Production of Virus-free Bulblets by Meristematic Tip Culture with Antiviral Chemical in Lilium brownii var. colchesteri

Abstract

Lilium brownii var. colchesteri has unique and ornamental floral characteristics in graceful harmony with flower and anther colors, flower shape, elegant fragrance, and flower color change from yellowish cream to white during anthesis. There are, however, few accessions conserved in Japan up to the present, and they often show abnormally shaped flowers and mosaic leaves seemingly due to virus infection. Virus-free bulblets were established by combining meristematic tip culture and chemotherapy. At initial diagnosis with RT-PCR, Cucumber mosaic virus (CMV), Lily mottle virus (LMoV) and Lily symptomless virus (LSV) were detected from leaf tissues of the mother plants. All regenerated bulblets obtained by meristematic tip culture of the mother plants were still infected by at least one of the viruses. The meristematic tip of the bulblets infected with either LSV or LMoV was selected for subsequent culture with 2,4-dioxohexahydro-1,3,5-triazine (DHT), an antiviral chemical. LSV was eliminated successfully in mericlones from bulblets with LSV, whereas LMoV was not from those with LMoV. The virusfree bulblets were transferred to new medium without DHT, and multiplied by in vitro scaling. They were then acclimated in a phytotron glass room at 20°C. The plants were confirmed to be virus-free after 18-months' acclimation. It was concluded that the combination of meristem tip culture and chemotherapy is practical for producing virus-free plants of L. brownii var. colchesteri.

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

“…Further research showed that after the first stage of meristem tip culture in Lilium brownii 'Colchesteri' infected with LSV and LMoV, the bulbs were infected with at least one of the viruses. In contrast, the second stage of meristem tip culture in a medium containing the antiviral compound 2,4-dioxohexahydro-1,3,5-triazine (DHT) was effective in eliminating LSV but was ineffective in eliminating LMoV (Masuda et al, 2011). Moreover, whereas antivirals DHT and Virazole reduced the LSV and CMV infection rate in a callus culture of L. longiflorum (Xu et al, 2000), they were ineffective in eliminating LMoV from L. longiflorum and L. brownii 'Colchesteri' (Xu and Niimi, 1999;Masuda et al, 2011).…”

Advancements in Lily Viruses Management: Challenges and Solutions in Elimination and Detection

“…However, this method was found to be ineffective in eliminating LSV from L. longiflorum Asiatic hybrids, such as 'Ace' and 'Nellie White' [36]. The above techniques can be used alone or as modified complex therapies [38][39][40]. Moreover, thermotherapy, meristem tissue culture, and chemotherapy techniques can be applied in in vitro culture systems or ex vitro environments [36].…”

“…The use of meristem tissue culture is an important in vitro technique that consists of culturing on a nutrient medium a small (0.1-0.5 mm) piece of tissue removed from apical buds or nodal segments with an axillary bud [35,39]. Research has shown that the probability of obtaining plants without virus infection is inversely proportional to the size of the excised meristem [38].…”

Variability analysis and evaluation for major cut flower traits of F1 hybrids in Lilium brownii var. colchesteri

“…In this context, the objective of breeding in L. brownii var. colchesteri is to produce virus-free hybrids and new cultivars with other desirable cut and pot flower traits (Masuda et al, 2011).…”