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.