The role of volatile metabolites in microbial communities of the LSS higher plant link

Abstract

The paper addresses the possibility of controlling the microbial community composition through metabolites produced by microbes. The comparative analysis of experimental data has shown that volatile metabolites make a much greater contribution to the microbial interactions than nonvolatile ones. It has been found that interaction of microorganisms via the volatiles they release occurs frequently and is typical of a number of microorganisms. Volatile metabolites released by microorganisms produce an inhibitory, sometimes bactericidal, effect on the vital functions of bacteria. The stimulating action occurs 6–8 times less frequently. The range of action on the growth of the test cultures and the range of sensitivity to the effect of volatile metabolites of the study microbes have been found to be individual. Comparative cluster analysis of the ranges of action of 100 study cultures has shown that in the investigated set of microorganism species interaction was performed via a set of volatiles of an inhibiting action (82) and of a stimulating action (52). It has been found that release of volatile metabolites by the studied microorganisms depends upon the culture age, concentrations of components of the nutrient medium, and volatile by-products released by other microorganisms. This production can be increased or decreased by the action of volatile metabolites of other microbes. This is related to strain features and culture age. The prospects of using these regulating metabolites depend on the “range”, specificity and safety for other members of the microbial community in insufficient concentrations. Volatiles produced by plants and microorganisms as well as by other components of the system – humans and processing equipment installed inside the closed ecosystem – could influence the formation not only of the microbial community but also of the gas composition of the system’s atmosphere, through which they could affect the state of the plants. Specially performed experiments have shown that volatile metabolites of microorganisms can accumulate in their habitat, dissolve in the atmospheric water, and maintain their biological activity for days. It has been determined that volatile metabolites of some microorganisms are toxic for plants. Growth of seedling roots is inhibited more than growth of stems.