Search

[Objective] The present paper aimed at determining the occurrence of chilli veinal mottle virus (ChiVMV) in tobacco in Guizhou and the genetic evolution relationship between the ChiVMV strains in Guizhou and in other provinces in China, so as to provide a basis for formulating scientific and reasonable prevention and control measures. [Method] 80 tobacco leaf samples suspected of virus infection were collected from the tobacco fields of Guiyang, Zunyi, Anshun and Tongren in Guizhou province, showing the symptoms of leaf mottling, wrinkling, necrosis and mosaic. Multiple viral primers were designed to detect the collected samples by RT-PCR method, and the detected ChiVMV was further amplified by PCR to obtain the whole genome sequence of Guizhou tobacco ChiVMV. Based on all ChiVMV genome sequences published by NCBI, sequence consistency analysis was performed and phylogenetic evolutionary tree was constructed to study the genetic evolutionary relationship of Guizhou ChiVMV tobacco isolates. [Result] The results of RT-PCR showed that the detection rate of ChiVMV was 37. 50%, the detection rate of tobacco mosaic virus (TMV) was 48. 75%, and the detection rate of potato virus Y (PVY) was 35. 00%. The detection rate of cucumber mosaic virus (CMV) was only 8. 75%. Four complex infection types TMV + PVY, PVY + ChiVMV, PVY + CMV and ChiVMV + PVY + TMV were detected, and the detection rates were 26. 25%, 6. 25%, 10. 00% and 3. 75%, respectively. Guizhou tobacco isolate ChiVMV-GZ (GenBank: OP589298) was obtained by PCR. Sequence consistency analysis showed that ChivMV-GZ was identical with tomato isolates from Sichuan (KC711055) and Sichuan tobacco isolates (MK405594) with high sequence consistency (98. 70% and 98. 50%). Phylogenetic tree was constructed and it found that ChivMV-GZ clustered with ChiVMV strains from Sichuan and Yunnan. [Conclusion] The damage of ChiVMV in Guizhou tobacco has been increasingly serious and sufficient attention should be paid. ChiVMV-GZ was isolated from Guizhou tobacco and amplified to obtain the whole genome of the virus in the study. Based on genetic evolution analysis, it was found that ChiVMV-GZ was most closely related to ChiVMV strains from Sichuan and Yunnan. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to provide a reference basis for the safe production in tobacco fields with medium risk of Cd pollution and remediation, the uptake of Cd by tobacco and its distribution pattern in the whole plant were studied. [Method] The tobacco planting soil with medium risk of Cd pollution was selected for pot experiments to explore the remediation potential of 5 tobacco varieties for Cd in the contaminated soil and safety production about of tobacco. [Result] The concentrations of Cd（1.510-2.110 mg/kg) in 5 tobacco varieties were far less than the limit value of Cd（5.0 mg/kg) in Guizhou tobacco leaves. The order of Cd concentration of 5 tobacco varieties was as follows: Guiyan 8 > Yunyan 87 > CF225 > Nanjiang 3 > Bi’na 1.The Cd concerntration of Guiyan 8 was significantly higher than others. There were no significant difference between Bi’na 1 and Nanjiang 3, and they were significantly lower than others. All of 5 tobacco varieties had strong enrichment ability for Cd（127.695%-204.549%), and the order of enrichment ability was as follows: Bi’na 1>Yunyan 87>CF228>Guiyan 8>Nanjiang 3. The accumulation of Cd in Bi’na 1 had 583.102 μg/plant and the remediation efficiency of Cd in soil was 4.113%, more than 4 other tobacco varieties（2.269%-3.262%). The Cd of Bi’na 1 was mainly stored in the unusable parts such as roots, stems and leaf veins in the tobacco. The distribution rate of Cd in leaves of Bi’na 1 was the lowest with 41.03% concentration, which was lower than that of other tobaccos（above 50%). Bi’na 1 reduced the adverse factors（Cd concentration and distribution rate) in the tobacco production. [Conclusion] Among 5 tobacco varieties, Bi’na maximum accumulation amount of Cd, which mainly exists in unusable part, including root, stalk, leave vein, etc. Compared with other four tobacco varieties, Bi’na 1 reduces the disadvantages during tobacco production. Hence, Bi’na 1 has the potential for safe utilization and restoration of tobacco field medium-polluted by Cd. [ABSTRACT FROM AUTHOR]