Biochemical, genetic and pathogenic characterization of Burkholderia andropogonis and taxonomic reassessment of the species

Author(s)

Lucilene Lopes Santos

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2015-11-12

Examining board members

Suzete Aparecida Lanza Destéfano; Fabiana Fantinatti Garboggini; Valeria Maia de Oliveira; Ricardo Harakava; Ivan Paulo Bedendo

• Advisor: Suzete Aparecida Lanza Destéfano

Abstract

Burkholderia andropogonis initially described by Smith (1911) as the causal agent of leaf stripe disease on sorghum (Sorghum bicolor), affects a wide range of host plants economically important with an extensive geographical distribution. This bacterial species has unique features absent in most plant pathogens such as a single polar sheathed flagellum and rhizobitoxine production. The aim of this study was to assess the genetic, biochemical and pathogenic diversity among Burkholderia andropogonis strains and to establish the phylogenetic relationship of this bacterial species within Burkholderia genus. Differential biochemical and physiological features were not observed among strains isolated from different host and different geographical origins, as well as host specialization was not observed in the pathogenicity tests on distinct plant species. In the molecular characterization the rep-PCR technique was a sensitive method to measure the genetic variation within this bacterial species once the combined analysis using REP, ERIC and BOX-PCR allowed separation of strains into clusters according to specific hosts and/or geographical location. . The phylogenetic analysis using 16S rRNA gene and multilocus sequence analysis (MLSA) using five housekeeping genes (gyrB, recA, lepA, atpD e gltB) allowed clear separation of B. andropogonis from the other species of the genus, with low percentages of similarity among the genes sequences. After the genome sequencing of B. andropogonis type strain a multilocus analysis using 30 different conserved genes was also performed and again, B. andropogonis remained separated from the species of the Burkholderia genus. In addition, the average nucleotide identity (ANI), tetranucleotide frequency signature (TETRA), and percentage of conserved proteins (POCP) analyses were also carried out, and B. andropogonis species showed lower values when compared to the other Burkholderia species, reinforcing the distance observed in the molecular analyses. Our findings clearly indicates that B. andropogonis belongs to a distinct group and may represent a new genus (AU)

• FAPESP's process: 11/12222-2 - Phenotipic, genetic and pathogenic characterization of Burkholderia andropogonis strains from different host plants
• Grantee: Lucilene Lopes dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate