Anais do Congresso Paranaense de Microbiologia
IV Congress of Microbiology in Paraná

The agricultural market continues to grow in Brazil, moving over 1 trillion reais in the last year. Considering the need to use agricultural pesticides, for the good development and production of plants, new alternatives are sought, that are less aggressive to the environment and proportionally effective when compared to chemical-synthetic pesticides for the control of phytopathogens. Bacillus genus bacteria have been studied for this purpose due to their ability to produce antimicrobial molecules, as well as their ability to colonize the rhizosphere. The bacterial establishment in the rhizosphere is fundamental for the interaction between the microorganism and the plant to occur, when this interaction is beneficial, it creates a barrier, hindering the growth of phytopathogenic fungi. The aim of this study was to evaluate in silico and in vitro the swarming and biofilm formation capacity of the strain called Bacillus velezensis Labim 44 (L44), which, due to its antifungal activity, demonstrate as a potential agent of microbiological control. In the in silico test, a MULTIFasta file containing 50 genes related to biofilm formation and swarming capacity was used. This file was compared against the entire genome of L44 using the BLAST program, and the evaluation was carried out using similarity data between genes and the bacterial genome. For in vitro evaluation of Swarming, the inoculum was transferred to an 85mm petri dish containing semi-solidified Tryptic Soy Agar medium (0.8%), a 10 µL aliquot of the inoculum adjusted in saline solution using the tube 0.5 of McFarland scale was added to the center of the plate, which was then incubated at 28ºC for 24 hours. For the in vitro analysis of Biofilm, 24-well microplate containing Tryptic Soy Broth medium were used, 10 µL of inoculum on the same characteristics added to the wells and the plate incubated for 48 hours. Comparative analyzes showed similarities in 41 genes with percentage identity ranging between 75.1% and 100%. It was confirmed in vitro that the L44 is capable of swarming motility, being able to colonize the entire plate after 16 hours of incubation. A biofilm formation capacity by the strain after incubation was also affirmed. The obtained results suggests that the target genes of this study are present giving the colonization and motility capacity, important for the rhizospheric colonization process by microorganisms.