Pseudomonas soli str. VMAP1: BACTERIUM WITH BIOCONTROL PROPERTIES BELONGING TO A LITTLE-STUDIED Pseudomonas sp.

GALVÁN TE; CONFORTE VP; SETUBAL J; PETROSELLI G; ERRA BALSELLS R; MIELNICHUK N; VOJNOV AA; YARYURA PM; BIANCO MI

Chapadmalal, Buenos Aires

Congreso; XVIII Congreso Sociedad Argentina de Microbiologia General; 2023

Sociedad Argentina de Microbiología General (SAMIGE)

Pseudomonas soli was identified as a new species of Pseudomonas in 2014. Up to date, 165www.samige.org.arinfo@samige.org.areight P. soli strains have been isolated worldwide and there is only phenotypic information regarding two strains: LMG 27941 and VMAP1. We previously isolated VMAP1 from the rhizospheric soil of healthy tomato (Solanum lycopersicum) plants. In a previous work, we studied the biocontrol activity of VMAP1 against Xanthomonas vesicatoria (a phytopatogenic bacteria) on tomato plants. The treatment with VMAP1 (applied by irrigation) and with its cell-free supernatant (applied by foliar spray) reduced the severity of the infection caused by X. vesicatoria by 44 % and 75 %, respectively. This triggered our interest in studying VMAP1 and the compounds it synthesizes, especially since the information available about P. soli is very scarce. Here, we present some results of the exhaustive genomic and phenotypic characterization of VMAP1 that we are carrying out. We first analyzed VMAP1 growth in different culture conditions and some phenotypic characteristics. We also investigated compounds produced by this bacterium. VMAP1 grew better at 20 and 28 °C than at 37 °C and tolerated 40 °C but not 45 °C. It also grew in a pH range of 5 to 10 and tolerated pH 4, 11 and 12. In addition, VMAP1 grew in medium containing up to 8 % NaCl and tolerated up to 16 % NaCl. VMAP1 presented twitching, swarming and swimming motilities. Most VMAP1 cells showed one unique polar flagellum, whereas a few ones showed two flagella. Biofilm assays in minimal and rich media are ongoing. Preliminary results suggested that VMAP1 presents a low surface adhesion capacity and consequent scanty biofilm formation in minimal medium. In addition, we sequenced and assembled the VMAP1 genome. Using different bioinformatics tools, we searched biosynthetic gene clusters (BGCs) involved in the synthesis of compounds with antimicrobial, antibiofilm and/or biocontrol/plant-growth promoting properties. We found BGCs encoding xantholysins (cyclic lipopeptides), HCN, rhamnolipids, pyoverdine (siderophore), tailocin (bacteriocin), lytic enzymes and indole acetic acid among others. Regarding the production of polysaccharides, we only found the alginate operon. Until now, we confirmed in vitro production of HCN, rhamnolipids and xantholysins A, B and C. We did not find genes encoding glycoside-modifying proteins; however, we found genes encoding a multidrug efflux system. This could explain why VMAP1 showed in vitrosensitivity to some antibiotics (kanamycin, gentamicin and polymyxin B) and resistance to others (ampicillin, chloramphenicol and streptomycin). Together, these results contribute to understanding the VMPA1 physiology and the mechanisms that confer this bacterium its biocontrol properties. Furthermore, understanding the metabolic characteristics of VMAP1 will provide information on its potential uses in the biotechnology industry.