2.6 Statistical analyses
The slopes of the dynamics of the percentages of Dickeya -,Pectobacterium -, D. solani - and D. dianthicola -positive fields were analyzed using F-tests and ANCOVAs using GraphPad Prism version 8.4.2 for MacOS, GraphPad Software (www.graphpad.com). A Chi-squared method was used to test the non-random distribution of taxa in each field.
In all the plant assays, the non-inoculated plants and tubers remained asymptomatic, and this control condition was not considered in statistical analyses. The two symptom classes (with or without symptoms) of potato plants and hyacinths, the five symptom classes in tuber assays, and gene expression levels were compared among treatments (the different pathogens) by Kruskal-Wallis tests (α = 0.05) because the data significantly deviated from normality. Then, post-hoc Tukey tests were run to assess what pairwise differences were significant. When the bacterial strains were inoculated separately on plants and tubers, we compared the D. solani and D. dianthicola species traits using each bacterial strain as a replicate of the considered species. When the bacterial strains were inoculated altogether to constitute an experimental population, we compared the D. solani and D. dianthicola species traits using at least two independent replicates of the experiments.
In competition assays, the hypothesis of balanced abundances of the two competitors was tested by comparing the calculated CI values to one using a Kruskal-Wallis test. Analyses were carried out with the software R (http://www.R-project.org) using the packages RcmdR and nparcomp.