Study On Transmission Characteristics Of Various Components Of Tobacco Bushy Disease Complex

Tobacco bushy top disease(TBTD)is a fatal disease of tobacco,and it is also the only plant virus disease caused by the combined infection of umbravirus and luteoviridae virus in China.The disease broke out in many tobacco areas in Yunnan province of China,and caused serious economic losses.The virus complex contains five RNA components,the first one is named Tobacco bushy top virus(TBTV),the second one is named Tobacco vein distorting virus(TVDV),the third is named Tobacco vein distorting virus Associate RNA(TVDVaRNA),the third is named Tobacco bushy top virus satellite RNA(TBTV SatRNA)and an unidentified viral RNA.In order to study the pathogenic mechanism of the virus complex and understand the interaction between the various viral RNA components,this article studies from the following aspects:For the first time,the interaction between TVDV,TBTV and its satellite RNA was clarified.The interaction between TVDV,TBTV and TBTV SatRNA was studied in depth by the constructed TVDV,TBTV and TBTV SatRNA Agrobacterium-mediated viral invasive clones.TBTV SatRNARNA in TBTV SatRNA-infected plants(N.benthamiana)could not replicate and systemic infection;the symptoms of TVDV-inoculated plants were not obvious,viral RNA could be replicated and systemic infected and spread by aphids;and plant symptoms of TVDV and TBTV SatRNA were simultaneously inoculated It is not obvious that TBTV SatRNA can not be replicated and infected,and is not transmitted by aphids.At the same time,plants infected with TVDV and TBTV have mild symptoms,and both RNAs can replicate and systemic infection,and can be transmitted from N.benthamiana to flue-cured tobacco through aphids;TVDV,TBTV and TBTV SatRNA,plant yellowing symptoms are more serious,more side branches,but still less than the symptoms of the four known plants,the three viral RNA can replicate and systemic infection,and can be transmitted by aphids.However,the transmission of TVDV and TBTV from flue-cured tobacco to flue-cured tobacco by locusts has not been successful,and all three can be transmitted to flue-cured tobacco when satellite RNA is present.In order to obtain a viral RNA sequence that has not been characterized by the tobacco plexus pathogen virus complex,we have established a method for plant virus identification based on transcriptome deep sequencing technology.The components of viral RNA were studied by deep sequencing using purified tobacco plexus pathogen virus particles.Based on the sequence obtained by deep sequencing,bioinformatics was used to perform sequence annotation screening,candidate sequences were extracted,and candidate sequences were verified by RT-PCR.A plurality of new RNA sequence fragments of reoviridae virus were obtained in the samples,and the above sequences were detected in some plants infected with Tobacco plexus disease,and the sources of the above viruses were also investigated.This study has deepened the understanding of the tobacco plexus pathogen virus complex,enhanced the understanding of the interaction mechanism and propagation characteristics of plant viruses,and provided ideas for the research and prevention of plant diseases caused by the luteoviridae/umbravirus complex.