Production of virus-free plants of Lilium spp. from bulbs obtained in vitro and ex vitro

In vitro thermotherapy-based methods for plant virus eradication

“…Chemotherapy followed by thermotherapy at 36 °C produced higher frequencies of plants free of ACLSV, ASPV and ASGV than 34 °C [ 36 ]. Similar results were repeatedly found in combining chemotherapy with thermotherapy in potato [ 54 ], garlic [ 55 ] and lily [ 56 ], in thermotherapy followed by shoot tip culture in garlic [ 57 ], horseradish [ 53 ], cassava [ 54 , 55 ], nectarine [ 56 ], plum [ 57 ] and pear [ 58 ], in combining thermotherapy with shoot tip cryotherapy in raspberry [ 26 ] and apple [ 27 ], and in thermotherapy followed by micrografting in Citrus [ 41 , 42 ].…”

“…1’, ‘4’ and ‘14’ ASGV, ACLSV and ASPV 42 °C/34 °C, (day/night), 55 days 20–57 0.5–1.0 NT 100 [ 58 ] Pear ‘Jinshui no. 2’ ASGV ACLSV 35 °C, 40 days 100 0.5 66.7 33.3 [ 61 ] Apricot ‘Bebecou’ Plum pox virus (PPV) 35–37 °C, 20 days NT 1.0–2.0 (meristem), 5.0 cm (Shoot tip) 35 (Meristem), 28 (Shoot tip) 74 (Meristem) 82 (Shoot tip) [ 69 ] Nectarine ‘Arm King’ PPV and prunus necrotic ringspot virus (PNRSV) 35 °C, 2 weeks NT 1.3–2.0 38 86 (PPV) 81 (PNRSV) [ 56 ] Woody species Plum ‘Earliblue’ PNRSV 35–38 °C, 10–12 days 14–71 5.0 NT 100 [ 57 ] Grapevine ‘Napoleon’ Grapevine leafroll-asso ciated virus-3 (GLRaV-3), grapevine fan leaf virus (GFLV) 37 °C/34 °C, (day/night) 1.5 months NT 0.5–3.0 53–80 72–100 (GLRaV-3) 100 (GFLV) [ 79 ] Grapevine ‘Sagrantino’ Grape virus A (GVA) 36 °C, 57 days …”

“…In the study of Bruna [ 52 ] for eradication of onion yellow dwarf virus (OYDV), in vitro shoots of garlic were preconditioned at 30 °C for 7 days and then heat-treated at 38 °C for 38 days. Step-wise increasing temperatures were also used in Prunus fruits such as peach [ 68 ], nectarine [ 56 ] and apricot [ 69 ].…”

“…Survival levels of the heat-treated shoots and virus free frequencies differed from two apple cultivars by thermotherapy followed by shoot tip culture [ 75 ]. Genotype-specific responses were also found in a number of plants including woody species such as Prunus [ 64 ] and Vitis [ 86 ], and herbaceous species such as Allium sativum [ 55 , 87 ], artichoke infected with ALV [ 32 ], Solanum tuberosum [ 29 ], Lilium [ 56 , 88 ], Cynara cardunculus var. scolymus [ 89 ] and Manihot esculenta [ 59 ].…”

“…It is well-known that ELISA-based methods are much less sensitive to detect viruses than PCR-based methods [ 2 , 117 ]. Often, virus-free frequencies analyzed by ELISA-based methods in plants following virus eradication treatments were much higher than by PCR-based ones [ 28 , 36 , 56 , 63 , 72 ]. Reduction of virus titer, but not virus eradication, was frequently found in the plants following virus eradication treatments [ 51 , 119 ].…”