ИСТИНА

Microbiological cultures can undergo microevolution in laboratory conditions. Comprehensive study of this process is important not only from fundamental point of view, but it could help successfully adapt natural and genetically modified strains to specific or stressful conditions of industrial cultivation, that may be quite different in comparison with their natural habitats. In the present study we observed genetic and phenotypic changes in ascomycetous fungus Podospora anserina grown at aerated liquid media more then 5 years by serial passages. P. anserina is coprophilous fungus living in nature on dung of herbivores. Two initial strains were derived from individual mononuclear ascospores and became original for eight independent subcultures. Experimental conditions influenced dramatically on fungal morphology as well as on sexual reproduction, but constantly support unlimited vegetative growth of mycelium. All subcultures being removed on agar medium at any time, as well as on dung agar, grow with the same rate as wild type strains. Method of next generation sequencing for whole genome analysis lets us revealed 142 point mutations fixed in experimental subcultures in total after 268 passages in liquid: 52 of them were identified as missense mutations, 8 as nonsense, and 10 as frameshifts. Moreover, we have observed some examples of parallel evolution, the most impressive of which was the gene coding GTPase subunit alpha that was subjected to mutation fixation independently in seven subcultures. Functional annotation of found mutations indicates that some of them might be adaptive. The reported study was supported by RFBR, research project No. 16-04-01845 a