Identification Of Viruses Infecting Tobacco In Kunming And Green Prevention And Control Techniques Of Tobacco Mosaic Virus

Virus diseases, causing the loss of quality and yield of tobacco leaf, are important constraints to tobacco production. However, there are no efficient control to tobacco virus diseases. This study aims at know about the occurenc and distribution of viruses infecting tobacco in Kunming, Yunnan province, and research the green prevention techniques of Tobacco mosaic virus(TMV).During the tobacco-growning season from2010to2011, the field suvery were conducted in Kunming. The data of field suvery indicated that TMV is a major virus, the disease incidence in some fields is more than90%. Total of318samples showing the symptoms of virial diseases were collected and tested using ELISA. The ELISA results showed13viruses was detected from the collected samples, including TMV, Potato virus Y (PVY), the positive rate of ELISA was11.95%, Cucumber mosaic virus (CMV),0.86%, Tobacco etch virus (TEV),10.40%, Tobacco necrosis virus (TNV),15.85%, Tobacco vein mosaic virus (TVBMV),38.12%, Chili veinal mottle virus (ChiVMV),10.40%, Tomato spotted wilt virus (TSWV),11.32%,Tomato zonate spot virus (TZSV),44.83%, Iris yellow spot virus (IYSV),1.72%, Groundnut yellow spot virus (GYSV),0.86%,Groundnut bud necrosis virus (GBNV),6.03%, and Impatiens necrotic spot virus (INSV),1.72%.The part of ELISA positive samples of TVBMV, ChiVMV, TSWV, TZSV and INSV were further tested using RT-PCR, and sequenced. Sequence analysis indicated that the3'-terminal sequences of TVBMV isolates from Xundian and Yiliang had the highest identities (97%and92.7%at the nucleotide level,98.5%and95.9%at the amino acid level) with the TVBMV Yunnan isolate, The3'-terminal sequences of ChiVMV isolate from Yiliang have the highest identities (84%at the nucleotide level,88.7%at the amino acid level) with the TVBMV India isolate. The N gene seuqences of twenty-one TZSV isolates from four counties had the highest identities (from93.5%and99.6%at the nucleotide level,98.2%and99.3%at the amino acid level) with that of TZSV tomato isolate (NC₀10489). The N gene seuqences of Seven TSWV isolates from four counties had the highest identities (from95.4%and95.8%at the nucleotide level,97%and97.5%at the amino acid level) with that of TSWV tomato isolate (NC₀02051). The N gene seuqences of Two INSV isolates from Shilin had the highest identities (98.4%at the nucleotide level,99.6%at the amino acid level) with that of INSV Phalaenopsis isolate reported by our laboratory.Based on the3'-terminal sequences of ChiVMV, the complete sequences of ChiVMV isolated from Yunnan tobacco was determined to be9724nt long. The complete sequences of ChiVMV isolated from Yunnan tobacco had the highest identiy (93%) with that of ChiVMV chili isolate reported in NCB. To our knowledge, this is first report of the complete sequences of ChiVMV isolated from tobacco.The field trials results show that three antivirial bio-agents including3-acetonyl-3-hydroxyoxindole (AHO), Dry Mycelium of Penicillium chrysogenumP (DMP) and Chitosan, which are organic inducer, had the good effect of control on TMV, the relative contro efficiency is63.22%,87.43%and20.04%, respectively, when AHO and Chitosan were sprayed tobacco seedling for4times every7days after transplanted, DMP was used as the base fertilizer of trasplant. In combination trials, stirred DMP was stirred in nursery substrate as a base transplant fertilizer, then AHO and Chitosan were sprayed before1-2days each time of tobacco leaves cutting, respectively. After transplanted, AHO and Chitosan were sprayed for four times every7days, respectively. Investigation and statistics results indicated that:both the combination of DMP/AHO and the one of DMP/Chitosan had a better control effect on TMV than single. After7weeks of transplanted, the relative control efficiency of DMP/AHO was78.41%, DMP/Chitosan was69.71%. The results showed environment-friendly combination reagent of DMP/AHO had a good control effect on TMV. Using the combination reagent to control TMV will efficiently reduce the application of chemical pesticides, and lowered the tobacco pesticide residues and effectively protected the ecological environment.