Table 3. DMI resistance phenotype and cyp51 sequence information for Erysiphe necator isolates with various DMI sensitivities.
| Isolate | RF a | 136th Codon in Cyp51 | Other SNPs | Mean RQg | |||||
|---|---|---|---|---|---|---|---|---|---|
| Teb | Myc | Fen | Sequencingb | Repeat sequencingc | Genotypingd | nt 1119e | nt 1170f | ||
| BLP1 | 1 | 0.4 | 0.3 | TAT | nt | wild-type | A | G | 1.00e |
| BLP4 | 1 | 3 | 0.7 | TAT | TAT | wild-type | A | G | nt |
| MVP9 | 1 | 1 | 2 | TAT | nt | wild-type | A | A | 1.10e |
| PBP1 | 1 | 0.6 | 1 | TAT | nt | wild-type | A | A | 1.34e |
| SCCP4 | 2 | 0.05 | 2 | TAT | TAT | wild-type | A | A | nt |
| SNP1 | 1 | nt | nt | TAT | TAT | wild-type | nt | nt | nt |
| SNP3 | 0.6 | nt | nt | TAT | TAT | wild-type | nt | nt | nt |
| FH9-1 | 0.4 | nt | nt | TAT | TAT | nt | nt | nt | nt |
| VAHP6 | 24 | 33 | 20 | TAT | TAT | mix/wild-type | C | G | nt |
| BXP1A | 7 | 6 | 7 | TTT | TTT | pure mutant | A | A | 6.03d |
| GRP15 | 12 | 0.02 | 17 | TTT | nt | pure mutant | A | A | nt |
| GRP18 | 18 | 59 | 11 | TTT | TTT | pure mutant | A | A | nt |
| IVP3 | 2 | 0.2 | 2 | TTT | nt | pure mutant | A | A | 1.40e |
| IVP11 | 66 | nt | 15 | TTT | nt | pure mutant | A | A | nt |
| MDMRP5 | 22 | 35 | 7 | TTT | nt | pure mutant | A | A | 10.98c |
| MDMRP7 | 25 | 68 | 24 | TTT | TTT | pure mutant | A | A | 12.92b |
| PRP7 | 46 | 104 | 15 | TTT | nt | pure mutant | A | A | nt |
| ROP14 | 27 | 53 | 11 | TTT | TTT | pure mutant | A | A | nt |
| SUP13-2 | 11 | 34 | 5 | TTT | nt | pure mutant | A | A | nt |
| VAHP1 | 10 | 6 | 5 | TTT | nt | pure mutant | A | A | 1.85e |
| AMP1 | 65 | 23 | 59 | TAT | TWT | mix | C | R | 12.06c |
| IVP4 | 23 | 53 | 29 | TAT | TWT | mix | C | R | 10.73bc |
| JRP3 | 29 | 68 | 44 | TAT | TWT | mix | C | R | nt |
| VAHP4 | 25 | 27 | 32 | TWT | TWT | mix | C | R | 11.58bc |
| JRP1 | 32 | 87 | 8 | TWT | nt | mix | C | R | nt |
| JRP4 | 38 | 64 | 27 | TWT | TWT | mix | C | R | 18.85a |
| JWP1 | 137 | 45 | 79 | TWT | nt | mix | C | R | nt |
nt–not tested; cultures were either lost or isolates not selected for assays
a Resistance factor from EC50 mean of three assays per culture; Teb = tebuconazole; Myc = myclobutanil; Fen = fenarimol
b Corresponding to codon 136; TAT = tyrosine (Y), TTT = phenylalanine (F), TWT = double peak for middle nucleotide in sequence chromatograph
c Repeat sequencing with primer pair L419/R419
d Genotyping at the 136th codon: wild-type = TAT; pure mutant = TTT; mix = TTT/TAT or TWT
e Nucleotide 1119 displaying synonymous mutation at codon 326 (Ala-GCC/A; standard ambiguity code M for A/C)
f Nucleotide 1170 displaying a synonymous mutation at codon 343 (Gly = GGG/A; standard ambiguity code R for A/G)
g Cyp51 cDNA levels were quantified by the comparative CT method (∆∆CT) in the StepOne Plus instrument (Applied Biosystems). Relative expression (relative quantification, RQ) was calculated as 2-∆∆CT. Means with the same letter are not significantly different at ∝ = 0.05