Virus Detection And System Construction To Obtain Virus-Free Lilium Davidii Var. Unicolor

Lilium davidii var.unicolor is a famous edible sweet lily in China,which is a variety of Lilium davidii.In recent years,the planting area of L.davidii var.unicolor has been expanding in China.The accumulation of virus diseases has become more and more serious due to long time asexual reproduction,which lead to serious reduction of bulb quality and yield.In this study,leaves and central buds of L.davidii var.unicolor were selected as materials to screening optimal induction culture medium for different explants.A set of RT-PCR amplification system was optimized for detection of cucumber mosaic virus（CMV）and lily saprophytic virus（LSV）simultaneously.Furthermore,a system was constructed to obtain virus-free plant for CMV and LSV infected plant,respectively.This study provided theoretical support for effective control of virus diseases in L.davidii var.unicolor,which is a key for bulb renewal and the improvement of bulb quality and yield.The results are as follows:1.Screening of culture medium for leaf and central bud of L.davidii var.unicolor.The optimal induction medium for leaves was MS+6-BA（2.5 mg/L）+NAA（0.5 mg/L）with a sterilization time of 1 min.The differentiation induction need more than 40days,and the differentiation rate was 53.33%.The optimal medium for central bud induction was MS+NAA（1.0 mg/L）+2,4-D（1.5 mg/L）with a sterilization time of 5min.The differentiation induction need only10 days,and the differentiation rate was78.33%.2.Detection of viruses in L.davidii var.unicolor.Primer combinations（H3F/H3R and W₁F/W₁R）were designed according to coat protein sequence of CMV and LSV.Both CMV and LSV were successfully detected in bulbs and leaves of L.davidii var.unicolor.The detection system was validated by ELISA with 100%detection rate.3.System construction of obtaining virus-free plant from CMV infected L.davidii var.unicolor.When leaves were used as material,heat treatment combined with ribavirin（40℃1d+8 mg/L）presented a better effect to get rid of CMV.The rate of virus-free plant was the highest（88%）and the survival rate was 41.6%.When the central bud is used as material,heat treatment 38℃5d combined with ribavirin10mg/L showed a better effect to get rid of CMV.The rate of rate of virus-free plant was 70%and the survival rate was 86.6%.4.System construction of obtaining virus-free plant from LSV infected L.davidii var.unicolor.When leaves were used as material,heat treatment combined with shoot tip culture（38℃1d+0.4-0.6mm）was better effect to get rid of LSV than other treatments.The highest rate of virus-free plant（82%）was observed in this treatment,and the survival rate was 28.3%.When central bud was used as material,the shoot tip culture combined with heat treatment（0.4-0.6mm+38℃1d）could achieve a better effect to obtain virus-free plant,in which the rate of virus-free plant was 74%and the survival rate was 41.6%.