Location: Plant Gene Expression CenterTitle: A rapid seedling resistance assay identifies wild tomato lines that are resistant to Psuedomonas syringe pv. tomato race 1
|Hassan, Jana - University Of California|
|Zhou, Yanming - University Of California|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2017
Publication Date: 6/21/2017
Citation: Hassan, J., Zhou, Y.J., Lewis, J.D. 2017. A rapid seedling resistance assay identifies wild tomato lines that are resistant to Psuedomonas syringe pv. tomato race 1. Molecular Plant-Microbe Interactions. 30(9):701-709. doi:10.1094/MPMI-11-16-0247-R.
Interpretive Summary: Pseudomonas syringae causes substantial disease under appropriate environmental conditions. We developed a rapid high-throughput screen to identify wild species of tomato with resistance to P. syringae. Common cultivars of tomato lack resistance to the strains of P. syringae that are now observed in agricultural settings. The seedling-based screen allows for reduced plant growth time and large sample sizes, which expedites the search for resistance to bacteria. We identified several wild species with complex genetic resistance to P. syringae. New sources of resistance can then be introduced into cultivars, which will improve the anti-microbial resistance of tomato with better genetic resources for plant breeders and growers, and will provide consumers with enhanced food security.
Technical Abstract: Bacterial speck caused by Pseudomonas syringae has historically been controlled by the Pto/Prf gene cluster. Emerging strains like P. syringae pv. tomato race 1 overcome resistance conferred by Pto/Prf, and can cause serious crop loss under appropriate environmental conditions. We developed a rapid assay to screen wild tomato seedlings for resistance to P. syringae pv. tomato race 1. We established the seedling resistance assay using the well-characterized P. syringae pv. tomato race 0 strain, DC3000, which is recognized in tomato cultivars carrying Pto/Prf (PtoR) and causes disease in isogenic lines lacking this cluster (PtoS). We optimized infectious conditions for P. syringae on tomato seedlings and demonstrated that tomato seedlings respond like adult tomato plants in critical measures of susceptibility and immunity, including the hypersensitive response, rapid ion leakage, restricted bacterial proliferation, and phenotypic resistance. After establishing infectious conditions for P. syringae pv. tomato race 1 on tomato seedlings, we screened 96 wild accessions and identified two accessions with strong P. syringae pv. tomato race 1 resistance, Solanum neorickii LA1329 and S. habrochaites LA1253, which are also resistant to bacterial infection as adult plants. This rapid high throughput seedling assay has many advantages, including reduced plant growth time and large sample sizes, and will allow for large-scale screening of resistance in tomato.