The opportunistic marine pathogen Vibrio parahaemolyticus becomes virulent by acquiring a plasmid that expresses a deadly toxin.
Acute hepatopancreatic necrosis disease (AHPND) is a severe, newly emergent penaeid shrimp disease caused by Vibrio parahaemolyticus that has already led to tremendous losses in the cultured shrimp industry. Until now, its disease-causing mechanism has remained unclear. Here we show that an AHPND-causing strain of V. parahaemolyticus contains a 70-kbp plasmid (pVA1) with a postsegregational killing system, and that the ability to cause disease is abolished by the natural absence or experimental deletion of the plasmid-encoded homologs of the Photorhabdus insect-related (Pir) toxins PirA and PirB. We determined the crystal structure of the V. parahaemolyticus PirA and PirB (PirA(vp) and PirB(vp)) proteins and found that the overall structural topology of PirA(vp)/PirB(vp) is very similar to that of the Bacillus Cry insecticidal toxin-like proteins, despite the low sequence identity (<10%). This structural similarity suggests that the putative PirAB(vp) heterodimer might emulate the functional domains of the Cry protein, and in particular its pore-forming activity. The gene organization of pVA1 further suggested that pirAB(vp) may be lost or acquired by horizontal gene transfer via transposition or homologous recombination.
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan; Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan;
Chung-Te
CT
Lee
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan; Department of Life Science, National Taiwan University, Taipei 104, Taiwan;
I-Tung
IT
Chen
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan; Department of Life Science, National Taiwan University, Taipei 104, Taiwan;
Yi-Ting
YT
Yang
Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan;
Tzu-Ping
TP
Ko
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan;
Yun-Tzu
YT
Huang
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan;
Jiun-Yan
JY
Huang
Graduate Institute of Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan;
Ming-Fen
MF
Huang
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan;
Shin-Jen
SJ
Lin
Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 115, Taiwan; Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 104, Taiwan;
Chien-Yu
CY
Chen
Shih-Shun
SS
Lin
Institute of Biotechnology, National Taiwan University, Taipei 104, Taiwan;
Shih-Shuen
SS
Lin
Aquaculture Pathology Laboratory, School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721;
Donald V
DV
Lightner
Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan;
Han-Ching
HC
Wang
Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan;
Andrew H-J
AH
Wang
Graduate Institute of Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan; gracelow@mail.ncku.edu.tw h061453@mail.ncku.edu.tw wanghc@tmu.edu.tw.
Hao-Ching
HC
Wang
Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; gracelow@mail.ncku.edu.tw h061453@mail.ncku.edu.tw wanghc@tmu.edu.tw.
Lien-I
LI
Hor
Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan; Department of Life Science, National Taiwan University, Taipei 104, Taiwan; Center of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan gracelow@mail.ncku.edu.tw h061453@mail.ncku.edu.tw wanghc@tmu.edu.tw.
Chu-Fang
CF
Lo
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification*; D001427:Bacterial Toxins / Q000235:genetics / Q000302:isolation & purification*; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D033561:Penaeidae / Q000382:microbiology; D010957:Plasmids / Q000235:genetics / Q000378:metabolism*; D018272:Porins / Q000737:chemistry; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D018272:Porins
AHPND; Pir toxin; Vibrio parahaemolyticus; shrimp; virulence plasmid