Isolation, identification and study the pathogenicity characteristics and biocontrol of bacterial citrus canker and tomato leaf spot causes

Abstract

Laboratory and greenhouse experiments were conducted at the plant protection department, Agriculture college, University of Sana’a to study the hypersensitive reaction and bacteriocine of citrus canker and tomato leaf spots isolates and evaluate the biocontrol effects of Bacillus coagulans and crude antibiotic against pathogenic bacteria for citrus and tomato. Fourteen isolates were isolated from Lemon Lemon's seedlings with citrus canker on GNA medium collected from Tehama district, Hodeida, Yemen. Xanthomonas campestris pv. citri was identified according to the pathogenicity (6 isolates were positive), morphological, physiological and biochemical characteristics. Positive reaction was shown for citrus canker isolates no. 5, 10, 11, 12 and 14 and tomato leaf spots isolates for HR test in tobacco cultivars, while Withinia sominefora had late reaction. Citrus canker isolates and tomato leaf spots isolate were could not produced of bacteriocin. The results of Bacillus coagulans clearly had more inhibitory effects against citrus canker isolates no. 14, 12, 9, 11 and 10 and tomato leaf spots isolate with means 30, 27.5, 27, 22.5, 20.8 and 20.5 mm respectively, however, Bacillus coagulans showed less effective on citrus canker isolates no.5, 8 and 2. Data showed that crude antibiotic of Bacillus coagulans had a strong antibacterial activity against citrus canker isolate no. 12 with mean 23 mm, but, no significant differences between two crude antibiotic effects which extracted by ethyl and benzene solutions, also, no significant differences were observed between product crude antibiotics in two media GNA and SPA on effect its of disease bacteria.