ИСТИНА

Bacteria produce a wide variety of secondary metabolites with miscellaneous biological functions. These metabolites are small molecules, e.g., non-proteinogenic amino acids and peptides, aldehydes, alcohols, esters, fatty acids, hydrocarbons, ketones and their derivatives in the form of volatile organic compounds (VOCs). The first database of microbial volatiles was created recently [1]. VOCs produced in the microbial world are ideal infochemicals because their spheres of actions include ‘aqueous’ as well as ‘atmospheric’ diffusion and consequently, these volatiles can act aboveground as well as belowground. The ecological functions of microbial VOCs are still under investigation. This study for the first time demonstrated the strong inhibitory effect of bacterial ketones taken at ecologically relevant concentrations on cyanobacterial photosynthesis in vivo [2]. Ketones cause significant disturbances in the photosynthetic apparatus of cyanobacteria during the first hour of incubation. These effects include (1) change of the induction curve shape, (2) increase of the chlorophyll and phycobilin fluorescent intensities compared to the control, and (3) prolonged dark recovery kinetics of the PSI and PSII reaction centers oxidized by a single light flash. Depending on the time of incubation, the action of ketones may be similar to that of known artificial inhibitors of PSII. After the third hour of incubation with ketones, significant chlorophyll degradation occurred. Our experimental data indicate disruption of photosynthetic electron transport and energy transfer from phycobilins and chlorophyll in the PSII reaction centers. Apparently, ketones as metaboliс products of a number of microorganisms can participate in antagonistic interactions in the environment. This work was partially supported by the Russian Foundation for Basic Research (grants 17-04-00412-a, 18-04-00375-a). References: 1. Marie Lemfack et al. (2017) Nucleic Acids Res. 46, pp.D1261-D1265. 2. Elena Voronova et al. (2019) J. Phycology. https://doi.org/10.1111/jpy.12861