BioMatNet Item: FAIR-CT96-1373 - Improvement of biological seed treatments against damping-off in crop production

FAIR-CT96-1373
Improvement of biological seed treatments against damping-off in crop production

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Biotechnology : FAIR Area 4.4.1 - Plant Health : Integrated Crop Protection & Biological Control

	Proposal No:	FAIR-CT96-1373
	Date Prepared:	January 1998
	Source:	Proposal Abstract

Abstract:
Seedling damping-off caused by soil-borne fungal pathogens results in persistent commercial losses in agriculture and horticulture. Seed treatment with antagonistic bacteria or fungi is an alternative to fungicides in the control of damping-off. However, under commercial conditions, biological treatments frequently show more variable activity than fungicides. The activity of biological seed treatments relies on efficient colonisation and metabolic activity of antagonists in the spermosphere and rhizosphere. Failure to colonise and poor biocontrol activity was frequently linked to:

competition from the indigenous soil microflora
susceptibility of biocontrol agents to adverse environmental conditions (soil moisture, pH, temperature, soil types etc.)
lack of appropriate seed coating technology for biologicals.

The main aim of the project is to use molecular approaches together with established soil microbiological methods to develop strategies that improve the efficacy of biological seed inoculation. This aim will be achieved through academic and industrial research and subsequent field evaluation.

Academic research Transforming bacterial antagonists with the luxAB reporter genes (Objective 1.) will allow accurate study of the fate of seed inocula in the soil environment. Use of lu7c marked strains of biocontrol agents will enable to determination of their environmental activity profiles (Objective 2.). These profiles facilitate design of antagonist combinations that extend biocontrol activity to a wider range of environmental conditions. Lux-marked antagonists and Tn5 mutagenesis will be used to identify the physiological characteristics (eg. catabolic activity range, motility, adhesion properties and siderophore and anti-microbial production) that contribute to rhizosphere competence (Objective 3.) of biocontrol agents. This information will be used to develop seed coat formulations and additives that improve rhizosphere competence of bacterial seed inocula (Objective 4.). Since individual antagonist treatments can rarely provide activity against all damping-offpathogens it is proposed to identify combinations of antagonists with synergistic modes of action (Objective 5.) and to integrate biological with fungicide seed treatments (Objective 6.).

Industrial research Strategies to improved biocontrol activity developed under Objectives 2 to 6 (eg mixed inocula, addition of carbohydrates and other seed additives) require the development of appropriate fermentation, formulation and seed coating methods. Two industrial partners (specialising in the production of microbial inocula and seed production/treatment) will therefore apply the fundamental data produced to improve and adapt fermentation technologies (Objective 7.) and seed coating and formulation methods (Objective 8.) for the different bacterial antagonists.

Field trials throughout the EU (Objective 9.) are proposed to evaluate the activity of biological seed inocula under different climatic and soil conditions and cultural production methods and to build confidence in both the scientific and user community in biological/integrated disease control.

Contacts

Coordinator

University of Aberdeen Dept of Plant and Soil Science / UNITED KINGDOM

Participant