Host Defense Peptide-Mimicking Poly(2-oxazoline)s Displaying Potent Activities toward Phytopathogens to Alleviate Antimicrobial Resistance in Agriculture

Given the limited types of agricultural bactericides and the rapid emergence of antimicrobial resistance, bacterial plant diseases pose a serious threat to agricultural production, which calls for effective antimicrobial agents with a low propensity for resistance. Host defense peptides (HDPs) have drawn significant attention for their broad-spectrum antimicrobial activity. In this study, we found that HPD-mimicking poly(2-oxazoline) Gly-POX₂₀ exhibits potent activity against bacterial phytopathogens, with superior antibacterial selectivity and proteolytic stability compared to the natural HDP melittin. Compared to commonly used agricultural bactericides, Gly-POX₂₀ displays more efficient antibiofilm activity and a lower propensity for resistance than does the antibiotic streptomycin, likely due to its antibacterial mechanism, which involves DNA interaction and generating lethal doses of ROS. <i>In vivo</i> studies reveal that Gly-POX₂₀ is effective in preventing and treating phytopathogens without observable damage to plant tissues, suggesting that poly(2-oxazoline) could be a promising bactericide for agricultural applications.