Gray Mold Suppression Conferred by the Host Antimicrobial Protein LsGRP1 Involves Main Pathogen-Targeted Manipulation of the Nonantimicrobial Region LsGRP1.

Antimicrobial protein LsGRP1 protects from gray mold mainly caused by the destructive pathogen ; however, its nonantimicrobial region LsGRP1 conversely promotes spore germination of this fungus. By assaying the effects of LsGRP1, LsGRP1, and the combination of LsGRP1 and the antimicrobial region LsGRP1 on fungal spore germination, hyphal growth, and gray mold development, LsGRP1 was found to improve the LsGRP1 sensitivity of and disease suppression by LsGRP1. cell vitality assays indicated that LsGRP1 pretreatment uniquely enhanced the lethal efficiency of LsGRP1 compared to the control peptides. In addition, LsGRP1-treated was demonstrated to lower infection-related gene expression and increase host-defense-eliciting activity, as indicated by reverse transcription quantitative polymerase chain reaction and histochemical-staining-based callose detection results, respectively. Therefore, LsGRP1 showed a novel mode of action for antimicrobial proteins by manipulating the main pathogen, which facilitated the development of target-specific and dormant microbe-eradicating antimicrobial agents.