Figure 1.
Phylogeny of the Sclerotiniaceae inferred from 3 housekeeping loci showing incongruencies with pathogenicity-related genes trees, and results of acid production on indicator plates.
A. Housekeeping gene phylogeny of the Sclerotiniaceae from the concatenated sequence of hsp60, g3pdh and cal. The putative obligate biotroph, Ciborinia whetzelii, was added based on the placement of Holst-Jensen et al. [52]. Thick branches represent well-supported nodes with >90% support from 1000 maximum likelihood (ML) bootstrapped pseudoreplicates and >0.95 posterior probabilities. An asterisk represents the node with >75% ML bootstrap support and >0.90 posterior probabilities. Trophic type is designated by text color: necrotrophs in red, biotrophs in green, and taxa with unknown life histories in black. B. Incongruence between the housekeeping gene phylogeny in Figure 1A and the phylogeny of each pathogenicity-related gene (acp1, asps, pg1, pg3, pg5, pg6, pac1, oah). Horizontally aligned with the housekeeping phylogeny, red fill designates a species incongruent with respect to the gene indicated at the top of the column and the housekeeping phylogeny; grey fill indicates congruence; white fill represents a gene that failed to amplify with the primers employed. C. Results from bromophenol blue plates indicating acid production as a proxy for oxalic acid production at two time points: 72 hours post-plating, and a final time point if acid production was delayed. Purple fill represents no color change indicating no acid production or production below the limit for detection, bright yellow fill represents a strong color change qualitatively indicating higher production, and a light yellow fill represents a less intense color change. Isolates not tested are n/a.
Table 1.
Site-specific likelihood analyses for eight pathogenicity-related genes and two housekeeping genes.
Table 2.
Branch-specific likelihood analyses for lineage comparisons.
Figure 2.
Relative virulence of fungal strains on detached Arabidopsis thaliana leaves.
Disease lesions were measured as a percentage of total leaf area at 16, 24, 48, 72 and 96 hours post-inoculation using ImageJ. Error bars on both graphs represent the standard deviation among 3 biological replicates. Necrotrophic host generalists are shown in warm colors (reds and oranges), while necrotrophic and biotrophic host specialists are shown in cool colors (blues and greens, respectively). Strains that did not produce disease lesions on A. thaliana (Monilinia aucupariae, Monilinia fructicola, S. glacialis, and Sclerotium cepivorum) are not shown.
Figure 3.
In planta normalized oah transcript copy number at sampling times 1, 2, 4, 8, 12, 24, 48 and 72 hours post-inoculation.
All oah gene expression values are represented normalized to the housekeeping gene, actin. Error bars on both graphs represent the standard error among 3 biological replicates. Asterisks represent values that are significantly different using a split plot factorial repeated measures analysis. A. The first trial included the necrotrophic generalists, Botrytis cinerea and Sclerotinia sclerotiorum, a host specialist of unknown trophic type, S. glacialis, and the biotrophic specialists, Myriosclerotinia scirpicola and Myriosclerotinia duriaeana. B. The second trial included the necrotrophic generalists, Botrytis cinerea and Sclerotinia sclerotiorum, the necrotrophic specialists, B. tulipae, Monilinia fructicola, and Monilinia aucupariae, and the biotrophic specialist, Myriosclerotinia curreyana.