Sensitivity Of Acidovorax Citrulli To Copper Ions, Streptomycin And Shenqinmycin

Bacterial fruit blotch (BFB) of cucurbits, which is caused by Acidovorax Citrulli, is a serious threat to the water melon and melon industries. Many methods have been used for the control of the disease. The most common medicines are copper preparation and streptomycin. The resistance factor (RF) of streptomycin-resistant mutants of Xanthomonas oryzae Pv. oryzae relative to their parent strain was 388. The result proved resistance of pathogen was directly related to prevent plant bacteriosis. So deferring pesticide resistance and selecting other agents were the most methods to prevent bacterial fruit blotch. The nephelometry and minimal inhibitory concentration were used to study pesticide resistance of copper ions and streptomycin to Acidovorax Citrulli. The sensibility variation of Acidovorax Citrulli to copper preparation and streptomycin was compared, and we also evaluated the interaction of both medicine. We determined the average medium effective concentration (EC50) and minimal inhibition concentrations (MIC) of streptomycin against Acidovorax Citrulli, evaluated the interaction of copper preparation, streptomycin and shenqinmycin.The antimicrobial activity of copper ions and streptomycin against Acidovorax Citrulli was determined. The average medium effective concentration (EC50) and mostly minimal inhibition concentrations (MIC) of streptomycin against Acidovorax Citrulli were 14.65 μg/mL and 16 jxg/mL, the minimum and maximum of the EC50 were 7.3μg/mL and 61.74 μg/mL. These results demonstrated to have activity against most of bacterial fruit blotch strains, but streptomycin-resistant strains have been found. The EC50 values of copper ions against the Acidovorax Citrulli were more than 100 ug/mL, there were two of them more than 1000 μg/mL At the same time, the MIC values of copper ions against Acidovorax Citrulli were 1800 μg/mL, the serious pesticide resistance of copper ions against BFB strains were suggested. And the cross-resistance test showed that there was no cross-resistance between streptomyein and copper ions in Acidovorax Citrulli.The toxicity of shenqinmycin against 16 bacterial fruit blotch strains was studied. The results showed that shenqinmycin strongly inhibited the growth of Acidovorax Citrulli with the range of EC50 from 0.73 μg/mL to 1.22 μg/mL, while some of the strains had lower inhibitory activity with the EC50 reaching 38.10 μg/mL. The MIC values of which were more than 70 μg/mL, and there was obvious cross-resistance between shenqinmycin and streptomycin in Acidovorax Citrulli.