First report of Sugarcane streak mosaic virus in Iran.
A survey was conducted in Khuzestan province (Iran) to investigate the distribution of sugarcane diseases caused by luteoviruses, poaceviruses and potyviruses. During September to November 2014, symptoms associated with Sugarcane mosaic virus (SCMV), Sugarcane streak mosaic virus (SCSMV) and Sorghum mosaic virus infection were observed in some sugarcane fields. These symptoms included interveinal chlorotic specks, streaks or stripes on the leaves. Symptom-bearing leaf samples were collected, and total RNA was extracted. With the aim of detecting SCSMV, RT-PCR was performed using specific primers designed to amplify 570 bp from the nuclear inclusion B and coat protein gene sequences. Amplified fragments of the expected size were sequenced and a BLASTn search showed more than 90% identity with other isolates (AM749393 and GQ388116). SCSMV was first reported in the USA and subsequently detected in Asia. This is thought to be the first report of SCSMV in Iran. Symptoms were observed on all cultivars surveyed (cp48-103, cp69-62 and cp57-614) and in ∼20% of the area under cultivation. The most severe symptoms were seen on cp57-614 with ∼70% of the leaf area exhibiting symptoms. In addition, these plants were shorter and had smaller stem diameters compared to healthy plants.