CHARACTERIZATION OF 2 EPIPHYTIC BACTERIA FROM SOYBEAN LEAVES WITH ANTAGONISTIC ACTIVITIES AGAINST PSEUDOMONAS-SYRINGAE PV GLYCINEA

The strains 48b/90 and 22d/93 are naturally occurring ephiphytes which were isolated from soybean leaves. On the basis of pheno- and genotyp ic characteristics 48b/90 was identified as Erwinia herbicola and 22d/ 93 as Pseudomonas syringae. These two isolates produced biological act ive substances against different indicator organisms. The E. herbicola strain showed clear antagonistic properties against Escherichia coli and Pseudomonas syringae pv. glycinea, but not against Geotrichum, can didum. 22d/93 was active against P. glycinea and G. candidum but not a gainst E. coli. Strain 48b/90 produced at least two different inhibito rs: an antibiotic substance and an inhibitor of the alginate synthesis . Strain 22d/93 produced at least three different compounds inhibitory to P. glycinea and one to G. candidum. Their activities against the b acterial blight pathogen, P. glycinea, can be observed in planta, too. Under the influences of the antagonists the pathogen multiplied at lo wer rates and to lower stationary phase population levels. The develop ment of bacterial blight symptoms was suppressed.