Melon is one of the most popular fruits worldwide and has been bred into various cultivars. RNA-sequencing using healthy melon fruit was performed to determine differences in gene expression among cultivars. Unexpected RNA-seq results revealed that viruses asymptomatically infected fruits at a high frequency (16 of 21 fruits examined were infected) and that viral transcripts highly accumulated in comparison with host transcripts (15 %–75 % of total reads). Their nucleotide sequences and phylogenetic analyses indicated that more than 10 novel isolates of tobacco ringspot virus (TRSV) were found in melon fruits. Asymptomatic infection with TRSV on melon fruits was confirmed by both immunoblot and RT-PCR analyses. Numerous isolates of TRSV generated and maintained in melon fields, and this is likely due to their asymptomatic infections. This TRSV melon isolate infected Nicotiana benthamiana plants with stunting and yellowing symptoms. This is the first report of frequent and asymptomatic infection of TRSV in consumable melon fruits.

甜瓜是世界上最受欢迎的水果之一，并被培育成各种品种。使用健康的甜瓜果实进行 RNA 测序以确定品种间基因表达的差异。出乎意料的 RNA-seq 结果显示，病毒无症状感染水果的频率很高（检查的 21 个水果中有 16 个被感染），并且与宿主转录本相比，病毒转录本高度积累（占总读数的 15%–75%）。他们的核苷酸序列和系统发育分析表明，在甜瓜果实中发现了 10 多个新的烟草环斑病毒 (TRSV) 分离株。通过免疫印迹和 RT-PCR 分析证实了甜瓜果实上的 TRSV 无症状感染。许多 TRSV 分离株在瓜田中产生和维持，这可能是由于它们的无症状感染。具有发育迟缓和变黄症状的本氏烟草植物。这是第一次报道食用瓜果中出现TRSV频繁且无症状的感染。