3.5 Dickeya solani exhibited a fitness advantage overD. dianthicola in hyacinths.
The symptom incidence and competition were further evaluated in hyacinths, that represent important hosts as they constitute a reservoir or/and primary or intermediate host of D. solani. We expected a higher symptom incidence and growth advantage of D. solani on hyacinth host as compared to D. dianthicola . The five D. dianthicola and five D. solani bacterial strains were inoculated separately on eight plants per strain and the number of symptomatic and asymptomatic plants were counted. At 61 dpi, a Kruskal-Wallis test revealed differences between D. solani and D. dianthicolain terms of symptom incidence (k=3.03; DF=1; p=0.08): D. solaniwas found more virulent than D. dianthicola ; means ± SE of the percentage of symptomatic plants reached 43% ± 17 and 23% ± 9, respectively (Figure S5a) .
In co-inoculation assays with species mixtures (Figure S5b ), the qPCR quantification of the pathogens in five symptomatic tissues showed that the calculated CI were different from one (Kruskal-Wallis test: k=7.8; DF=1; p= 5 x 10-3). The CI median value of 4 x 109 indicated a high competitive advantage ofD. solani over D. dianthicola in rotted tissues of hyacinths. Bulb plants thus appeared promoting competitive exclusion ofD. dianthicola by D. solani , which would lead to an enrichment in D. solani in the bulb plant agrosystems.