Influence of Nitrogen Source on 2,4-diacetylphloroglucinol Production by the Biocontrol Strain Pf-5

Hultberg M*, Alsanius B
Department of Horticulture, Microbial Horticultural Laboratory, Swedish University of Agricultural Sciences, Alnarp, Sweden

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© Hultberg and Alsanius; Licensee Bentham Open

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.

* Address correspondence to this author at the Department of Horticulture, Swedish University of Agricultural Sciences, P.O. Box 44, SE 230 53 Alnarp, Sweden; Tel: +46+40415325; Fax: +46+40460557; E-mail:


The production of 2,4-diacetylphloroglucinol (DAPG) by the biocontrol agent Pseudomonas fluorescens Pf-5 was studied in nutrient-solution based media with varying nitrogen content. No production of DAPG was observed when organic nitrogen was omitted from the media, regardless of the inorganic nitrogen source used. Furthermore, a micromolar concentration range of organic nitrogen was insufficient to sustain production. When a millimolar concentration range of organic nitrogen was used, DAPG production was observed in the medium with ammonium as the inorganic nitrogen source. No production was observed in the treatments with ammonium and nitrate or nitrate only, despite growth of the bacterial strain being the same for all treatments. These results suggest that it is possible to manipulate the nutrient solution to increase the reliability and efficacy of biological control agents.

Key Words: Biological control, 2, 4-diacetylphloroglucinol, greenhouse, nitrogen source, Pseudomonas fluorescens Pf-5.