MOLECULAR IDENTIFICATION AND PHYLOGENY OF TWO ENDOPHYTIC PLANT GROWTH-PROMOTING SPORE-FORMING BACTERIA ISOLATED FROM YERBA MATE (ILEX PARAGUARIENSIS ST. HIL.)

CORTESE, J.; SVIERCZ OLIVETTI, O.; CASTRILLO, M.; ZAPATA, P.; LACZESKI, M.

Simposio; I SIMICRON: Simposio de Microbiología de Rondonia, Salud, Ambiente e Innovación; 2021

One of the most economically important crops in Argentina is Ilex paraguariensis St. Hil., a plant that is also commonly called yerba mate. It is widely marketed in South America; but also, it is consumed worldwide. It is emphasized that despite this overall consumption, yerba mate can only grow in certain regions of Argentina, Paraguay, and Brazil due to unique soil characteristics, such as lateritic soils, and warm and moist weather. Currently, there are plantations of very good performance in the region, however, there are concerns about the increase of yerba mate degraded crops, as a result of the monoculture system, erosion and compaction of soil, and nutrient loss combined with little or no soil fertilization. This motivates the research and development of a biofertilizer from native bacteria to recover crop performance. For this reason, two endophytic bacteria were isolated from roots of I. paraguariensis St Hil. and selected for their plant growth-promoting properties (PGP) showed in vitro. The strains were morphologically identified as Bacillus. Bacteria closely related cannot be distinguished from other species simply by 16S rRNA gene sequence. In this context, the objective of the present work was to molecularly identify two endophytic plant growth-promoting spore-forming bacteria isolated from yerba mate by the analysis of the 16S rRNA, 23S rRNA and gyrB concatenated gene sequences. First, to advance knowledge both bacterial genomes were sequenced. The annotated sequence of B. altitudinis (GenBank accession number: CP022319) was used as a reference for the detection of the genes in both genomes. Gene search and analysis was performed with Geneious 11.0.1 software. The sequences obtained were compared with the nucleotide and protein databases of the National Center for Biotechnology Information (NCBI), using the BLASTn and BLASTx platforms, respectively. Sequences of the 16S rRNA, 23S rRNA and gyrB genes from different species belonging to the genus Bacillus were selected and manually concatenated using the Mega 6.06 software. The sequences were analyzed by the Neighbor Joining, Maximum Likelihood and Maximum Parsimony methods using the Bootstrap test with 1000 replicates. The analysis of identity and similarity and the construction of monophyletic clades supported by a bootstrap of 100%, allowed us to identify both bacterial strains as B. altitudinis. It is concluded that the 16S rRNA, 23S rRNA, and gyrB genes are an efficient tool for the identification and taxonomic analysis of members of the Bacillus genus.