Abstract

NUNEZ, Renzo A. Valdez et al. Genetic characterization of rice endophytic bacteria (Oryza sativa L.) with antimicrobial activity against Burkholderia glumae. Rev. argent. microbiol. [online]. 2020, vol.52, n.4, pp.51-60. ISSN 0325-7541.

The aim of the present study was to isolate, select and characterize endophytic bacteria in rice inhibiting Burkholderia glumae THT as well as to characterize the genetic diversity and virulence factors in strains of B. glumae and Burkholderia gladioli of rice. Rice plants were collected in 4 departments from the northern region of Peru, isolating endophytic bacteria, aftertissue sterilization, at 30°C (48 h) in Trypticase SoyAgar (TSA), evaluating the antimicrobial activity against B. glumae THT, production of siderophores, resistance of toxoflavine and partial sequencing of the 16S rRNA gene. Furthermore, B. glumae and B. gladioli were isola-ted in selective medium (pH 4.5) at 41 °C/72h. Molecular identification was performed using BOX-PCR and sequencing of the 16S rRNA gene, in addition to the production of extracellular enzymes, motility tests and sensitivity/resistance to bactericides. One hundred and eighty nine (189) endophytic bacteria were isolated, and only 9 strains showed antimicrobial activity against B. glumae THT, highlighting Burkholderia vietnamiensis TUR04-01, B. vietnamiensis TUR04-03 and Bacillus aryabhattai AMH12-02. The strains produced siderophores and at least 55.5% were resistant to toxoflavin. Additionally, 17 strains were grouped into 9 BOX-PCR profiles, where 16 had similarity with B. glumae LMG2196T (100%) and 1 with B. gladioli NBRC 13700T (99.86%). High diversity was found according to geographical origin and virulence factors. In conclusion, strains of the genus Bacillus and Burkholderia are potential biocontrol agents against B. glumae.

Keywords : Biological control; Virulence factors; Bacterial panicle blight of rice.

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