Identification of an insecticidal toxin produced by Enterobacter sp. strain 532 isolated from diseased Bombyx mori silkworms

Mai Morishita, Akitsu Masuda, Hiroaki Mon, Man Lee, Takahiro Kusakabe, Kosuke Tashiro, Chisa Yasunaga-Aoki, Kazuhiro Iiyama

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Although Enterobacter sp. 532 shows pathogenicity in Bombyx mori, the insecticidal mechanisms are unclear. Here, we identified and characterised an insecticidal protein from Enterobacter. The insecticidal protein was purified from the strain and inoculated into B. mori larvae. Intracellular proteins were prepared, purified and separated by preparative native polyacrylamide gel electrophoresis (PAGE); one protein band had insecticidal activity. Sodium dodecyl sulfate-PAGE showed the presence of several bands, indicating that the insecticidal protein formed a complex. Peptide mass fingerprinting of a prominent 255.3-kDa band revealed 64 peptides that matched one protein with 33.0% sequence coverage. This protein was a homologue of the A component of the toxin complex (Tc), and the VRP1 domain was conserved; thus, the gene was named itcA (insecticidal toxin complex A). In the itcA downstream region, B and C component gene homologues were found, and these genes were located on an 86.2-kb contig sequence. Two repA genes and 27 genes related to conjugation transfer of plasmids were located on the contig, suggesting that the contig originated from a mobilisable plasmid. Therefore, these findings suggested that the strain may have acquired the Tc genes by horizontal transfer. This is the first description of Tc produced by the genus Enterobacter.

Original languageEnglish
Article numberfny295
JournalFEMS microbiology letters
Volume366
Issue number2
DOIs
Publication statusPublished - Jan 9 2019

Fingerprint

Enterobacter
Bombyx
Proteins
Genes
Plasmids
Gene Components
Native Polyacrylamide Gel Electrophoresis
Horizontal Gene Transfer
Peptide Mapping
Sodium Dodecyl Sulfate
Larva
Virulence
Polyacrylamide Gel Electrophoresis
Peptides

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology
  • Genetics

Cite this

@article{dc2953a6da3242c48a8cf36795bb7469,
title = "Identification of an insecticidal toxin produced by Enterobacter sp. strain 532 isolated from diseased Bombyx mori silkworms",
abstract = "Although Enterobacter sp. 532 shows pathogenicity in Bombyx mori, the insecticidal mechanisms are unclear. Here, we identified and characterised an insecticidal protein from Enterobacter. The insecticidal protein was purified from the strain and inoculated into B. mori larvae. Intracellular proteins were prepared, purified and separated by preparative native polyacrylamide gel electrophoresis (PAGE); one protein band had insecticidal activity. Sodium dodecyl sulfate-PAGE showed the presence of several bands, indicating that the insecticidal protein formed a complex. Peptide mass fingerprinting of a prominent 255.3-kDa band revealed 64 peptides that matched one protein with 33.0{\%} sequence coverage. This protein was a homologue of the A component of the toxin complex (Tc), and the VRP1 domain was conserved; thus, the gene was named itcA (insecticidal toxin complex A). In the itcA downstream region, B and C component gene homologues were found, and these genes were located on an 86.2-kb contig sequence. Two repA genes and 27 genes related to conjugation transfer of plasmids were located on the contig, suggesting that the contig originated from a mobilisable plasmid. Therefore, these findings suggested that the strain may have acquired the Tc genes by horizontal transfer. This is the first description of Tc produced by the genus Enterobacter.",
author = "Mai Morishita and Akitsu Masuda and Hiroaki Mon and Man Lee and Takahiro Kusakabe and Kosuke Tashiro and Chisa Yasunaga-Aoki and Kazuhiro Iiyama",
year = "2019",
month = "1",
day = "9",
doi = "10.1093/femsle/fny295",
language = "English",
volume = "366",
journal = "FEMS Microbiology Letters",
issn = "0378-1097",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Identification of an insecticidal toxin produced by Enterobacter sp. strain 532 isolated from diseased Bombyx mori silkworms

AU - Morishita, Mai

AU - Masuda, Akitsu

AU - Mon, Hiroaki

AU - Lee, Man

AU - Kusakabe, Takahiro

AU - Tashiro, Kosuke

AU - Yasunaga-Aoki, Chisa

AU - Iiyama, Kazuhiro

PY - 2019/1/9

Y1 - 2019/1/9

N2 - Although Enterobacter sp. 532 shows pathogenicity in Bombyx mori, the insecticidal mechanisms are unclear. Here, we identified and characterised an insecticidal protein from Enterobacter. The insecticidal protein was purified from the strain and inoculated into B. mori larvae. Intracellular proteins were prepared, purified and separated by preparative native polyacrylamide gel electrophoresis (PAGE); one protein band had insecticidal activity. Sodium dodecyl sulfate-PAGE showed the presence of several bands, indicating that the insecticidal protein formed a complex. Peptide mass fingerprinting of a prominent 255.3-kDa band revealed 64 peptides that matched one protein with 33.0% sequence coverage. This protein was a homologue of the A component of the toxin complex (Tc), and the VRP1 domain was conserved; thus, the gene was named itcA (insecticidal toxin complex A). In the itcA downstream region, B and C component gene homologues were found, and these genes were located on an 86.2-kb contig sequence. Two repA genes and 27 genes related to conjugation transfer of plasmids were located on the contig, suggesting that the contig originated from a mobilisable plasmid. Therefore, these findings suggested that the strain may have acquired the Tc genes by horizontal transfer. This is the first description of Tc produced by the genus Enterobacter.

AB - Although Enterobacter sp. 532 shows pathogenicity in Bombyx mori, the insecticidal mechanisms are unclear. Here, we identified and characterised an insecticidal protein from Enterobacter. The insecticidal protein was purified from the strain and inoculated into B. mori larvae. Intracellular proteins were prepared, purified and separated by preparative native polyacrylamide gel electrophoresis (PAGE); one protein band had insecticidal activity. Sodium dodecyl sulfate-PAGE showed the presence of several bands, indicating that the insecticidal protein formed a complex. Peptide mass fingerprinting of a prominent 255.3-kDa band revealed 64 peptides that matched one protein with 33.0% sequence coverage. This protein was a homologue of the A component of the toxin complex (Tc), and the VRP1 domain was conserved; thus, the gene was named itcA (insecticidal toxin complex A). In the itcA downstream region, B and C component gene homologues were found, and these genes were located on an 86.2-kb contig sequence. Two repA genes and 27 genes related to conjugation transfer of plasmids were located on the contig, suggesting that the contig originated from a mobilisable plasmid. Therefore, these findings suggested that the strain may have acquired the Tc genes by horizontal transfer. This is the first description of Tc produced by the genus Enterobacter.

UR - http://www.scopus.com/inward/record.url?scp=85061147794&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85061147794&partnerID=8YFLogxK

U2 - 10.1093/femsle/fny295

DO - 10.1093/femsle/fny295

M3 - Article

C2 - 30596999

AN - SCOPUS:85061147794

VL - 366

JO - FEMS Microbiology Letters

JF - FEMS Microbiology Letters

SN - 0378-1097

IS - 2

M1 - fny295

ER -