Guangxi Zhiwu (Jan 2023)
Isolation, identification, and analysis on antibacterial activities of endophytic bacteria from Artemisia argyi var. argyi ‘Qiai’
Abstract
The composition of endophytic bacteria in different tissues of Artemisia argyi var. argyi ‘Qiai’, and the antibacterial activities of their secondary metabolites were the main focus of this study. The tissue culture method was used to isolate the endophytic bacteria from roots, stems and leaves of Artemisia argyi var. argyi ‘Qiai’ and then, the antibacterial activity of the volatiles from endophytic bacterial fermentation broth against six common pathogenic bacteria was assayed by the disk diffusion test. Meanwhile, the minimum inhibitory concentrations(MICs) and the minimum bactericidal concentrations(MBCs) were also determined. Finally, the isolated strains were identified based on phenotypical and biochemical properties as well as 16S rRNA gene sequencing. The results showed that, (1)among the thirteen strains isolated, strains lzy-21, lzy-20 and lzy-1 have strong capacity of producing cellulase, protease and lipase respectively. (2)The MICs of the volatiles of lzy-20 and wnn4-3 to Escherichia coli, Enterobacter aerogenes and Bacillus subtilis were all 16 μg·mL-1. The MBCs of the them were 32, 32, 16 μg·mL-1 and 16, 32, 32 μg·mL-1, respectively. (3)The MICs of lzy-12 against Staphylococcus aureus and Yersinia enterocolitica were 16 μg·mL-1, and the MBCs of them were 32 μg·mL-1 and 16 μg·mL-1, respectively. (4)The MICs of both lzy-17 and lzy-21 against Y. enterocolitica were 16 μg·mL-1, and the MBCs were 16 μg·mL-1 and 32 μg·mL-1 respectively. Strain lzy-1 was identified as Acinetobacter pittii, which was isolated from plants for the first time. lzy-20, lzy-21, wnn4-3, lzy-12, and lzy-17 were identified as Bacillus altitudinis, B. koreensis, B. siamensis, Luteibacter pinisoli, and Paenarthrobacter nicotinovorans, respectively. The above results lay a foundation for making full use of endophytic bacteria resources to produce industrial enzymes, and further exploring the mechanisms of how endophytic bacteria interact with Artemisia argyi var. argyi ‘Qiai’.
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