Construction of synthetic Fiji virus resistance genes for use in sugarcane : SRDC final report BS86S

Abstract

Fiji disease of sugarcane, caused by Fiji disease fijivirus (FDV), is one of the most important diseases affecting sugarcane in Australia. FDV is a member of the reovirus family and has a multipartite genome consisting of ten segments of double stranded (ds)RNA ranging in size from 1.8 to 4.4 kilobasepairs (KBP). The total genome size of FDV is approximately 30 kbp. Approximately 80% of the fdv genome has now been clones and sequenced. The majority of the FDV segments characterised to date encode a single protein product, indicated by the presence of a single open reading frame (ORF). Two of the segments, 7 and 9, were found to contain two ORFs each and hence encode two proteins. The predicted functions of segments 1, 3, 5, 7, 8, 9 and 10 have been assigned based on homology to equivalent segments in related reoviruses, and\or protein expression studies. A construct containing ORF 1 from segment 9 has been prepared and used to transform the sugarcane cultivars, Q117 and Q124. Transgenic plants have been produced for each of these cultivars and are currently being prepared for challenge experiments with FDV.