Tolerance and overcompensation to infection by Phytophthora infestans in the wild perennial climber Solanum dulcamara

• Published in: Ecology and evolution 2019-04, Vol.9 (8), p.4557-4567
• Main Authors: Masini, Laura, Grenville‐Briggs, Laura J., Andreasson, Erik, Råberg, Lars, Lankinen, Åsa
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural Science; Agricultural Science, Forestry and Fisheries; Agricultural Sciences; Blight; Crop diseases; Crops; Epidemics; Evolutionary Biology; Evolutionsbiologi; Field study; Genetic diversity; Genotype & phenotype; Genotypes; host-pathogen interactions; Infections; Jordbruksvetenskap; Laboratories; Lantbruksvetenskap och veterinärmedicin; Lantbruksvetenskap, skogsbruk och fiske; Late blight; Leaves; Natural populations; Original Research; overcompensation; Phytophthora infestans; Plant biomass; Plant diseases; Plant protection; Plant resistance; Potatoes; Signs and symptoms; Solanum dulcamara; tolerance
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.5057

Studies of infection by Phytophthora infestans—the causal agent of potato late blight—in wild species can provide novel insights into plant defense responses, and indicate how wild plants might be influenced by recurrent epidemics in agricultural fields. In the present study, our aim was to investigate if different clones of Solanum dulcamara (a relative of potato) collected in the wild differ in resistance and tolerance to infection by a common European isolate of P. infestans. We performed infection experiments with six S. dulcamara genotypes (clones) both in the laboratory and in the field and measured the degree of infection and plant performance traits. In the laboratory, the six evaluated genotypes varied from resistant to susceptible, as measured by degree of infection 20 days post infection. Two of the four genotypes susceptible to infection showed a quadratic (concave downward) relationship between the degree of infection and shoot length, with maximum shoot length at intermediate values of infection. This result suggests overcompensation, that is, an increase in growth in infected individuals. The number of leaves decreased with increasing degree of infection, but at different rates in the four susceptible genotypes, indicating genetic variation for tolerance. In the field, the inoculated genotypes did not show any disease symptoms, but plant biomass at the end of the growing season was higher for inoculated plants than for controls, in‐line with the overcompensation detected in the laboratory. We conclude that in S. dulcamara there are indications of genetic variation for both resistance and tolerance to P. infestans infection. Moreover, some genotypes displayed overcompensation. Learning about plant tolerance and overcompensation to infection by pathogens can help broaden our understanding of plant defense in natural populations and help develop more sustainable plant protection strategies for economically important crop diseases. In this study, we investigated resistance and tolerance to infection by Phytophthora infestans, the causal agent of potato late blight, in the wild perennial climber Solanum dulcamara. Solanum dulcamara is a relative of potato and can be found as a weed in the agricultural landscape, suggesting that it can influence disease epidemiology of late blight. We detected genetic variation for tolerance and also that some genotypes show overcompensatory growth for intermediate levels of infection.