Synthetic Hexadecapeptide Prevents Postharvest Pectobacterium carotovorum (subsp. brasiliensis BC1) Infection via Destabilizing Cell Envelope and Suppressing Biosynthesis of Arginine and Peptidoglycan

Abstract

Pectobacterium carotovorum is a Gram-negative plant-specific pathogen that causes severe rot of postharvest vegetables. Given the safety consideration of pesticides, we developed a peptide approach to address this issue. This hexadecapeptide (zp16) inhibited the growth of planktonic bacterial cells at micromolar concentration and reduced the live bacterial count in a cabbage leaf. Mechanistic studies revealed that zp16 rapidly influenced membrane potential and permeability and triggered significant reactive oxygen species accumulation. Furthermore, proteomics analysis suggested that the expression of some critical proteins related to arginine and peptidoglycan biosynthesis was statistically significantly down-regulated after transitory zp16 treatment. Collectively, zp16 kills the bacteria not only by physically damaging the cellular envelope but also interfering with multiple metabolic processes.