Putative new mechanisms involved in wheat growth promotion and biocontrol were discovered by inspecting pgpb genomes

MANNO, MARIANO TORRES; GIZZI, F; BLANCATO, VÍCTOR S.; DAURELIO, LUCAS; ESPARIZ, M

Congreso; LVII Reunión Anual de SAIB; 2021

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Wheat is one of the principal cereals of Argentine agriculture and its cultivation is considered strategic in rotations due to itscontribution to the sustainability of the soils. Plant growth promoting bacteria (PGPB) can colonize the rhizospheres of plants,and act as biofertilizers and antagonists of pathogens (biopesticides). Due to this, they emerged as a technological alternativefor a sustainable agricultural exploitation, as a replacement for agrochemicals. Many of these microorganisms belong to thegenus Bacillus and proliferate in soils exploited agriculturally. In this work we characterize six wheat associated strainspresenting PGPB and biocontrol propertyies belonging to Bacillus velezensis and Priestia megaterium (formerly known as Bacillus megaterium). The whole genome sequences were determined using Illumina and PacBio technology and the taxonomyidentity was defined using Multiple Locus Sequences Analysis (MLSA) and Average Nucleotide Identity (ANI). Acomparative genomic analysis was processed in order to identify the plant growth promoting mechanism of these strains.Known secondary metabolite and general PGP pathways were searched first using the GeM-Pro algorithm. This pathwaysearch upon the six strains and available genomes from B. velezensis and P. megaterium groups expose some of the possiblemechanisms in growth promoting and biocontrol. Additional potential pathways were searched using the antiSMASH platformresulting in potential new pathways for P. megaterium and B. velezensis isolated strains. Another comparative genomicanalysis with these new pathways was performed with the available genomes with the aim of finding the exclusive genes thatcorrespond with the differential plant growth promoting phenotypes. As result, we found exclusive pathways in the P.megaterium strains involving Non-Ribosomal Peptide Synthases (NRPS) and Polyketide Synthase (PKS) that were notdetected in the non redundant nucleotide GenBank database. Secondly, thanks to the PacBio technology, we confirm that thesegene clusters are coded in two different plasmids. This may suggest that these are recently acquired gene clusters as a resultof adaptation to the environment