Fig. 1: Analysis of D. discoideum natural isolate growth on different bacterial prey.

a Schematic of growth competition assay of natural strains. Natural isolates and the reference strain AX2-GFP were initially grown up clonally. Each natural isolate was then mixed with AX2-GFP at a starting ratio of 1:1 and plated onto an SM plate with bacterial prey as a food source. The starting frequencies of the two strains were determined by flow cytometry. Mixtures of strains were grown in competition for 48 h (~10 generations of growth) and the relative proportion of labelled and unlabelled cells was determined by flow cytometry. b Growth of D. discoideum natural isolates compared to AX2-GFP on K. aerogenes. Growth rates are relative to the AX2-GFP control. Horizontal lines within the boxes indicate median values, the boxes the interquartile range, whiskers show the smallest and largest values within 1.5 times the interquartile ranges above and below the 75th and 25th percentile, and dots represent outliers from these ranges. Competitions were performed between 4 and 23 times for each of the 24 wild D. discoideum strains (median n = 11). c Frequent switches in competitive performance occur across different prey types. Relative growth rates for a representative subset of eight natural isolates were determined on six bacterial prey: K. aerogenes (Ka), B. subtilis (Bs), E. coli (Ec), K. pnuemoniae (Kp), M. luteus (Ml), and P. aeruginosa (Pa), and then ranked (1 = best performer, 8 = worst) based on their “win-loss” record (in terms of significant differences in growth) when compared to each other strain on a given bacteria (see ‘Methods’ section). Each line shows the ranking of one of the eight different D. discoideum strains across all six bacterial prey types, with lines frequently crossing one another illustrating the frequent significant switches in performance ranking on different bacterial prey. At least three independent biological replicates were performed for each D. discoideum strain/bacterial prey combination competition. Source data are provided in the Source Data file.