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ARS Home » Research » Publications at this Location » Publication #69412
Title: POPULATION DYNAMICS OF THE BIOCONTROL AGENT ENTEROBACTER CLOACAE 501R3 AND THE CARBOHYDRATE-UTILIZATION MUTANT A-11 IN VARIOUS SPERMOSPHERES

Author
item YUCEL, IREM - VPI&SU, BLACKSBURG, VA
item Dery, Pierre
item Roberts, Daniel

Submitted to: Molecular Plant Microbe Interactions
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: NA.

Technical Abstract: Colonization of nutritionally-complex environments such as plant-soil interfaces by beneficial bacteria is of potential importance, but is poorly understood. Exudates from cucumber, pea, radish and sunflower seeds contained complex mixtures of carbohydrates and amino acids as determined by thin layer chromatography. Levels of carbohydrate, as determined by the anthrone assay, were at least 310-fold greater in pea exudate than in exudates from cucumber and radish. Moreover, levels of amino acid, as determined by the ninhydrin assay, were at least 130-fold greater in pea exudate than in exudates from cucumber and radish. Enterobacter cloacae 501R3 was capable of in vitro growth on all carbohydrates detected in these seed exudates within 8 hr. Strain A-11 was reduced or deficient in growth on 75% of the carbohydrates that supported the growth of strain 501R3 (Roberts et. al, 1992, Can. J. Microbiol. 38:1128-1134). Both strains had equivalent growth capabilities on all amino acids as well as on pyruvate and L-malate. Population levels of both E. cloacae strains were similar (P=0.05) at 24, 45, and 96 hr after the onset of germination in corn, pea, soybean and sunflower spermospheres when assays were performed in a natural gravely loamy sand field soil and in sterile sand. In contrast, growth by strain A-11 was significantly slower (P=0.05) than growth by strain 501R3 in cucumber and radish spermosphere over this 96 hr period in both the field soil and in sterile sand. The data indicate that the ability to utilize complex mixtures of carbohydrates increases ecological fitness in spermospheres with limited quantities of reduced carbon.