Alginate gene expression by Pseudomonas syringae pv. tomato DC3000 in planta

• Published in: Phytopathology Vol. 94; no. 6
• Main Authors: Keith, R C, Keith, L M, Hernandez-Guzman, G, Uppalapati, SR, Bender, CL
• Format: Journal Article
• Language: English
• Published: 01.06.2004
• Subjects: Pseudomonas syringae
• ISSN: 0031-949X

P. syringae produces the exopolysaccharide alginate. In this study, an algD::uidA transcriptional fusion (pDCalgDP) was constructed to monitor alginate gene expression in plants inoculated with P. syringae pv. tomato DC3000. When susceptible collard plants were spray-inoculated with DC3000(pDCalgDP), algD was activated 72 hours post-inoculation (hpi) and was associated with the development of water-soaked lesions. In susceptible tomato cv. Rio Grande-PtoS, algD activity was lower than in collard and was not associated with watersoaking. The expression of algD was also monitored in tomato cv. Rio Grande-PtoR, which is resistant to the pathogen. 12 hpi, micro-HR was observed in Rio Grande-PtoR spray-inoculated with P. syringae pv. tomato DC3000(pDCalgDP). Results indicate that algD is expressed in both susceptible and resistant host plants. This study demonstrates alginate gene expression in planta, indicating that alginate gene expression occurs in both compatible and incompatible plant host-pathogen interactions.