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ARS Home » Research » Publications at this Location » Publication #74681
Title: USE OF A COLONIZATION-DEFICIENT STRAIN OF ENTEROBACTER CLOACAE IN STRAIN COMBINATIONS FOR ENHANCED BIOCONTROL OF CUCUMBER SEEDLING DISEASES

Author
item Roberts, Daniel
item Dery, Pierre
item Mao, Weili
item HEBBAR, PRAKASH - OICD

Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Inconsistent suppression of soilborne diseases by plant-beneficial bacterial has limited their commercialization. Approaches must be developed to over come this inconsistent performance. In this report we show that combinations of the plant-beneficial bacteria, Enterobacter cloacae A-46 and Burkholderia cepacia Bc-B in cucumber seed treatments, provide more consistent suppression of cucumber seed and seedling pathogen than seed treatments containing individual bacterial strains. We also demonstrate that cucumber root colonization by E. cloacae is not required for this improved biocontrol performance. This information will be useful to scientists.

Technical Abstract: Colonization of cucumber roots by Enterobacter cloacae A-46, a transposon mini-Tn5 Km mutant of E. cloacae 501R3, was limited to the uppermost centimeter of root. Populations of strain A-46 were significantly lower than those of strain 501R3 on all root sections. Seed treatments containing combinations of strain A-46 and Burkholderia cepacia strain Bc-B Bprovided significantly greater (P equal to 0.05) disease suppression of cucumber seedling pathogens in a field soil naturally infested with Pythium and Fusarium spp. than seeds treated individually with strains Bc-B, A-46, or 501R3. Although strain A-46 had no effect on disease severity, it enhanced the biocontrol effectiveness of strain Bc-B. Seed treatments containing combinations of strains 501R3 and Bc-B were similar to seed treatments containing Bc-B only. The results indicate that rhizosphere colonization by E. cloacae is not required for biocontrol performance of treatments containing E. cloacae and B. cepacia. In addition, it may be advantageous to use rhizosphere-colonization-deficient strains of E. cloacae in seed treatments in combination with B. cepacia.