Characterization of filamentous bacteriophage PE226 infecting Ralstonia solanacearum strains.
OBJECTIVE
The aim of this study was to isolate and characterize new bacteriophages that infect a wide range of plant pathogenic Ralstonia solanacearum strains.


RESULTS
Fifteen bacteriophages were isolated from pepper, tomato and tobacco plant rhizospheres infected with R. solanacearum. A host specificity analysis of the isolated phages using nine strains of R. solanacearum indicated great phage diversity in a single soil. Two phages, PE226 and TM227, showed clear plaques on all nine bacterial hosts tested and were virtually identical in morphology and genome. PE226, an Inovirus, is a long, flexible, filamentous phage carrying a circular (+) sense single-strand DNA genome of 5475 nucleotides. DNA sequences of PE226 exhibited nine open reading frames (ORF) that were not highly similar to those of other phages infecting R. solanacearum. The genome organization of PE226 was partially similar to that of p12J of Ralstonia pickettii. One ORF of PE226 showed identity to the zot gene encoding zonula occludens toxin of Vibrio cholera. Orf7 of PE226 was also present in the genome of R. solanacearum strain SL341. However, SL341, a highly virulent strain in tomato, was still sensitive to phage PE226.


CONCLUSIONS
A new, flexible, filamentous phage PE226 infected wide range of R. solanacearum strains and carried unique circular single-strand DNA genome with an ORF encoding Zot-like protein.


CONCLUSIONS
PE226 may be a new type of temperate phage, based on its lytic nature on a wide range of hosts and the presence of a zot homologue in a host bacterial genome.
Department of Applied Biology, College of Natural Resources and Life Science, Dong-A University, Busan, Korea.
S
S
Murugaiyan
J Y
JY
Bae
J
J
Wu
S D
SD
Lee
H Y
HY
Um
H K
HK
Choi
E
E
Chung
J-H
JH
Lee
S-W
SW
Lee
D000595:Amino Acid Sequence; D004277:DNA, Single-Stranded / Q000737:chemistry; D004279:DNA, Viral / Q000737:chemistry; D016679:Genome, Viral; D058507:Host Specificity; D017912:Inovirus / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure; D018551:Solanum lycopersicum / Q000382:microbiology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D043368:Ralstonia solanacearum / Q000821:virology*; D058441:Rhizosphere; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D014764:Viral Proteins