Menu:
Research
The Department of Plant Pathology and Microbiology
The Robert H. Smith Faculty of Agriculture, Food and Enviroment
The Hebrew University of Jerusalem
Identification of Xanthomonas campestris pv. vesicatoria (Xcv) genes induced during pathogenesis using IVET
Xcv is the causal agent of the bacterial spot disease in tomato and pepper. Bacterial spot has great economic importance, especially in places with high temperature and relative humidity that are conducive to the disease. Xcv is also considered a model bacterium in investigation of plant-pathogen interactions. Despite the large amount of knowledge that has accumulated on plant-pathogen interactions, many determinants involved in pathogenicity are largely unknown, and how these determinants function to promote disease is still unclear. In our lab, we developed a genetic approach to identify novel genes from Xcv that contribute to bacterial virulence and fitness. The approach is based on the In Vivo Expression Technology (IVET), which allows identification of bacterial genes that are expressed during the pathogen-host interaction but not, or to very low levels, in culture. Several interesting Xcv in vivo induced (ivi) genes have been detected and are being currently characterized. We generated several mutant strains for some of the ivi genes, and some of them showed reduced virulence, relative to the wild type strain.
A citH gene, encoding a citrate transporter in Xcv, was one of the genes
detected by the IVET approach. When mutated, this gene lead to a reduced virulence of the
bacterium on tomato. Left: symptom development on a tomato leaflet, 9 days after syringe
infiltration with an Xcv citH mutant strain (left side) and with the wild type strain
(right side). Right: in planta growth of the citH mutant strain (pink) compared to the
wild type strain (blue) following dip inoculation of tomato plants (Tamir et al., Journal of Bacteriology
2007).