Project plan

The search for more efficient antagonistic strains against phytopathogens to support both the economic feasibility and practical efficiency of biocontrol methods is an ongoing process. The proposed project aims to identify and characterize new strains of A. pullulans or even new species of the genus Aureobasidium (for instance A. subglaciale) with improved tolerance to stress that can be used in biocontrol of selected plant pathogens.

This will be achieved by exploiting the rich resources of the EX Culture Collection, which contains numerous strains of Aureobasidium spp. from various environments (moderate climate plants from local environment, plants from salterns in the Mediterranean, from Artic glacial ice etc).

This collection of Aureobasidium spp. strains will be screened for antagonistic effects on selected plant pathogens (fungal and bacterial) in vitro and in situ. We will identify strains that are more stress tolerant (to low and high temperatures, drought, salts and UV irradiation) than commercially available strains presently used for biocontrol.

The genomes of the selected strains with promising biocontrol potential will be re-sequenced by next-generation sequencing (NGS). The generated data will be subjected to the appropriate analysis to uncover traits relevant to the biocontrol. The basis of the mechanism for bacterial or fungal antagonism will be addressed by screening their enzymatic activity, production of siderophores or other compounds such as volatile organic compounds.

Finally we will develop the real-time polymerase chain reaction (PCR)-based method for molecular detection of the strain of Aureobasidium with the best potential for use in the biocontrol. The method will discriminate between the introduced and indigenous Aureobasidium strains.

Based on gained results, we will evaluate the possibility of using new strains of Aureobasidium spp. for biocontrol against certain plant pathogens before and after harvest, either individually or in combinations of various strains.

The project consists of 4 work packages (WPs), three of which include scientific research, whereas the forth WP comprises the project management and knowledge dissemination. Each WP comprises up to five tasks (T), which are described below.

WP1: Screening of a collection of Aureobasidium spp. strains for antagonism

Screening of antagonism of Aureobasidium spp. strains (A. pullulans and A. subglaciale) from the EX Culture Collection (Mycosmo) and commercially used biocontrol strains against the selected fungal and bacterial phytopathogens in vitro (on nutrient media) and in situ (on fruits or detached blossoms) under relevant stressful conditions.

The antagonism to the following plant pathogens will be tested on three postharvest fungal pathogens, namely Penicillium expansum (blue mold), Botrytis cinerea (grey mold), Colleotrichum acutatum (bitter rot) and one preharvest bacterial pathogen Erwinia amylovora, the causative agent of fire blight.

T1.1 The first screening or in vitro antagonism to selected plant pathogens

The collection of Aureobasidium strains will be evaluated for their interactions with P. expansum, B. cinerea, and C. acutatum in culture according to previously employed procedure (Mari et al., 2012b). The strains with distinguishable antagonism towards tested pathogens will be further evaluated for their biocontrol potential under stressful conditions. Finally, the list of Aureobasidium spp. strains will be prepared and used in the second screening.

T1.2 The second screening or in situ antagonism to selected plant pathogens

In the second screening the selected strains with in vitro antagonistic potential will be used for the evaluation of in situ antagonistic activity; for postharvest fungal pathogens on apples and for bacteria E. amylovora on detached apple blossoms.

Milestone 1: The list of Aureobasidium spp. strains with the best antagonistic activity in vitro and in situ


WP2: Phenotypic and genotypic characterisation of selected Aureobasidium spp. strains

WP2A Phenotypic characterisation of selected Aureobasidium spp.

T2.1 Extracellular enzymes production

T2.2 Iron depletion or siderophore production

T2.3 Production of inhibitory volatile organic compounds

Milestone 2: Phenotypic characterization of the selected Aureobasidium spp. will be completed.

WP2B Genotypic characterisation of selected Aureobasidium spp.

T2.4 Genome sequencing and assembly

T2.5 Genome analysis for traits related to the biocontrol

Milestone 3: Completed genotypic characterization of the selected Aureobasidium spp..


WP3: Development of the method for the detection and quantification of the specific Aureobasidium spp.

T3.1 Development of the method for the detection and quantification of specific Aureobasidium spp.

Milestone 4: Method for detection and quantification of specific Aureobasidium spp. developed.


DS4: Project management and dissemination of knowledge

T4.1 Supervision of the work, evaluation of results and delivery of milestones.

T4.2 Dissemination of knowledge.

Milestone 5: The data obtained during the project are published.