A novel biocontrol strain Pseudomonas canadensis FRPC18 against box blight (causative agent Calonectria pseudonaviculata)

Abstract

Abstract Background Recent box blight epidemics caused by Calonectria pseudonaviculata (Cps) have created the need for finding eco-friendly management strategies, especially in natural habitats. In the present research, the biocontrol activity of 26 bacterial isolates against Cps was investigated under laboratory and greenhouse conditions in a completely randomized design (n = 3; P < 0.05). Results Strains FRPC18, FRPF4, and FRPF6 showed the most efficiency in the inhibiting Cps colony by 72.4, 46.8, and 34.2% through a dual culture test, respectively. The superior strain, FRPC18, identified belonged to Pseudomonas canadensis. FRPF6 volatile and FRPC18 non-volatile antifungal compounds resulted in the highest inhibition rate of 27.67 and 59.43%, respectively. Strain FRPC18 could also produce the maximum amount of chitinase, significantly, while the highest amount of siderophores was detected in FRPF4. There were non-significant differences among the bacterial strains in producing protease and pectinase. In the greenhouse, FRPC18 reduced box blight severity by 30% and had non-statistically significant differences with Serenade® as a biofungicide (P < 0.05). Conclusion The results of this study suggest that P. canadensis may be a new biocontrol agent for controlling box blight in disease hotspots during epidemics in boxwood forests.