First report of Wheat streak mosaic virus in Australia

We report that Wheat streak mosaic virus (WSMV) has been identified in Australia. Virus-like symptoms consisting of intermittent chlorotic streaks and mosaic were observed in August 2002 on wheat plants grown in a Canberra research glasshouse. Subsequently, similar symptoms were observed on wheat plants growing at a field site on the outskirts of Canberra. These symptoms were mechanically transmissible to healthy plants and potyvirus-like, flexuous virus particles were observed in symptomatic plants by electron microscopy. RT-PCR primers described for WSMV were used to amplify part of the 3' terminal region of the WSMV genome from diseased plants and showed that there was 98.9% similarity with a type isolate of WSMV. The identity of the virus was confirmed using an ELISA specific for WSMV. Since the first identification from Canberra, WSMV has also been detected at several sites in New South Wales, Victoria and South Australia. A comparison of the nucleotide sequences of a larger region of the genome from five Australian isolates showed that they shared at least 96.9% similarity, and that they were most closely related to USA and Turkish strains of the virus.