Experimental study reveals effective colonization and suppression of angular leaf spot in cucumber by endophytic bacteria, indicating potential for sustainable biological control.
Key Points
Evaluate the biocontrol efficacy and tissue colonization dynamics of endophytic bacteria isolated from healthy cucumbers against the angular leaf spot pathogen Pseudomonas syringae pv. lachrymans.
Screened 24 endophytic bacterial isolates from healthy cucumber tissues for biocontrol attributes, including indole-3-acetic acid production, siderophore synthesis, phosphate solubilization, and in vitro pathogen inhibition.
Conducted pot experiments to evaluate candidate strains against P. syringae pv. lachrymans, identified the top isolates via 16S rRNA sequencing, and quantified bacterial populations in seeds, roots, and shoots over 45 days.
Identified two top-performing biocontrol isolates, CB361-80 and CC372-83, which showed 99% sequence similarity to Ochrobactrum pseudintermedium and Pantoea agglomerans, respectively.
Achieved high seed colonization (3 × 10⁶ to 7.1 × 10⁷ CFU/g at day 1) and sustained long-term colonization in roots (2 × 10⁴ to 7.5 × 10⁴ CFU/g) and shoots (3.8 × 10⁴ to 2.2 × 10⁵ CFU/g) at 45 days post-inoculation without population decline following pathogen exposure.