TABLE 2.
Effects of i4 insertions on substrate transfer and pilus production
| Straina | Virulenceb | Transfer of:
|
Exocellular VirB2f | ||
|---|---|---|---|---|---|
| T-DNAc | VirE2d | pML122ΔKme | |||
| A348 | +++ (++) | NA | NA | 1.5 × 10−4 | +++ (+) |
| PC1006 (ΔB6) | − | − | − | <1 × 10−8 | − |
| Plac-virB6 | +++ (++) | NA | NA | 6.8 × 10−5 | +++ (+) |
| PvirB-virB6 | +++ (−) | NA | NA | 1.7 × 10−4 | +++ (+) |
| E29 | − | − | − | <1 × 10−8 | − |
| D60 | − | − | − | <1 × 10−8 | − |
| Q85 | − | − | − | <1 × 10−8 | − |
| T114 | − | − | − | <1 × 10−8 | − |
| Q140 | − | − | ++ | 1.2 × 10−5 | − |
| L165 | − | − | − | <1 × 10−8 | − |
| L191 | − | − | ++ | 9.8 × 10−6 | − |
| F225 | − | − | − | <1 × 10−8 | − |
| I250 | − | − | − | <1 × 10−8 | − |
| A280 | +++ (−) | NA | NA | 5.8 × 10−5 | +++ (+) |
PC1006 strains expressed native virB6 from the Plac or PvirB promoter or virB6.i4 alleles from PvirB.
Monitored by tumor formation at inoculated wound sites of Kalanchoe leaves. Pluses denote virulence of strains maintained on plants at 20°C, and pluses in parentheses denote virulence of strains maintained on plants at 28°C. See the text for experimental details.
Mixed infections with the T-DNA deletion strain LBA4404 (35). NA, not applicable (strains exhibiting wild-type virulence cannot be tested for export of individual substrates by mixed infection assays).
Mixed infections with the virE2 mutant mx358.
Conjugation assays with i4 mutant strains as donors and A348 Spcr as recipient. Values are transconjugants per donor cell.
T-pilus production as monitored by abundance of exocellular VirB2 pilin. Pluses denote relative abundance of exocellular pilin isolated from strains induced for vir gene expression at 20°C, and pluses in parentheses denote the relative abundance of exocellular pilin from strains induced at 28°C.