Detection of Xanthomonas axonopodis pv. phaseoli and Xanthomonas axonopodis pv. phaseoli var. fuscans on Phaseolus vulgaris

摘要

This method is derived from the validation studies carried out by ISTAin 2003, in collaboration with the International Seed Health Initiative for Vegetables (ISHI-Veg) (Sheppard and Remeeus, 2005). For routine testing of bean seed a combination of twocomplementary semi-selective media, MT and XCP1, is recommended with a pathogenicity test to confirm suspect isolates. The two media, XCP1 and MT, have been chosen for their ease of use and selectivity for X. axonopodis pv phaseoli. In addition both media can be used to detect both X. axonopodis pv phaseoli and X. axonopodis pv phaseolivar fuscans. Although initially the morphology of fuscans and non-fuscans strains of X. axonopodis pv phaseoli appear to be similar on the media after a longer incubation the fuscans colonies are distinguished by a distinct brown pigmentation. A further advantage of MT medium is that it can also be used for identifying other bacterial seed-borne pathogens of beans, e.g. Pseudomonas savastanoi pv. phaseolicola and Pseudomonas syringae pv. syringae.