Distribution Investigation And Molecular Identification Of Licorice(Glycyrrhiza Uralensis) Isolate Of One Novel Geminivirus

Licorice(Glycyrrhiza L.)is an important medicinal plant and desert vegetation in China.In recent years,due to the increase of dense planting area of licorice,the occurrence of diseases is becoming more and more serious,which not only seriously affects the quality of licorice,but also leads to the decline of licorice production and brings huge economic losses to local growers.However,the research on licorice disease is relatively insufficient,and the related research on virus of licorice has not been reported.The virus of licorice in Xinjiang and Gansu were sequenced by High-throughput sequencing(HTS)and PCR,one kind of geminivirus contigs were gotten from the databases,and its taxonomic status was clarified from the perspectives of genome structure,genetic evolution and so on.The main results are as follows:1.The viral disease investigation of licorice in 7 regions of Xinjiang,including Ili,Kashgar,Aksu,Korla,Altay,Changji and Gansu Minqin,found that the leaves of Xinjiang Changji,Altay,Aksu and Gansu Minqin licorice were obviously curly,and that was more serious,of which the incidence rates in Ili,Aksu and Minqin were as high as 85%,100% and98% respectively.Most of the samples coincided with reported typical curl leaves symptoms of Geminiviridae.Other areas have mild symptoms of curl leaves,and some samples of Ili have no obvious symptoms of viral disease.2.Through high-throughput sequencing of Changji licorice samples with curly,mosaic leaves.BLAST x results showed that there was at least one geminivirus in licorice samples,which was likely to be a new species through sequence homology comparison.Through the detection of a large number of field samples,it was found that there was a correlation between the geminivirus and leaf curl symptoms.The full-length sequence of the virus was obtained by PCR cloned.Its genome structure is two-component,including 2570 nt of DNA-A genome and 2526 nt of DNA-B genome.DNA-A component encodes four open reading frame(ORFs),and DNA-B component encodes two open reading frame(ORFs).The phylogenetic tree building results of MEGA 5.0 showed that the DNA-A component and DNA-B component of Changji isolate were clustered into one branch with bean golden mosaic virus and curl top virus,respectively.The phylogenetic tree building results of amino acid sequence showed that most of them were clustered into one branch with Bean golden mosaic virus(BGMV).Through the above comparison results,it can be preliminarily determined that the Changji isolate of the virus belongs to a new virus of Geminiviridae.In order to facilitate later research and according to the naming rules of the international virus association,we suggest to temporarily named licorice leaf curl-associated vrius(LLCa V).3.Through biological toxicity test and test and observe plant disease characteristics,the virus can be spread by mealworms and aphids at the same time,the host plant species in the field is very broad,common sense of tomatoes,beans,will stripe disease detected purpose,plant symptoms after inoculation compared with healthy plants,plant with a slightly leaf curl,mosaic symptoms after inoculation.In particular,legumes are the most obvious symptoms.Among the legumes,soybean,kidney bean,red bean and mung bean all showed mild leaf curl,wrinkle and yellow vein,among which,the new soybean leaves were accompanied by Mosaic and malformation,and there may be compound infection.