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Title: GENETIC ANALYSIS OF THE SEED COLONIZATION MUTANT ENTEROBACTER CLOACAE A-11

Author
item Roberts, Daniel
item Dery, Pierre
item YUCEL, I. - U.S. PATENT OFFICE
item Buyer, Jeffrey
item HOLTMAN, A. - RUTGERS UNIVERSITY
item KOBAYASHI, D. - RUTGERS UNIVERSITY

Submitted to: International Plant Growth Promoting Rhizobacteria Workshop
Publication Type: Proceedings
Publication Acceptance Date: 9/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Research was performed to determine the role of specific carbohydrates, produced by seeds and roots, as nutrients for the biocontrol bacterium Enterobacter cloacae during growth on plant surfaces in the soil. Growth (colonization) on plant surfaces is believed to be important for successful biocontrol. It was determined that the importance of these carbohydrates becomes more important during colonization of plant seeds and roots that d not produce as much carbohydrate or much of other nutrients such as amino acids or other organic acids. This information will be useful in determining under which environmental conditions E. Cloacae and other bacterial biocontrol agents will be most successful in suppressing infection by soilborne plant pathogenic fungi. This information will be useful to scientists.

Technical Abstract: Strain A-11, a transposon mini-Tn5 mutant of the bacterial biocontrol agent Enterobacter cloacae 501R3, is reduced or deficient in growth on most sugars that support growth of strain 501R3. Both strains A-11 and 501R3 have equivalent growth on all organic and amino acids tested. Genetic analysis of strain A-11 indicates that phosphofructose kinase, or another key enzyme(s)in carbohydrate metabolism, is inactivated by mini-Tn5 Km. Strain A-11 is reduced in colonization of cucumber but not pea spermosphere relative to strain 501R3. Both cucumber and pea seed exudate contain a number of different carbohydrates. However, pea seed exudate contains four and two orders of magnitude more carbohydrate and amino acid, respectively. The data reported here are consistent with our hypothesis that versatility with regard to carbohydrate nutrition is important under conditions where reduced carbon compounds are limited in the spermosphere.