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[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]

[ Purpose] The present paper aimed to study the physical properties, soil enzyme activities and their correlation characteristics of wild Bletilla striata soil in different producing areas in Guizhou, so as to provide a theoretical basis for realizing high yield and quality of B. striata artificial cultivation. [ Method] 8 soil sample plots for the wild B. striata were collected in Guizhou province to detect and analyze the soil physical and enzyme activity index characteristics and the correlation between them. [ Result]The soil density was between 2. 06 -2. 55 g/ cm³ with weak variation. The soil texture was mainly clay loam and sandy loam. In most soils, the proportion of the > 0. 25 mm size soil water-stable aggregates reached 70% . The distribution of the soil water-stable aggregates size fraction were different, 2 - 5 mm size fraction was the dominant size fraction in 4 soil plots, < 0. 25 mm size fraction was the dominant size fraction in 3 soil plots. The dominant size fraction of soil micro-aggregate was 0. 25 -0. 05 mm size fraction. The activities of urease, acid phosphatase and sucrase in soil were significantly different with strong variation. The activities of catalase in soil were not significantly different with weak variation. Soil enzyme activity was strongly influenced by the soil density, soil aggregates and microaggregates. There was a significant positive correlation between urease and acid phosphatase, which could promote each other. [Conclusion] Guizhou wild B. striata has strong adaptability to soil environment. It mainly grows in sandy soil or clay with soil clay content less than 25 %, and some wild B. striata can also grow in clay with soil clay content more than 30% ; Soil specific gravity, soil aggregates and micro aggregates are important factors affecting soil enzyme activity of B. striata. The suitable soil specific gravity is 2. 06 - 2. 55 g/ cm³, the dominant particle size is 2 - 5 mm or < 0. 25 mm, and loam is the best soil texture; Urease and acid phosphatase can promote each other. [ABSTRACT FROM AUTHOR]