Isolation and Characterization of Burkholderia rinojensis sp. nov., a Non-Burkholderia cepacia Complex Soil Bacterium with Insecticidal and Miticidal Activities

Abstract

Isolate A396, a bacterium isolated from a Japanese soil sample demonstrated strong insecticidal and miticidal activities in laboratory bioassays. The isolate was characterized through biochemical methods, fatty acid methyl ester (FAME) analysis, sequencing of 16S rRNA, multilocus sequence typing and analysis, and DNA-DNA hybridization. FAME analysis matched A396 to Burkholderia cenocepacia, but this result was not confirmed by 16S rRNA or DNA-DNA hybridization. 16S rRNA sequencing indicated closest matches with B. glumae and B. plantarii. DNA-DNA hybridization experiments with B. plantarii, B. glumae, B. multivorans, and B. cenocepacia confirmed the low genetic similarity (11.5 to 37.4%) with known members of the genus. PCR-based screening showed that A396 lacks markers associated with members of the B. cepacia complex. Bioassay results indicated two mechanisms of action: through ingestion and contact. The isolate effectively controlled beet armyworms (Spodoptera exigua; BAW) and two-spotted spider mites (Tetranychus urticae; TSSM). In diet overlay bioassays with BAW, 1% to 4% (vol/vol) dilution of the whole-cell broth caused 97% to 100% mortality 4 days postexposure, and leaf disc treatment bioassays attained 75% ؎ 22% mortality 3 days postexposure. Contact bioassays led to 50% larval mortality, as well as discoloration, stunting, and failure to molt. TSSM mortality reached 93% in treated leaf discs. Activity was maintained in cell-free supernatants and after heat treatment (60°C for 2 h), indicating that a secondary metabolite or excreted thermostable enzyme might be responsible for the activity. Based on these results, we describe the novel species Burkholderia rinojensis, a good candidate for the development of a biocontrol product against insect and mite pests.

Cytotoxic Spliceostatins from Burkholderia sp. and Their Semisynthetic Analogues

“…Chemical shifts are reported in ppm and were referenced to the deuterated solvent using the digital lock. High-resolution ESIMS analyses were performed on a Waters Acquity UPLC/Synapt G2 QTOF mass spectrometer, using an ACQUITY UPLC BEH C 18 , 100−1200 m/z scan). Preliminary reversephase purification was performed using a Sephadex LH20 column with methanol as an eluent.…”

Microbial Biopesticides in Agroecosystems

“…Betaproteobacteria represents another class including species with a significant potential as biocontrol agents. An insecticidal strain of Burkholderia rinojensis has recently been discovered and developed into a product acting by ingestion and contact against diverse chewing and sucking insects and mites [22]. The insecticidal action relies on different metabolites and the commercial product is based on heat-killed cells and spent fermentation media.…”

Insect Pathogenic Bacteria in Integrated Pest Management

“…More recently, the insecticidal properties of a new strain isolated in soil from Japan and identified as B. rinojensis sp. nov., were discovered [ 51 ]. Whole cell broth cultures of this bacterial strain, named A396, show oral toxicity and contact effects against the beet armyworm Spodoptera exigua Hübner (Lepidoptera: Noctuidae) and the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae).…”