Sugarcane bacilliform virus, Sugarcane mild mosaic virus and Sugarcane yellow leaf syndrome

Abstract

Sugarcane bacilliform badnavirus (SCBV) occurs worldwide in practically all Saccharum officinarum clones and in S. barberi, S. robustum, S. spontaneum, S. sinense, Saccharum hybrids, Rottboellia exaltata, Panicum maximum and Sorghum halepense. SCBV infection is associated with whitish-chlorotic leaf streaking in some S. officinarum clones, but is symptomless in the majority of cases. There is little information on the effects of SCBV infection on the yield of sugarcane. SCBV can be detected by ELISA, immunosorbent EM (ISEM) and polymerase chain reaction (PCR) amplification. Initial experiments indicate that heat treatment and meristem tip culture are ineffective in eliminating SCBV from Saccharum germplasm. Sugarcane mild mosaic virus (SCMMV) is a mealy bug transmitted clostero-like virus that occurs in mixed natural infections with SCBV in S. officinarum, S. robustum, S. sinense and Saccharum hybrids. SCMMV infection occurs in some sugarcane cultivars with field growth disorders. SCMMV is detected most reliably by ISEM. The form of yellow leaf syndrome (YLS) occurring in a number of commercial sugarcane cultivars in Brazil, Florida (USA) and Queensland (Australia) is associated with infection by an aphid transmitted luteovirus-like agent, which has been detected by EM, dsRNA analysis and PCR amplification. Symptoms of YLS include yellowing of the midrib and lamina. The variety SP71-6163 affected by YLS in Brazil shows significant decreases in sugar yield, but similar effects have not been documented elsewhere. It is possible that the form of YLS occurring in Hawaii may have a different cause.