresses insect melanization immune response to promote pathogen persistent transmission.

ABSTRACT: Insect melanization triggered by the conversion of prophenoloxidase to active phenoloxidase via serine proteases (SPs) is an important immediate immune response. However, how phytoplasmas evade this immune response to promote their propagation in insect vectors remains unknown. Here, we demonstrate that infection of leafhopper vectors with rice orange leaf phytoplasma (ROLP) activates the mild melanization response in hemolymph. ROLP-encoded effector protein SRP1 is highly expressed in leafhopper hemolymph, where it competitively binds to SP2, thereby inhibiting SP2-mediated cleavage of prophenoloxidase into active phenoloxidase. Consequently, microinjection of SRP1 effectively suppresses the melanization response and enhances ROLP propagation. The histidine residue at position 23 of SRP1

SUBMITTER: Zhang XF 

PROVIDER: S-EPMC11777251 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature