Table 2. The sensitivity of the multiplexed Luminex MagPlex-TAG pospiviroid array when tested using a ten-fold serial dilutions of a total RNA extract from a Solanum lycopersicum sample infected with Potato spindle tuber viroid (PSTVd, isolate #N).
| PSTVd RNAconcentration (g/µL)a | Assays of the Luminex MagPlex-TAG Pospiviroid array (mean MFI ± standard deviation)b,c,d | ||||||||||
| CSVd | CEVd | CLVd | IrVd-1 | PCFVd | PSTVd | TASVd | TCDVd | TPMVd | PospUni | PlantIC | |
| 2.68E-07 | 411±17 | 300±6 | 373±22 | 446±6 | 408±88 | 7651±517 | 602±80 | 328±15 | 494±11 | 45330±260 | 57393±1277 |
| 2.68E-08 | 295±99 | 273±64 | 290±7 | 466±10 | 411±7 | 6244±227 | 517±28 | 241±41 | 443±0 | 49506±1936 | 53159±1619 |
| 2.68E-09 | 255±22 | 278±57 | 276±1 | 311±16 | 380±14 | 1179±93 | 330±128 | 193±1 | 256±0 | 30707±179 | 43386±244 |
| 2.68E-10 | 191±14 | 201±26 | 231±24 | 277±42 | 317±34 | 457±48 | 246±50 | 182±11 | 254±15 | 19679±415 | 22976±1187 |
| 2.68E-11 | 180±6 | 170±48 | 205±2 | 300±33 | 388±33 | 236±51 | 285±66 | 142±1 | 188±30 | 1899±186 | 19846±1155 |
| 2.68E-12 | 145±13 | 190±17 | 175±13 | 248±6 | 390±52 | 146±60 | 213±33 | 177±17 | 179±26 | 367±14 | 13226±126 |
| 2.68E-13 | 182±74 | 202±32 | 255±5 | 293±30 | 367±14 | 197±11 | 184±62 | 159±11 | 210±14 | 247±25 | 13995±1152 |
a Each sample was tested in triplicate.
b Acronyms refer to assays of the multiplexed array specific for: CSVd - Chrysanthemum stunt viroid; CEVd - Citrus exocortis viroid; CLVd - Columnea latent viroid; IrVd-1 - Iresine viroid 1; PCFVd - Pepper chat fruit viroid; PSTVd - Potato spindle tuber viroid; TASVd - Tomato apical stunt viroid; TCDVd - Tomato chlorotic dwarf viroid; TPMVd - Tomato planta macho viroid; PospUni - pospiviroid universal assay; PlantIC - plant internal control assay.
c Mean median fluorescence intensity (MFI) values (± standard deviation) are presented for each test in the array.
d Results in bold denote values that exceed the threshold for positivity, whereby thresholds were calculated using the novel non-parametric threshold setting method described in this study.