title: The adaptive potential of a plant pathogenic fungus, Rhizoctonia solani AG-3, under heat and fungicide stress.
abstract: The ability to improve fitness via adaptive evolution may be affected by environmental change. We tested this hypothesis in an in vitro experiment with the plant pathogen Rhizoctonia solani Anastomosis Group 3 (AG-3), assessing genetic and environmental variances under two temperatures (optimal and higher than optimal) and three fungicide concentrations (no fungicide, low and high concentration of a copper-based fungicide). We measured the mean daily growth rate, the coefficient of variation for genotypic (I (G)) and environmental variance (I (E)) in growth, and broad-sense heritability in growth. Both higher temperature and increased fungicide concentration caused a decline in growth, confirming their potential as stressors for the pathogen. All types of standardized variances in growth-I (G), phenotypic variance, and I (E) as a trend-increased with elevated stress. However, heritability was not significantly higher under enhanced stress because the increase in I (G) was counterbalanced by somewhat increased I (E). The results illustrate that predictions for adaptation under environmental stress may depend on the type of short-term evolvability measure. Because mycelial growth is linked to fitness, I (G) reflects short-term evolvability better than heritability, and it indicates that the evolutionary potential of R. solani is positively affected by stress.
authors.affiliation: Institute of Integrative Biology, Plant Pathology, ETH Zürich, 8092 Zürich, Switzerland. yvonne.willi@unine.ch
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Willi
authors.forename: Aline
authors.initials: A
authors.lastname: Frank
authors.forename: Renate
authors.initials: R
authors.lastname: Heinzelmann
authors.forename: Andrea
authors.initials: A
authors.lastname: Kälin
authors.forename: Lena
authors.initials: L
authors.lastname: Spalinger
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Ceresini
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000704:Analysis of Variance; D005075:Biological Evolution; D003300:Copper / Q000494:pharmacology*; D025141:Drug Resistance, Fungal; D004777:Environment; D005659:Fungicides, Industrial / Q000494:pharmacology*; D014644:Genetic Variation / Q000187:drug effects; D005838:Genotype; D006358:Hot Temperature; D025301:Hyphae / Q000187:drug effects / Q000254:growth & development; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D012232:Rhizoctonia / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013312:Stress, Physiological / Q000187:drug effects; D013557:Switzerland
chemical_list: D005659:Fungicides, Industrial; C007120:copper oxychloride; D003300:Copper