Summary of potential virulence mechanisms of tested strains and their association with nematode killing.

a. B. ceno  =  B.cenocepacia; B. cep  =  B.cepacia; B. mult  =  B. multivorans; B. amb  =  B. ambifaria, P. aerug  =  P. aeruginosa.
b. Liquid killing  =  mean percentage of nematodes killed by ∼120 h, ± SEM (n = 3). Burkholderia strains vary significantly in lethality, F = 155.3, p<0.0001.
c. PGS agar killing  =  mean percentage of nematodes killed by 48 h on high-osmolarity PGS agar; ± SEM, (n = 3) --  =  not determined. Burkholderia strains vary significantly in lethality, F = 36.57 p<0.0001.
d. Toxin-mediated killing  =  mean percentage of nematodes killed by a toxin secreted by the test strain after 24 h; the toxin traversed a filter and was localized in agar. (± SEM, n = 3). nd  =  not determined. Burkholderia strains vary significantly in lethality, F = 129.2 p<0.0001.
e. Protease production  =  mm of clearing beyond colony growth after 40 h on milk agar. Readings were identical from three replicates, which prevents analysis of variance.
f. Swarming motility  =  mean mm of surface migration beyond the dense zone of swimming motility on 0.35% T-Soy agar after 24 h, (± SEM, n = 3). Motility varies significantly among Burkholderia strains: F = 53.8, p<.0001.
g. C8-HSL production  =  GFP emission at 514 nm following excitation at 475 nm of pAS-C8 in P. putida F117, scaled for OD600 of the log-phase Bcc culture prior to extracting its supernatant. Numbers are fold-increases over E. coli OP50, the negative control (mean ± SE, n = 6). Readings varied significantly among Burkholderia strains: F = 338, p<0.0001.
h. Supernatant attraction  =  ratio of worms (mean ± SE, n = 3) found near droplet of supernatant of test strain relative to that of E. coli following 1 h of incubation. Supernatants from different strains varied in their attractiveness, F = 7.37, p = 0.001.