The Multiple Activities and the Plant Beneficial Potential of Bacillus spp. Derived from the Permafrost of Western Siberia

Agents of biological control are an important part of traditional agriculture, as well as organic farming. However, in the climatic conditions of countries that are located in cold and temperate regions, plant protection requires particular biocontrol agents that have adapted to environments with low and unstable temperatures. This work presents the biocontrol potential and plant-promoting activity of Bacillus spp. that was isolated from permafrost sediments in Western Siberia. It was found that all of the studied strains (n = 10) were able to produce indole-3-acetic acid (IAA) and chitinolytic enzymes at low positive temperatures (5 °C). The antifungal activity of cold-tolerant bacilli against Microdochium sp., Fusarium spp., and Alternaria sp was recorded. In greenhouse and field conditions, the selected strains (B. simplex 948P-1 (IAA-producing) and B. megaterium 312 (with antifungal activity)) were assessed in comparison to a commercially available fungicide (tebuconazole) and biofungicide (B.subtilis 26D). It was found that the bacilli in the seed germination assay exhibited low phytotoxicity and there was no significant advantage over the conventional fungicides in the yield stimulation assay. However, the twin consortia of B. megaterium 312 and B. simplex 948P-1 was able to increase winter wheat yields by 50% (compared to the untreated group), and by 70% (compared to the commercial biofungicide-treated group). Moreover, applying the twin consortia of Bacillus spp. significantly reduced the infection rate of Fusarium spp. in first-generation wheat grain.