Optimization of Growing Medium and Preservation Methods for Plant Beneficial Bacteria, and Formulating a Microbial Biopreparation for Raspberry Naturalization

Abstract

The current study focuses on the optimization of bacterial growing medium composition, including the carbon and nitrogen source in different concentrations, the pH value of the medium and the temperature. Optimization was performed for four environmental bacterial isolates belonging to the genera Arthrobacter, Pseudomonas and Rhodococcus, which were previously obtained from wild raspberries. These bacteria proved to be potent antagonists against certain fungal and fungal-like plant pathogens. Furthermore, three preservation methods and three sample preparation techniques were evaluated. In addition, a prebiotic supplementary blend based on previous research was tested. The research included a pot experiment to estimate the influence of bacterial cultures on the growth of plant shoots and roots, on the soil enzymatic activity and the content of macronutrients, minerals and nitrogen in the soil depending on the naturalization strategy. The best carbon and nitrogen source were chosen. The addition of a supplementary blend resulted in the increased growth of two bacterial isolates. Bacterial inoculum applied to the roots and watering resulted in increased shoot mass in objects infected with plant pathogens, although in plants without the pathogen infection, bacterial inoculum resulted in the decreased mass of plants. Naturalization strategy should be matched to the pathogens present at plantations.

Selection of redox dye and inoculum conditions for the optimisation of respirometric indices in <i>Verticillium</i> and <i>Trichoderma</i>

“…Nitrogen strongly impacts fungal species' competitiveness in several ecological niches (Band et al, 2022). A tailored supplementation with carbon substrates was recently proposed to improve the effects of biocontrol preparations based on antagonistic bacteria (Pylak et al, 2021) or fungi . These substrates are selected to positively affect antagonistic fungi included in biopreparations to implement their efficacy against plant pathogens' activity.…”

“…The Phenotype MicroArray TM system (PM) can be efficiently applied to study the differential fungal use of substrates as carbon or nitrogen sources. It is a sensitive, reliable, and repeatable method based on functional fingerprinting (Cruz-Magalhaes et al, 2022) that also finds application in prebiotic supplement selection Pylak et al, 2021). However, carbon source-based panels have been more widely used, while nitrogen-based screening has been much less exploited, even though nitrogen is an essential element, especially in trophic competition among species (Maynard et al, 2017).…”