壳聚糖和2株芽孢杆菌对柑橘溃疡病菌的杀菌效果评价

柑橘溃疡病是重要的柑橘细菌性病害,为探明壳聚糖和枯草芽孢杆菌对柑橘溃疡病的防治潜力,本文用平板菌落计数法评价了3种粘度壳聚糖对柑橘溃疡病菌的杀菌效果,以改良的纸碟法测定2株枯草芽孢杆菌(Bacillus subtilis)发酵液对柑橘溃疡病菌的抑菌效果。综合处理0.5 h、3 h和6 h的结果显示,3种粘度壳聚糖对柑橘溃疡病的杀菌强弱依次为:粘度12粘度100粘度20。枯草芽孢杆菌菌株BS 101和54-6在YPG培养基中有氧发酵3 d产生发酵液原液的抑菌圈直径分别为3.45 cm和3.21 cm,比0.1 g/mL氨苄青霉素的抑菌圈分别大45%和35%。可见,发酵液中存在对溃疡病菌高度有效的成分。因此,认为粘度12的壳聚糖和芽孢杆菌菌株BS 101和54-6具有防治柑橘溃疡病的潜力。

Evaluation of antibacterial effects of chitosan and two strains of Bacillus against Xanthomonas citri subsp.citri

Citrus bacterial canker is an important citrus bacterial disease.In order to investigate the antibacterial potential of chitosan and bio-control Bacillus against Xanthomonas citri subsp.citri,plant colony counting was performed to evaluate the antibacterial effects of chitosan with three different viscosities against Xanthomonas citri subsp.citri,modified paper disk method was performed to measure the antibacterial effects of fermentation fluids of two strains of Bacillus subtilis against Xanthomonas citri subsp.citri.The results of chitosan treatment for 0.5 h,3 h and 6 h together show that the antibacterial ability of chitosan with three different viscosities against Xanthomonas citri subsp.citri is:viscosity 12 ＞ viscosity 100 ＞ viscosity 20.The fermentation fluids of Bacillus subtilis strains BS101 and 54-6 were obtained by shaking culture in YPG media for 3 days.The diameters of inhibition zones generated by these two kinds of fermentation fluids are 3.45 cm and 3.21 cm,respectively,which are 45％ and 35％ bigger than that generated by 0.1 g/mL Ampicillin,respectively.Thus it can be seen that there are highly effective components against Xanthomonas citri subsp.citri in the fermentation fluids.Therefore,chitosan with viscosity of 12 and Bacillus subtilis strains BS101 and 54-6 are regarded to have potential to prevent citrus bacterial canker.