In vitro Investigation on Biocontrol of Xanthomonas axonopodis pv. citri Cause of Citrus Bacterial Canker by Citrus Antagonistic Bacteria

Citrus Bacterial Canker disease caused by Xanthomonas axonopodis pv. citri is one of the most important diseases of citrus in south of Iran. In this research, the samples of bacterial flora of citrus leaves were collected from various citrus growing areas of Hormozgan, Jiroft and Mazandaran.The epiphytic bacteria were isolated from those leaves during 2000 and 2001 years. From 453 isolates, 26 strains inhibited growth of Xanthomonas axonopodis pv. citri under in vitro conditions. The bacterial strains were analyzed based on physiological and biochemical characteristics such as fluorescent pigment production on king B media, oxidase and catalase reaction, gelatin, casein and tween 80 hydrolysis, levan production and utilization of hydrocarbon sources. Based on the these characteristics they were grouped on five classes including Pseudomonas fluorescens I, P.fluorescens V, P. viridiflava and P. syringae. The last group was aerobic and gram positive bacteria that produced spore and identified as Bacillus spp.