Rice-Associated Rhizobacteria as a Source of Secondary Metabolites against Burkholderia glumae

• Published in: Molecules (Basel, Switzerland) Vol. 25; no. 11; p. 2567
• Main Authors: Peñaloza Atuesta, Giann Carlos, Murillo Arango, Walter, Eras, Jordi, Oliveros, Diego Fernándo, Méndez Arteaga, Jonh Jairo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31-05-2020; MDPI
• Subjects: Acetates - chemistry; Acetic acid; Acids; Agricultural production; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Antibacterial materials; Antimicrobial agents; Bacteria; Biomass; Burkholderia - pathogenicity; Burkholderia glumae; Crop diseases; Enterobacter; Enterobacter - classification; Enterobacter - metabolism; Ethyl acetate; Fermentation; Fractionation; Gas Chromatography-Mass Spectrometry; In vitro methods and tests; Liquid-liquid extraction; Magnetic Resonance Spectroscopy; Metabolites; metabolome; Metabolomics; Microorganisms; Minimum inhibitory concentration; Oryza - microbiology; Panicle blight; Pathogens; PGP; Phenylpropionates - chemistry; Phosphates - chemistry; Phosphorus; Phylogeny; Plant Diseases - microbiology; Plant Diseases - prevention & control; Plant growth; Plant growth promoters; rhizobacteria; Rhizosphere; Rhizosphere microorganisms; Rice; Rice fields; RNA, Ribosomal, 16S - genetics; rRNA 16S; Secondary Metabolism; Secondary metabolites; Seeds; Sheaths; Solubilization; Spectroscopy, Fourier Transform Infrared; Strains (organisms); Virulence - genetics; PGP; rhizobacteria; rice; Burkholderia glumae; metabolome
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25112567

Various diseases, including bacterial panicle blight (BPB) and sheath rot, threaten rice production. It has been established that
(
) is the causative agent of the above mentioned pathologies. In the present study, antagonistic activity, growth promotion, and the metabolite profiles of two rhizobacteria, isolated in different paddy fields, were assessed against
. Strains were identified based on 16S rRNA gene sequences, and the phylogenetic analyses showed that both strains belong to the genus
, with high similarity to the strain
NR146667.2 (99%). The antagonistic activity was assessed with the disc diffusion method. Active fractions were isolated through a liquid/liquid extraction with ethyl acetate (EtOAc) from the fermentation media, and their antibacterial activities were evaluated following the Clinical and Laboratory Standards Institute (CLSI) guidelines. The Pikovskaya modified medium was used to test the ability of in vitro inorganic phosphorus solubilization, and BSB1 proved to be the best inorganic phosphorus solubilizer, with a solubilization index (SI) of 4.5 ± 0.2. The glass-column fractionation of the EtOAc extracted from BCB11 produced an active fraction (25.9 mg) that inhibited the growth of five
strains by 85-95%. Further, metabolomic analysis, based on GC-MS, showed 3-phenylpropanoic acid (3-PPA) to be the main compound both in this fraction (46.7%), and in the BSB1 extract (28.6%). This compound showed antibacterial activity against all five strains of
with a minimum inhibitory concentration (MIC) of 1000 mg/L towards all of them. The results showed that rice rhizosphere microorganisms are a source of compounds that inhibit
growth and are promising plant growth promoters (PGP).