Table 4.
GPGV isolates and detection methods
| Vineyard | Group | Sample | Plant | Infection level | Clade | Ct values | PCR Det primer | ELISA | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2018 | 2019 | 2020 | 2021 | ||||||||
| HEC | Latent | HEC-L 1 | 7/8 | l | l | l | l | A | 25.02 ± 1.71 | + | +++ |
| HEC-L 2 | 7/27 | l | l | l | l | A | 23.61 ± 1.67 | + | ++ | ||
| HEC-L 3 | 8/23 | l | l | l | l | A | 25.86 ± 1.1 | + | + | ||
| HEC-L 7 | 9/24 | l | l | l | l | A | 24.52 ± 0.74 | + | +++ | ||
| Symptomatic | HEC-S 1 | 7/10 | svs | ms | sls | ms | C | 24.55 ± 2.55 | + | +++ | |
| HEC-S 2 | 7/18 | svs | svs | sls | ms | C | 24.24 ± 2.02 | + | +++ | ||
| HEC-S 3 | 8/18 | sls | ms | ms | svs | A | 25.94 ± 1.91 | + | + | ||
| HEC-S 4 | 5/12 | svs | l | sls | svs | C | 24.44 ± 2.06 | + | +++ | ||
| Immediately symptomatic | HEC-IS 1 | 4/12 | h | h | ms | svs | A | 23.62 ± 0.89 | + | ++ | |
| HEC-IS 2 | 7/22 | h | h | ms | svs | C | 25.66 ± 1.64 | + | ++ | ||
| HEC-IS 3 | 8/7 | h | h | ms | ms | A | 22.67 ± 0.94 | + | ++++ | ||
| HEC-IS 4 | 9/31 | h | h | h | ms | A | 23.65 ± 1.09 | + | ++++ | ||
| NIM | Latent | NIM-L 1 | 1/5 | l | l | l | C | 22.92 ± 0.38 | + | ++++ | |
| NIM-L 2 | 3/40 | l | l | l | C | 24.41 ± 0.56 | + | ++ | |||
| NIM-L 3 | 4/13 | l | l | l | A | 22.68 ± 0.57 | + | +++ | |||
| NIM-L 4 | 8/20 | l | l | l | B | 25.95 ± 0.70 | + | +++ | |||
| Symptomatic | NIM-S 1 | 3/17 | svs | ms | ms | C | 23.12 ± 0.75 | + | ++++ | ||
| NIM-S 2 | 6/10 | svs | svs | ms | C | 22.99 ± 0.32 | + | ++++ | |||
| NIM-S 3 | 7/10 | svs | svs | svs | C | 23.42 ± 0.41 | + | +++ | |||
| NIM-S 4 | 10/23 | svs | ms | svs | C | 22.49 ± 1.12 | + | ++++ | |||
| Immediately symptomatic | NIM-IS 1 | 2/28 | h | h | sls | C | 22.31 ± 0.70 | + | +++ | ||
| NIM-IS 2 | 3/21 | h | h | sls | C | 22.53 ± 0.38 | + | ++++ | |||
| NIM-IS 3 | 10/20 | h | h | sls | C | 23.35 ± 0.47 | + | +++ | |||
| NIM-IS 4 | 10/36 | h | h | ms | C | 24.35 ± 0.37 | + | ++++ | |||
| Positiv control | 34.18 ± 0.55 | + | |||||||||
| Negative control | N/A | − | |||||||||
| NTC | N/A | − | |||||||||
Listed are samples from three different GPGV infection groups (latent (L), symptomatic (S), immediately symptomatic (IS)) from HEC and NIM vineyards, classified according their infection levels between 2018 and 2021 (Table 2), with corresponding results of isolate determination, quantitative real time PCR (qRT-PCR), PCR and ELISA. Isolates were determined by Sanger sequencing. Upper case letters correspond to the assignment of isolates into GPGV clades A–C [19]. Cycle threshold (Ct) values of qRT-PCR indicate higher virus titer e.g. virus load
ELISA results were ranked into five categories according to their absorbance values—: x < 100;+: 100 < x < 300;++: 300 < x < 800;+++: 800 < x < 1700; ++++: 1700 < x
NTC Non template control
N/A not applicable