These results were presented as an invited lecture of the project leader on Slovenian microbiological society conference in the section Microbes and environment in Bled. Recently, we have shown that B. subtilis strains, which were isolated from the soil microscale, are capable of kin discrimination during swarming on a semi-solid medium. Swarms of kin strains merged on semi solid medium, while a border line was formed between two non-kin swarms. Biofilm formation on plant root reveals mixed biofilms of kin strains while only one of the strains prevailed in the biofilm when two non-kin strains were inoculated. Similarly, a common swarm was observed when two kin strains were spotted on the agar surface, while in the mixture of two non-kin swarms on the semi-solid medium one dominated and spread over the whole surface of the plate. Electronic microscopy revealed damaged cells between two non-kin swarms, while the cells were undamaged and intact at the point of kin-strain merging. Increased transformation frequency was observed on the border line, which means that the exchange of DNA was more frequent among non-kin strains than between kin strains. These discoveries reveal the interactions of highly related B. subtilis bacteria, their sociality, and the consequences of such interactions on survival and the evolution of this species.
COBISS.SI-ID: 4824184
These results were presented as a lecture of the project leader at the 6th ASM conference on Cell-cell communication in Athens, Georgia, USA. This the most prestigious conference on microbial communication that is held every three years and it is a success and honor to be chosen for an oral presentation and indicates that the work performed within this projects is perceived internationally as important and of interest to a broader audience. The lecture was based on hypothesis that kin discrimination is a form of communication, which provides the means to cooperate with kin. Our results indeed indicate that kin strains are able to perform cooperative swarming while non-kin strains segregate and compete. In addition, a novel findings on the role of kin discrimination in horizontal gene transfer was presented and its potential role in the genome dynamics of the species discussed.
COBISS.SI-ID: 4855416
Young project leader, dr. Štefanič presented her work as a lecture at the international congress in Berlin, the 19th International Conference on Bacilli & Gram-Positive Bacteria, which is the most important meeting of experts who use bacteria from the genus Bacillus as a model organism in their research. The lecture was very remarkable, and dr. Štefanič was awarded the Best Speaker Award, which is an exceptional success. In the course of the lecture, she presented past and present results in the field of kin discrimination and the assumption that antagonism between the strains is a key issue in this phenomenon. This hypothesis was supported by various experimental results on the topics 1) competition of kin and non-kin strains on plant roots, 2) investigation of the borderline and cell lineage with an electron microscope, 3) testing of the ability of bacterial sporulation on the border line, 4) DNA transfer and transcription of competence genes. Experiments have shown that swarms of mixed kin strains forms a mixed biofilm on the root, while the biofilm consists of one strain when two non-kin strains are inoculated simultaneously. Electron microscopy on the border line showed lysed and damaged cells, while the cells in the swarms were healthy. Sporulation as a survival strategy at the borderline showed that the sporulation of one non-kin strain is significantly lower compared to the sporulation of the same strain in combination with the kin strain. At the borderline, an increased transfer of DNA among non-kin strains was observed.
COBISS.SI-ID: 4800120