Whole Genome Sequencing and Root Colonization Studies Reveal Novel Insights in the Biocontrol Potential and Growth Promotion by Bacillus subtilis MBI 600 on Cucumber

Anastasios Samaras; Marios Nikolaidis; Maria Luisa Antequera-Gómez; Jesus Cámara-Almirón; Diego Romero; Thomas Moschakis; Grigoris D Amoutzias; Georgios S Karaoglanidis

doi:10.3389/fmicb.2020.600393

Whole Genome Sequencing and Root Colonization Studies Reveal Novel Insights in the Biocontrol Potential and Growth Promotion by Bacillus subtilis MBI 600 on Cucumber

Front Microbiol. 2021 Jan 12:11:600393. doi: 10.3389/fmicb.2020.600393. eCollection 2020.

Authors

Anastasios Samaras¹, Marios Nikolaidis², Maria Luisa Antequera-Gómez³, Jesus Cámara-Almirón³, Diego Romero³, Thomas Moschakis⁴, Grigoris D Amoutzias², Georgios S Karaoglanidis¹

Affiliations

¹ Laboratory of Plant Pathology, Faculty of Agriculture, Forestry and Natural Environment, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece.
² Bioinformatics Laboratory, Department of Biochemistry and Biotechnology, University of Thessaly, Larisa, Greece.
³ Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Departamento de Microbiología, Universidad de Málaga, Málaga, Spain.
⁴ Laboratory of Dairy Science and Technology, Department of Food Science and Technology, Faculty of Agriculture, Forestry and Natural Environment, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece.

Abstract

Bacillus spp. MBI 600 is a gram-positive bacterium and is characterized as a PGPR strain involved in plant growth promotion and control of various plant pathogens which has recently been introduced into the agricultural practice. In this study we performed a Next Generation Sequencing analysis, to analyze the full genome of this microorganism and to characterize it taxonomically. Results showed that MBI 600 strain was phylogenetically close to other Bacillus spp. strains used as biocontrol agents and identified as B. subtilis. GOG analysis showed clusters contributed to secondary metabolites production such as fengycin and surfactin. In addition, various genes which annotated according to other plant-associated strains, showed that play a main role in nutrient availability from soil. The root colonization ability of MBI 600 strain was analyzed in vivo with a yellow fluorescence protein (yfp) tag. Confocal laser scanning microscopy of cucumber roots treated with yfp-tagged MBI 600 cells, revealed that the strain exhibits a strong colonization ability of cucumber roots, although it is affected significantly by the growth substrate of the roots. In vitro and in planta experiments with MBI 600 strain and F. oxysporum f.sp. radicis cucumerinum and P. aphanidernatum, showed a high control ability against these soilborne pathogens. Overall, our study demonstrates the effectiveness of MBI 600 in plant growth promotion and antagonism against different pathogens, highlighting the use of this microorganism as a biocontrol agent.

Keywords: Bacillus spp.; Fusarium oxysporum f.sp. radicis cucumerinum; plant growth Promoting bacteria; root colonization; whole genome analysis; yellow fluorescence protein-tagging.