CROP SPECIFICITY OF RHIZOSPHERE PSEUDOMONADS AND THE INVOLVEMENT OF ROOT AGGLUTININS

Crop specificity of rhizosphere-inhabiting fluorescent Pseudomonas spp was studied for potato, grass and wheat grown in a silty loam soil. F or each crop about 50 dominant Pseudomonas isolates were obtained from the rhizosphere. Isolates were distinguished by comparing their lipop olysaccharide (LPS) and cell envelope protein (CEP) patterns About 30 distinct patterns were detected for each crop. The majority of LPS and CEP patterns observed for each crop was not detected on the other cro ps, suggesting a crop specificity for certain Pseudomonas populations. From each crop distinct Pseudomonas isolates were used to study crop- specific root colonization by growing potato, grass and wheat plants i n soil bacterized with a mixture of these isolates of the three crops. Crop specificity in root colonization could not be demonstrated. The involvement of root agglutinins in the composition of rhizosphere Pseu domonas populations was examined. Reactions of distinct Pseudomonas is olates from each crop with crude or partially-purified agglutinin prep arations of potato, grass or wheat did not correlate. We concluded tha t the composition of rhizosphere Pseudomonas populations differed betw een crops. However, crop-specific root colonization or crop-specific a gglutination could not be demonstrated with the experimental approach used.