Unravelling the defence arsenal of the wild Solanum dulcamara to Pythophthora infestans: resistance and tolerance.
L. MASINI (1), K. Abreha (1), E. Alexandersson (1), L. Råberg (2), R. Vetukuri (1), L. Grenville-Briggs Didymus (1), E. Andreasson (1), I. Rieu (3), Å. Lankinen (1) (1) Swedish University of Agricultural Sciences (SLU), Sweden; (2) Lund University, Sweden; (3) Radboud University, Netherlands

Potato late blight, caused by the oomycete Phytophthora infestans, is a devastating disease that can wipe out a potato field within days. Solanum dulcamara is a diploid, perennial, wild relative of potato, and an occasional natural host for P. infestans in Sweden. A study on 12 populations originating from south-west Sweden detected remarkable disease variability in response to P. infestans. Our goal is to understand the cause of this variability, and identify new genes or pathways that can provide durable resistance against P. infestans. Because of the range of this variability, we hypothesize that more than one defence mechanism could exist in S. dulcamara. We have a BAC-clone from S. dulcamara which contains, potentially, the R-gene Rpi-dlc1. Sequencing of the BAC-clone and database search showed no homology to known R-genes, suggesting that the Rpi-dlc1 locus could contain a novel type of R-gene. Cloning is underway. In parallel, we are testing whether the variability in defence responses is due to tolerance, the ability of a plant to limit the negative impact of a pathogen on its fitness. Because tolerance, as opposed to resistance, does not affect the pathogen fitness, it could contribute to a slow-down in the co-evolution of the pathogen to overcome resistance. We are studying the relationship between plant fitness and degree of infection under controlled conditions in order to identify the most extreme phenotypes, which will be used for gene expression studies.

Abstract Number: P17-570
Session Type: Poster