New natural host of Tobacco mosaic virus on three cucurbits in Java, Indonesia

Abstract

Abstract Tobacco mosaic virus (TMV) is a newly emerging virus on cucumber in Java. Regardless the importance of TMV on Cucurbitaceae, little is known about the existence of TMV in Cucurbitaceae plants. The study aimed to detect and identify TMV on bitter gourd, ridged gourd, and watermelon. Symptomatic leaves were collected from several cucurbit cultivations at 5 regencies in West Java, Central Java and East Java provinces. The frequency of virus on samples were determined serologically by DIBA method using specific antisera to 6 viruses (CMV, CABYV, PRSV, SqMV, TMV, and ZYMV). Nucleic acid detection was conducted by RT-PCR using universal primer for Tobamovirus followed by DNA sequencing to confirm virus identity. The results revealed that samples were infected by 6 viruses with frequency varied and multiple infections occurred. The frequency of TMV infection ranged from 5.9 to 89.6%. RT-PCR successfully amplified DNA fragment with size ± 800 bp from bitter gourd, ridged gourd, and watermelon. The similarity of coat protein gene among isolates reached up to 100%. These TMV isolates showed highest nucleotide and amino acid similarity with cucumber isolate from Brebes regency and other isolates infecting several different crops from other countries. This is a new report on the existence of TMV on different cucurbit species in the fields.