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

Abstract

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.

Quantitative resistance differences between and within natural populations of Solanum chilense against the oomycete pathogen Phytophthora infestans

“…A study on six natural genotypes of bittersweet, Solanum dulcamara , showed differences in tolerance and resistance against P . infestans and interestingly highlights a mechanism of overcompensation in some genotypes with increase in shoot length and number of flowers in plants with higher disease levels (Masini et al., 2019). Ultimately, these studies highlight host genotype‐specific differences in resistance to biotic stress in wild plant species and show the potential of natural populations to be a valuable resource to explore and exploit quantitative resistance for evolutionary and economical aspects.…”

Sandstorms damage the photosynthetic activities of Haloxylon ammodendron seedlings

“…No difference was found when the blowing of sand-free wind and sand-carrying wind lasted 10 min; it is possible that such a short time of wind-blown sand did not cause sufficient impact to green assimilative branches, and the total photosynthetic electron transfer capacity of the photosynthetic apparatus was not greatly affected. There was no further decrease in rETR after 40 min of sand-carrying wind, and the slight increase in rETR after 20 and 40 min of sand-free wind was probably due to the compensating and overcompensating effects of photosynthetic function after the removal of adversity (Dyer et al 1991;Gaudet and Keddy 1998;Masini et al 2019).…”

Legume root diseases

“…In some pathosystems, partial resistance may occur in combination with tolerance traits Mikaberidze and McDonald, 2020). However, determination of the relative contribution of partial resistance and tolerance traits to disease reaction outcomes in variable field environments is difficult (Simms and Triplett, 1994;Masini et al, 2019;Pagan and Garcia-Arenal, 2020). The selection of material containing both partial resistance and disease tolerance traits was shown in one case to provide an inadvertent selection of tolerance over resistance traits (Mikaberidze and McDonald, 2020).…”