Isolation of a Pseudomonas solanacearum-specific DNA probe by subtraction hybridization and construction of species-specific oligonucleotide primers for sensitive detection by the polymerase chain reaction.
A subtraction hybridization technique was employed to make a library enriched for Pseudomonas solanacearum-specific sequences. One cloned fragment, PS2096, hybridized under stringent conditions to DNA of 82 P. solanacearum strains representing all subgroups of the species. Other plant-associated bacteria, including closely related species such as Pseudomonas capacia, Pseudomonas picketti, or Pseudomonas syzygii, did not hybridize to PS2096. A minimum number of between 4 x 10(5) and 4 x 10(6) P. solanacearum cells could routinely be detected with PS2096 labelled either with [32P]dCTP or with digoxigenin-11-dUTP. To improve the sensitivity of detection, PS2096 was sequenced to allow the construction of specific oligonucleotide primers to be used for polymerase chain reaction (PCR) amplification. After 50 cycles of amplification, 5 to 116 cells, depending on the strain, could reproducibly be detected by visualization of a 148-bp PCR product on an agarose gel. A preliminary field trial in Burundi with the probe and PCR primers has confirmed that they are sensitive tools for specifically detecting low-level infections of P. solanacearum in potato tubers.
Seal
S E
SE
Sainsbury Laboratory, John Innes Centre, Norwich, Norfolk, United Kingdom.
Jackson
L A
LA
Daniels
M J
MJ
D001483:Base Sequence; D003001:Cloning, Molecular; D015342:DNA Probes; D015723:Gene Library; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides; D010944:Plants / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011549:Pseudomonas / Q000235:genetics / Q000302:isolation & purification*; D013045:Species Specificity
D015342:DNA Probes; D009841:Oligonucleotides