Biofilm formation, epiphytic fitness and canker development in Xanthomonas axonopodis pv. citri

RIGANO, LUCIANO; SICILIANO, FLORENCIA; ENRIQUE, RAMÓN; SENDÍN, LORENA; FILIPPONE, PAULA; TORRES, PABLO; QÜESTA, JULIA; MAXWELL, DOW; CASTAGNARO, ATILIO; VOJNOV, ADRIÁN; MARANO, MARIA

MOLECULAR PLANT-MICROBE INTERACTIONS

American Phytopathological Society

Lugar: St. Paul MN USA; Año: 2007 vol. 20 p. 1222 - 1230

0894-0282

The phytopathogenic bacterium, Xanthomonas axonopodis pv. citri (Xac), is responsible for the canker disease affecting citrus plants throughout the world. Here we have evaluated the role of bacterial attachment and biofilm formation in leaf colonization during canker development on lemon leaves. Crystal violet staining and confocal laser scanning microscopy analysis of Xac strains expressing the green fluorescent protein were used to evaluate attachment and biofilm formation on abiotic and biotic (leaf) surfaces. Wild-type Xac attached to and formed a complex, structured biofilm on glass in minimal medium containing glucose. Similar attachment and structured biofilm formation were also seen on lemon leaves. A Xac gumB mutant strain, defective in production of the extracellular polysaccharide xanthan, did not form a structured biofilm on either abiotic or biotic surfaces. In addition, the Xac gumB showed reduced growth and survival on leaf surfaces and reduced disease symptoms. These findings suggest an important role for formation of biofilms in the epiphytic survival of Xac prior to development of canker disease.