Dynamics of abundance of antifungal strains of Pseudomonas in the rhizosphere of hydroponic cucumbers grown on greenhouse mineral substrate

Data were obtained on the dynamics of the abundance of the biocontrol strains of Pseudomonas chlororaphis SPB1217 and Pseudomonas fluorescens SPB2137 with antifungal activity. These strains are able to develop in the rhizosphere of cucumbers grown on mineral substrate under hydroponic conditions in industrial greenhouses. After four weeks of vegetation of plants, the abundance of the inoculated strains was 19–28% of the total bacterial numbers determined by inoculation onto solid medium. The investigated strains spread together with the young, actively growing and exudating roots; they reached a stable level of abundance in deep layers of the greenhouse substrate. A significant difference in the abundance of fungi in the tested variants was observed after 20 days of vegetation: the abundance of fungi in the control was two times higher than in the variant inoculated with strain SPB2137.