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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]

Objective: To isolate, identify and characterize a new Proteus phage and analyze its genome. Methods: The strains isolated from yak slaughtering in the laboratory were cultured, their DNA was extracted and subjected to 16S rRNA sequencing, and the host bacteria were identified and used for bacteriophage separation from the environmental sewage of a yak slaughterhouse in Chengdu, Sichuan. The bacteriophage was separated and purified by the double-layer agar plate method, and its optimal multiplicity of infection (MOI), one-step growth curve and tolerance were determined. Its morphology was observed by negative staining with phosphoric acid and transmission electron microscopy (TEM). The whole genomic DNA of the phage was extracted using a commercial kit, sequenced on the Illumina MiSeq sequencing platform, assembled, annotated, and genomically analyzed. Results: Totally 10 Proteus strains were identified from the 67 isolates, and one phage with strong lytic activity, named Proteus phage PV66, was isolated from the sewage. PV66 could lyse Proteus and Enterococcus faecalis. The optimal MOI was 0.1. The results of one-step growth curve showed that the incubation period of bacteria infected with PV66 was about 10 min, the lytic period was about 80 min, and the average lytic amount was 321 PFU/cell. The tolerance pH range was 3–12, and the tolerance temperature was 65 ℃. The bacteriophage had a C3 morphotype under electron microscopy, with a head length of (140 ± 1) nm, a width of (54 ± 2) nm, and a tail length of (36 ± 1) nm. The genome sequencing results showed that the whole sequence length of PV66 was 90 492 bp. The phylogenetic tree analysis showed that the phage had high homology with Proteus mirabilis phage and Cronobacter phage and was in the same branch as non-Kuravirus. Conclusion: The Proteus phage has good application potential. This study provides a basis for future development of new bacteriophages, and enriches the database of Proteus phages.

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Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)