Background and Aims: Epipremnum aureum (pothos), a perennial ornamental plant belonging to the family Araceae, is widely cultivated as a decorative houseplant and greenhouse ornamental species. Viral diseases are among the most important constraints affecting the quality, marketability, and propagation of ornamental plants. During a survey conducted in January 2023 in ornamental plant greenhouses in Maragheh, Yazd, Shiraz, Tehran, and Bushehr, Iran, pothos plants showing chlorotic and necrotic spots, yellowing, concentric ringspots, mosaic patterns, and leaf deformation were observed. Because these symptoms were similar to those caused by orthotospoviruses, the present study aimed to investigate the possible natural infection of E. aureum by Tomato spotted wilt virus (TSWV), currently classified as Orthotospovirus tomatomaculae.
Material and methods: Twenty-five symptomatic pothos leaf samples and one asymptomatic sample used as a negative control were collected and subjected to total RNA extraction. Reverse transcription-polymerase chain reaction (RT-PCR) was performed using the degenerate orthotospovirus primer pair Tospo_ GENs/Tospo_GENas, which amplifies a conserved region of the nucleocapsid gene. The amplified fragment was purified and sequenced by Sanger sequencing. The obtained sequence was compared with representative TSWV sequences available in GenBank using BLASTn and phylogenetic analysis.
Results: RT-PCR generated an amplicon of the expected size, approximately 420 bp, from all symptomatic samples, whereas no amplification was observed from the asymptomatic control plant. Sequence analysis confirmed that the amplicon corresponded to TSWV. The Iranian pothos isolate showed high nucleotide identity with previously reported TSWV isolates from other geographical regions, supporting its classification as TSWV.
Conclusions: To our knowledge, this is the first confirmed report of TSWV naturally infecting E. aureum in Iran. The detection of TSWV in pothos highlights the potential role of ornamental foliage plants as reservoirs of orthotospoviruses in greenhouse production systems. Further surveys, vector monitoring, full-genome sequencing, and biological assays are recommended to determine the epidemiological significance of TSWV infection in pothos and its potential risk to nearby ornamental and vegetable crops. |
