Within the SolACE project, different microbial consortia were selected to be tested in potato and wheat trials under combined drought and nutrient stresses. Using the Minigran® technology, SolACE partner DCM (a plant care company which develops, produces and markets biofertilisers, biostimulants and biopesticides) succeeded in designing a flexible formulation. The different microbial consortia are inoculated onto a small organic granule (between 1 and 2 mm in size), which can be easily adapted to different micro-organisms (Fig. 1).
For potato, three different consortia were selected to be used in field trials. All three consortia consist of a mixture of different gram negative bacteria, arbuscular mycorrhizal fungi and a Trichoderma fungus.
In spring 2019, project partners carried out potato field trials in three different locations: Agroscope in Switzerland, ÖMKi in Hungary and the University of Newcastle in the UK (Fig. 2). In the field trials in Switzerland and Hungary, three different microbial consortia formulated with the Minigran® technology were applied during the planting of potato tubers, and the effect of these microbial formulations on the stress resilience to nitrogen/phosphorus and water shortage was analysed. In the UK, one consortium was tested.
Following these field trials (Fig. 3), Agroscope has shown great interest in testing these Minigran® formulations again in supplementary glasshouse or field trials. While experimental details remain to be determined, Agroscope is interested in looking at the establishment of these different microbial consortia in the root system of potatoes.
Since the Minigran® formulation is based on organic raw materials, which have shown superior performance in supporting the establishment of plant-beneficial interactions with various plant growth promoting microbial (PGPM) inoculants in previous projects (Fig. 4), the new PGPM Minigran® formulations will also be tested in controlled drought stress experiments under greenhouse conditions at the University of Hohenheim. These experiments will assess the performance of the Minigran® formulations as potential nursery inoculants in potato, conduct inoculant tracing, and evaluate plant performance and physiological stress indicators. The results will also be compared with the conventional formulations tested so far.
To support these activities, DCM will develop specific molecular primers for the detection of the Trichoderma strain used in one of the consortia that is being evaluated in the SolACE project. In this way, the Trichoderma strain can be detected in the field, which makes it possible to link the presence of the strain with possible beneficial results.