The wild tomato species Solanum chilense shows local variation in pathogen resistance between geographically distinct populations
- Published
- Accepted
- Subject Areas
- Ecology, Evolutionary Studies, Plant Science
- Keywords
- Wild tomato, Phytopathology, Fusarium, Phytophthora, Alternaria, General Liniarised Mixed Models
- Copyright
- © 2016 Stam et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. The wild tomato species Solanum chilense shows local variation in pathogen resistance between geographically distinct populations. PeerJ Preprints 4:e2468v1 https://doi.org/10.7287/peerj.preprints.2468v1
Abstract
Wild tomatoes are a valuable source of disease resistance germplasm for tomato (Solanum lycopersicum) breeders. Many species are known to possess a certain degree of resistance against certain pathogens, however evolution of resistance traits is yet poorly understood. For some species, like Solanum chilense, both differences in habitat and within species genetic diversity is very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations of S. chilense. We investigate the phenotypic differences in disease resistance within S. chilense against three common tomato pathogens (Alternaria solani, Phytophthora infestans and a Fusarium sp.) and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that within S. chilense, resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Alternaria B055 infection
Infected fraction of seven S. chilense populations for Alternaria solani strain B055. The boxplots show the median and 1st and 3rd quartile of the infected fractions per leaf. The Y axis ranges from 0 (no infected leaflets on a leaf) to 1 (all leaflets show infection). On the X axis, each population is represented. The colours correspond to the geographic regions as depicted in figure 1.
Pairwise comparisons for all infection experiments
Results of Tukey's Honest Significant Differences test for pairwise comparisons between all populations for A) Alternaria B) Fusarium C) Phytophthora. The Y-axis indicates the individual comparisons, the X-axis shows the observed difference (vertical lines), with a 95% confidence interval (whiskers). Differences are considered significant if the whiskers do not cross the line at 0.
Summaries for GLMM
Summaries for Generalised Mixed Linear Models used in this study
Surface Sterilisation
Sterilisation of leaf surface area has moderate effects on infection of S. chilense.A. S. pennellii leaf, left washed with distilled water, right washed with 70% EtOH. B. Water (left), EtOH (right) washed of S. chilense LA4330 leaves.
