Induction of Barley Resistance to Fusarium graminearum by Application of Bacterial Consortium with Agronomic Traits

The aim of this study is to develop and comprehensively evaluate the efficacy of an innovative formulation of a biological preparation consisting of a bacterial consortium (Serratia proteamaculans B5, Pseudomonas putida D7 and Lysinibacillus sp. S1), embedded in a pullulan polysaccharide matrix, as an agent for inducing systemic resistance in barley (Hordeum vulgare L.) to phytopathogenic stress caused by Fusarium graminearum. To optimize the product’s protective efficacy and minimize the pesticide load on the agroecosystem, a reduced dose of Fundazol (50% of the standard rate) was incorporated into the formulation. The constituent strains exhibited high indole-3-acetic acid production (53.29–69.2 μg·mL−1) and strong antagonistic activity against phytopathogenic fungi, with inhibition zones reaching up to 32.5 mm. Pot and field trials were conducted to comprehensively assess the effect of the biological product on the stress tolerance of barley plants. Pre-sowing seed treatment reduced proline accumulation (by up to 2.3-fold), maintained photosynthetic pigment levels, and increased field germination to 79%. Under infectious field conditions, treatment with the biopreparation contributed to the stabilization of yield structure parameters (treated plants exhibited increases in height and biomass of 9–21%) and the improvement of grain quality indicators. Overall, the results obtained demonstrate the potential of the developed biopreparation as a component of comprehensive protection strategies and as an inducer of plant priming mechanisms.