Purpose The species and distribution characteristics of tobacco viruses diseases in the Jinsha River Basin of Lijiang were clarified to provide a theoretical basis for disease prevention and control.
Methods A total of 53 tobacco plant samples exhibiting evident symptoms of viral diseases were collected from various tobacco-growing regions. The abundance of each virus genus was analyzed by macro virus group sequence techniques, and a genetic phylogenetic tree was constructed. Scanning electron microscopy was further employed to observe the morphology of the viruses, thereby investigating the occurrence of viral diseases in these tobacco-growing areas.
Results The results of macro virus group sequence analysis showed that: on the level of genus, the abundance of Potyvirus, Cucumovirus and Orthotospovirus in the samples from Huaping County (S1) were found to be 66.08%, 20.83% and 5.91%, respectively; in the samples of Yulong Naxi Autonmous County (S2), Orthotospovirus was accounting for 97.20%; in the samples of Ninglang Yi Autonmous County (S3), Potyvirus and Orthotospovirus had abundances of 96.29% and 2.20%, respectively. The phylogenetic tree showed that: potato virus Y (PVY), tomato spotted wilt virus (TSWV), and cucumber mosaic virus (CMV) were detected in sample S1, TSWV was detected in sample S2, and PVY and TSWV were detected in sample S3. The electron microscopy confirmed the presence of linear virions with a diameter of 10-15 nm and length of 700-900 nm, as well as two types of spherical virions: non-enveloped (25-30 nm in diameter) and single-enveloped (80-120 nm in diameter). The results of macro virus group sequence analysis, phylogenetic tree and electron microscopy were consistent. The field investigation indicated an incidence of 42.34%-68.25% for PVY, 12.59%-26.52% for TSWV, and 29.27%-72.31% for CMV in Huaping County; 5.66%-20.34% for TSWV in Yulong County; and 19.18%-36.27% for PVY and 1.08%-4.92% for TSWV in Ninglang County.
Conclusion The main types of tobacco viruses prevalent in the tobacco-growing regions in the Jinsha River Basin of Lijiang include TSWV, PVY and CMV, with TSWV and PVY being the most extensive and widespread.
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