Bioactivities of Pseudomonas aeruginosa HZ15

Abstract:

[Background] We have discovered that Pseudomonas aeruginosa HZ15 isolated from Macrobrochis gigas has a strong antagonistic effect against tobacco black shank. However, other biological activities of this strain remain to be explored. [Objective] To investigate the bioactivities of strain HZ15 in agriculture and provide a theoretical basis for the application of this strain in agricultural production and the development of biocontrol agents with this strain. [Methods] The agar diffusion method, plate confrontation, feeding method, bioassay, and pot and field experiments were employed to examine the antimicrobial, plant growth-promoting, insecticidal, and herbicidal (against ryegrass) activities of strain HZ15. [Results] Strain HZ15 showcased strong inhibitory activities against four species of plant pathogenic bacteria and the inhibition rates over 60% against 11 species of plant pathogenic fungi, exhibiting a broad antimicrobial spectrum. The pot experiment showed that the strain had a control effect of 52.48% against tobacco bacterial wilt, which was comparable to that of 52% chloroisobromine cyanuric acid·copper sulfate soluble powder diluted by 800 times. The field experiment showed that strain HZ15 significantly increased the number of tobacco leaves and the maximum leaf area. In addition, both strain HZ15 and its secondary metabolites exhibited strong toxicity against Solenopsis invicta and Caenorhabditis elegans, with the supernatant and bacterial culture showing the strongest toxic effects on S. invicta and C. elegans, respectively. In addition, strain HZ15 inhibited the germination of ryegrass by 63.80% and significantly reduced the root length, stem length, and fresh weight of ryegrass. [Conclusion] P. aeruginosa HZ15 possesses antimicrobial, plant growth-promoting, insecticidal, and ryegrass growth-inhibiting activities, demonstrating significant potential for application in agriculture and environmental management.

Key words:Pseudomonas aeruginosa;bioactivity;antimicrobial activity;insecticidal activity;herbicidal activity