جداسازی و شناسایی باکتری‌های اندوفیت قابل کشت مرکبات و ارزیابی آنها در کنترل باکتری Xanthomonas citri pv. citr، عامل شانکر باکتریایی مرکبات

Citrus bacterial canker caused by Xanthomonas citri pv. citri (Xcc) is one of the most devastating diseases which affects different species of citrus trees. Citrus bacterial canker is the most common disease in the citrus orchards of Kohgiluyeh and Boyer-Ahmad province, which annually causes significant damage to Mexican lime orchards. In this study, biocontrol efficiency of the Xcc by the endophytic bacteria isolated from the citrus leaves of the citrus orchards of the mentioned province was investigated. During the 2021 survey in Kohgiluyeh and Boyer-Ahmad province, sixty isolates of endophytic bacteria were isolated from citrus leaves and the biocontrol ability of these isolates in inhibiting the growth of Xcc on nutrient agar medium was studied. The results showed that only five isolates could specifically prevent the growth of Xcc bacterium under laboratory conditions. Based on the results of phenotypic and biochemical tests and the sequence of 16S rRNA gene, the isolates were identified as Pseudomonas fluorescens and Bacillus spp. Investigating the mutual effects of Xcc and endophytic bacteria in the greenhouse conditions, showed that there was no significant difference between the treatments with/without endophytes. However, P. fluorescens isolates showed more ability than Bacillus spp. in biocontrol of Xcc. In conclusion, according to the results the isolates of these two species of endophytic bacteria inhibited the growth of Xcc in the culture medium under laboratory conditions, but they had no effect on the disease severity of citrus bacterial canker in Mexican lime under greenhouse conditions and did not show a significant difference compared to the control.