Biocontrol of soft rot-causing Pectobacterium carotovorum in Chinese cabbage (Brassica rapa L. subsp. pekinensis) using antimicrobial peptide-fused endolysin CecA1–8-PlyPw

Pectobacterium spp., Gram-negative phytopathogens that cause soft rot disease, impose a significant economic burden on global food supply by inducing severe crop losses. Although antibiotic-based agrochemicals have been employed to control these pathogens, there is an urgent need to develop alternatives to address antimicrobial resistance (AMR) within the One Health framework. Here, by exploiting the ability of antimicrobial peptides (AMPs) to disrupt the outer membrane of Gram-negative bacteria, we developed AMP-fused endolysins as novel biocontrol agents against Pectobacterium spp. While the newly identified putative endolysin PlyPw, retrieved from a genome database, exhibited weak intrinsic antibacterial activity, fusing it with AMPs significantly enhanced its bactericidal activity. Among them, CecA 1–8 -PlyPws—the constructs fused with the octapeptide AMP, Cecropin A (1−8)—achieved a reduction of more than 5-log in Pectobacterium carotovorum Pcc21 within 1 h. A broad bacteriolytic spectrum—with activity against other Gram-negative and Gram-positive pathogens, even in the stationary growth phase—and stability across a wide range of temperatures and pH suggest potential for diverse applications of CecA 1–8 -PlyPws. CecA 1–8 -PlyPws significantly alleviated soft rot symptoms in harvested Chinese cabbage and seedling models and also demonstrated anti- Pectobacterium activity in soil, highlighting their potential as alternatives to agrochemicals throughout the crop supply. Furthermore, preliminary safety assays confirmed a favorable safety profile, as the endolysins exhibited no phytotoxicity on plant seedlings and no hemolytic activity against animal red blood cells. In the context of the ongoing AMR crisis, CecA 1–8 -PlyPws represent a promising sustainable strategy to reduce agricultural food losses related to bacterial diseases while promoting environmental safety. • Antibacterial activity of putative endolysin PlyPw is increased by AMP fusion. • Fusing PlyPw with CecA 1–8 significantly enhances its anti- Pectobacterium activity. • CecA 1–8 -PlyPws alleviate soft rot in postharvest and seedlings of Chinese cabbage. • CecA 1–8 -PlyPws reduce the number of Pectobacterium spp. cells in the soil. • CecA 1–8 -PlyPws can contribute to food security as alternative agrochemicals.