Distribution pattern of RNA viruses causing mosaic symptoms and yellow leaf in Indian sugarcane varieties

Abstract

Yellow leaf (YL) caused by Sugarcane yellow leaf virus (SCYLV) and mosaic disease caused by Sugarcane mosaic virus (SCMV) and Sugarcane streak mosaic virus (SCSMV) either alone or in combination are the major viral diseases in India. Detailed studies were taken up on the prevalence of these viruses in varieties originated from 11 different states in the country. Reverse transcription polymerase chain reaction (RT-PCR) assays with specific primers were conducted to detect the viruses from these sugarcane leaf samples. The results showed that 93.44% of varieties are infected with SCSMV, 31.15% with SCMV and 27.87% with SCYLV. Of the 61 varieties, 47.5% were infected with SCSMV alone, 3.28% with SCMV alone and 4.92% with SCYLV alone. However, 21.3% of them had combined infections of SCSMV and SCMV and similarly 16.4% of them had combined infection of SCSMV and SCYLV. About 6.5% had mixed infections of all the three viruses. Overall, the assay results indicated that SCSMV is predominant among the three viruses and it has been found as a major causative virus of sugarcane mosaic. Although YL has become a major disease in recent years its spread among the sugarcane varieties is low as compared to nearly 100% infection of mosaic symptoms in the selected varieties. The present studies established ubiquitous nature of SCSMV infection in sugarcane in different states in the country. Further studies are being carried out to index all the genotypes in the germplasm for the virus infections using multiplex RT-PCR.