Inactivation of Xanthomonas citri subsp. citri and Effect on Infection of Citrus Canker by Gamma Irradiation

Abstract

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) has been quarantined by many countries in the world. Recently, the usage of methyl bromide should be limited, application by gamma irradiation on the agricultural production is raised as an alternative method. In this study, the level of gamma irradiation which could decrease of population of Xcc in the suspension or on the surface of citrus fruit was investigated. The D 10 value of Xcc, which is radiation dose required to reduce the number of the microorganism, was 55 and 28 Gy in the suspension and on the surface of citrus fruit, respectively. Furthermore, disease severity was suppressed on the citrus leaves inoculated with Xcc suspension pre-treated with gamma irradiation. Based on this study, it is suggested that Xcc on the citrus fruit could be eradicated by gamma irradiation and the results of this study may be valuable for application of gamma ray in quarantine activity.

Effect of X-irradiation on Citrus Canker Pathogen Xanthomonas citri subsp. citri of Satsuma Mandarin Fruits

“…They were completely inactivated at 2.5 kGy, the total lethal dose ( Clavero et al, 1994 ; Lee et al, 2006 ). In our previous study, Xcc was very sensitive to γ-irradiation and its total lethal dose was between 300 and 400 Gy ( Kim et al, 2014 ). This dose was lower than that for E. coli which is known to be a microorganism sensitive to radiation ( Mayer-Miebach et al, 2005 ).…”