Detection Of Virus DsRNA In Edible Fungi From Sichuan And Dtermination Of Their Sensitivity To Carbendazim

Edible fungi virus whose genome is dsRNA usually consisting of multi-segmented dsRNA is a part of fungal virus and is latent.In general,edible fungi virus result in no symptom except for mushroom viruses that cause typical out-bursting disease,which bring us trouble for early diagnosis and hidden danger.DsRNA technique gradually developed in fungal virus research was a accurate,convenient and quick method frequently used to detect edible fungi viruses.Carbendazim usually used to restrain mould and then elevate achievement ratio,a kind of benzimidazole fungicide,could inhibit or kill many fungi. However,chemical property of carbendazim is very stable then has long residual period. More and more people begun to worry about its security.In order to get the message of virus dsRNA in edible fungi from Sichuan and then know how to deal,meanwhile to understand the sensitivity to carbendazim of all isolates and Carbendazim residue in fruit body,we conducted the research and collected tube spawn or samples from research institutes and main producing regions in Sichuan province from the year 2006 to 2008.The results of the research as follow:1.A total of 87 isolates were collected to extract dsRNA and then analyze with electrophoresis.The results showed that there were 26 dsRNA-positive isolates existed, the percentage of dsRNA-positive isolates was 29.9%.Among the 26 isolates,there were 16 isolates belonging to Pleurotus ostreatus as 38.1%,9 isolates belonging to Lentinus edodes as 81.8%and 1 scarce mushroom as 11.1%.All other isolates were dsRNA-negtive.2.On behalf of dsRNA-positive isolates,five isolates were chosen to deal with elevated temperature,Cryopreservation and cycloheximide.The results showed that none was transformed to dsRNA-negtive isolate.Yet some changes were observed by comparing the growth rates on PDA after the management in two isolates.3.Among all isolates,60 isolates were used to determined carbendazim sensitivity.The results showed that different breed had different sensitivity by EC₅₀.On PDA,all isolates could normally grow.But on PDA containing carbendazim,all isolates were inhibited except Lentinus edodes and Flammulina velutipes which were not sensitive. The values for 50%effective concentration(EC₅₀) were identified by measuring mycelial growth in fungicide-amended media.EC₅₀ of Pleurotus ostreatus and Agrocybe aegerita were between 12.9～37μg/ml,Agaricus bisporus and Coprinus comatus 3.4～4.07μg/ml and Auricularia auricula 0.12～0.23μg/ml.4.Carbendazim residue in fruit body was analyzed by HPLC,The amounts of residue in three treatments which three rates of Carbendazim,that is 0.05%,0.1%and 0.2%,was added to fruit-body-growing medium were 0.01,0.04 and 0.09μg·g^-1,respectively.