Participation of Xanthomonas axonopodis pv. citri hrp cluster in citrus canker and in non-host plants response

DUNGER, GERMÁN; ARABOLAZA, ANA L.; GOTTIG, NATALIA; ORELLANO, ELENA G.; OTTADO, JORGELINA

PLANT PATHOLOGY

Blackwell Publishing

Año: 2005 vol. 54 p. 812 - 819

0032-0862

Xanthomonas axonopodis pv. citri causes citrus canker, a serious disease of the citrus genus that results in important losses in citriculture regions. Type III secretion system, indispensable for the trafficking of proteins to the plant cell in pathogenicity and avirulence models, is encoded by hrp (hypersensitive response and pathogenicity) cluster. In this study we have characterized the participation of X. axonopodis pv. citri hrp cluster in the interaction with host and non-host plants. We isolated a region of the hrp cluster of X. axonopodis pv. citri and we constructed mutants in the operons hrpB and hrpD and the hrpF gene. Bacteria mutant strains failed to produce canker in citrus plants or hypersensitive response in cotton plants. We also characterized the interaction of the phytopathogen with different non-host plants. The results show that hypersensitive response is produced in leaves of cotton, bean, tobacco, tomato, pepper and Nicotiana benthamiana and that genes present in operons hrpB and hrpD and the hrpF gene are required for pathogenicity in hosts and hypersensitive response induction in non-host plants.