Studies on Viruses Associated with Red Leaf Symptoms in Washington Vineyards
Author | : Jati Adiputra |
Publisher | : |
Total Pages | : 126 |
Release | : 2017 |
ISBN-13 | : OCLC:1089932461 |
ISBN-10 | : |
Rating | : 4/5 ( Downloads) |
Download or read book Studies on Viruses Associated with Red Leaf Symptoms in Washington Vineyards written by Jati Adiputra and published by . This book was released on 2017 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viral diseases are one of the significant constraints to sustainability of the grape and wine industry that contributes nearly $5 billion annually to Washington State's economy. This study was undertaken to gain a better understanding of grapevine leafroll (GLD) and red blotch (GRBD) diseases causing red leaf symptoms for managing these two virus diseases in vineyards. In the first objective, a large-scale survey was conducted for three growing seasons to assess the prevalence of GRBD and GLD in vineyards. Overall results indicated that Grapevine leafroll-associated virus 3 (GLRaV-3) was more predominant and wide spread than Grapevine red blotch virus (GRBV). The data underscored the critical need for reliable identification of GLRaV-3 and GRBV in vines showing red leaf symptoms and to differentiate virus symptoms from those induced by biotic factors and abiotic stresses. A multiplex PCR assay was developed for the simultaneous detection of GLRaV-3 and GRBV. Phylogenetic analysis indicated the presence of GRBV variants in Washington vineyards that segregated into two well-separated clades. In the second objective, impacts of GRBD were studied in a vineyard field-grafted with cv. Sangiovese showing atypical symptoms of the disease. A comparative analysis between symptomatic vines tested positive for GRBV and non-symptomatic vines negative for GRBV indicated that virus infection can cause significant impacts on shoot biomass, fruit yield and grape quality in field-grafted Sangiovese vines. Since field-grafting results in grafted vines with a blend of characteristics inherited from two distinct types of grapevines, the data provided a foundation for further studies on elucidating the influence of grafting vinifera to vinifera on host-virus interactions. Among the GLRaVs reported earlier from Washington vineyards, very little information is available on the genome characteristics of GLRaV-4 and its strains. In the third objective, the complete genome sequence of GLRaV-4 strains -4, -5, and -9 was determined. The genome sequences of these strains were compared with corresponding sequences of GLRaV-4 and its strains reported from other grapevine-growing regions. Together with sequence information available for GLRaV-1, 2, and -3, the data generated in this objective will provide new avenues for investigating the comparative molecular biology of GLRaVs infecting grapevines.