Whole-Genome Sequences of Tobacco Mosaic Virus (TMV, Tobamovirus tabaci ) Reveal Its Population Genetic Structure and Transmission Routes in China

Viral diseases severely threaten agriculture, particularly in cigar tobacco. Here, we clarified the occurrence and distribution of viral diseases in cigar tobacco in Hainan, China, and identified TMV and CMV as the predominant viruses. Furthermore, we obtained the full-length genomes of two TMV isolates, analyzed their structures and variations, and validated their pathogenicity. Using whole-genome resequencing data from 79 TMV isolates collected over the past two decades─60 from five major tobacco-growing regions of China and 19 from other countries─we constructed a genome-wide SNP data set and analyzed the population genetics and transmission routes. Results indicated that TMV in China originated in northern China and spread via two independent routes: (i) progressive north-to-south spread to the middle and lower reaches of the Changjiang River basin and (ii) direct introduction to Hainan Island. Our study provides insights into viral disease management in the development of the cigar industry.