Molecular Characterization of an Isolate of Tobacco Streak Virus Naturally Infecting Areca catechu L. in China—A First Case in the Family Arecaceae

Tobacco streak virus (TSV) has a wide range of natural host plants, yet it has not been detected in plants of the Arecaceae family. In Hainan, China, areca plants exhibited yellow-green chlorotic streaked leaves, and irregular chlorotic patches appeared on the main stem, which collectively represents typical TSV-infection symptoms. In this study, the near-complete genome sequence of the TSV A6-5 isolate was obtained through meta-transcriptome sequencing combined with reverse transcription polymerase chain reaction (RT-PCR). Molecular characterization indicated that its RNA1 (3435 nt), RNA2 (2841 nt), and RNA3 (2193 nt) shared 99.27%, 99.16% and 98.40% nucleotide sequence identity, respectively, with the previously documented TSV DSMZ PV-0612 isolate from Rudbeckia sp. in Germany. No recombination signals were detected in the RNA1, RNA2, and RNA3 sequences of the TSV A6-5 isolate using all algorithms embedded in RDP5, indicating the isolate is highly evolutionarily conserved. Furthermore, phylogenetic analyses based on the full-length sequences of RNA1, RNA2 and RNA3 collectively verified that the TSV A6-5 is most closely related to TSV DSMZ PV-0612. This study documents the first case of natural TSV infection in Areca catechu L. worldwide and provides a theoretical foundation for the monitoring and control of TSV in areca palm production.