How do plants defend themselves against bacterial wilt? Understanding tomato responses to the pathogen Ralstonia solanacearum.

• Applicant: Dr. Annett Milling
• Subject Area: Plant Breeding and Plant Pathology
• Term: from 2008 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 75241257

Bacterial wilt of potato and tomato is caused by diverse strains of Ralstonia solanacearum, including strains adapted to tropical or temperate conditions. Host resistance is the only practical way to control bacterial wilt, but the basis of host wilt resistance is not understood. Further, nothing is known about how natural hosts like tomato defend themselves against R. solanacearum. To address these deficiencies, I propose to determine and compare the gene expression profiles of resistant and susceptible tomato plants infected with either a Race 1 tropical strain or a Race 3 temperate strain of R. solanacearum. Preliminary results using Northern blotting and quantitative PCR analysis suggest that resistant plants launch a stronger defense in response to infection with the tropical strain, while the temperate strain appears to calm defense responses in both tomato lines, possibly facilitating latent infection. To broaden and confirm these results, I propose to use a commercially available tomato microarray to quantify global host gene expression during bacterial wilt pathogenesis. A four-way experimental design will allow identification of the signal transduction pathways and functions involved in tomato wilt resistance.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Caitilyn Allen