Effect of plant extracts on Pseudomonas syringae pv. actinidiae behavior
G. BURIANI (1), L. Fiorentini (2), A. Cellini (2), F. Spinelli (2) (1) University of Bologna, Italy; (2) University of Bologna, Italy

Pseudomonas syringae pv. actinidiae (Psa), the causative agent of the bacterial canker of kiwifruit,  was firstly isolated in 1992, but the pandemic outbreak occurred in 2008 and seriously threatened kiwifruit production worldwide. The molecular mechanisms involved in recognition/communication between Psa and the host plant has not been yet elucidated in spite of the high economic impact of this disease. Our findings shows that plant crude extracts or xylem juices of Actinidia deliciosa and A. chinensis were able to influence biofilm formation, Psa mobility and increase virulence in comparison with artificial growing media. This phenomenon was confirmed by QPCR analysis of biofilm, motility and virulence-related  gene expression. The gene expression responded differentially to the plant extract depending also to Psa density, suggesting an influence both by the host plant and the pathogen population density. The effect of non host plant extracts were also studied to determine the specificity Psa responses. Finally, crude plant extracts were fractioned and the single chemical fractions were tested on Psa in order to identify the chemical group to which belong the putative plant signals recognized by Psa. 

Abstract Number: P3-65
Session Type: Poster