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Studies on Viruses Associated with Red Leaf Symptoms in Washington Vineyards

2017
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Release : 2017
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Book Synopsis Studies on Viruses Associated with Red Leaf Symptoms in Washington Vineyards by : Jati Adiputra

Download or read book Studies on Viruses Associated with Red Leaf Symptoms in Washington Vineyards written by Jati Adiputra. This book was released on 2017. 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.

Studies on Cost Analysis of Viral Diagnostics and Red Leaf Symptoms in Grapevines

2019 Grapes
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Release : 2019
Genre : Grapes
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Book Synopsis Studies on Cost Analysis of Viral Diagnostics and Red Leaf Symptoms in Grapevines by : Kaitlin McKenzie Hadaway

Download or read book Studies on Cost Analysis of Viral Diagnostics and Red Leaf Symptoms in Grapevines written by Kaitlin McKenzie Hadaway. This book was released on 2019. Available in PDF, EPUB and Kindle. Book excerpt: Grapevines (Vitis vinifera) are extensively cultivated worldwide for the production of wine grapes, table grapes and raisins. Consequently, vinifera grapevines are exposed to a myriad of biotic and abiotic constraints affecting vine health and reducing fruit yield and quality. Among the biotic constraints, viruses such as Grapevine leafroll-associated virus 3 (GLRaV-3) and Grapevine red blotch virus (GRBV) are considered economically important and affecting sustainability of vineyards in Washington State. Unlike white-fruited wine grape cultivars, red-fruited cultivars display leaf reddening or red leaves as a general response to not only infections with GLRaV-3 and GRBV, but also to certain biotic and abiotic stress factors. Although diagnostic assays are available to differentiate red leaf symptoms due to viral infections from those induced by abiotic and biotic stress factors, large-scale testing of grapevines is becoming costly and unsustainable for growers to utilize diagnostic methods in disease management strategies. As testing vines is a crucial component to manage viral diseases in vineyards, a project was initiated to estimate the costs associated with testing for GLRaV-3 and GRBV by molecular diagnostic methods under non-commercial settings. The results presented in this study showed that employing a simplified sample preparation protocol in combination with molecular diagnostics assays can reduce the cost burden of virus testing benefiting growers and other end users. In a second project, studies were conducted to compare biochemical components of red leaves in certain red-fruited cultivars produced due to viral infections, mite herbivory, and mechanical damage to shoots. These leaf samples together with controls were analyzed for pigments (chlorophylls, carotenoids and anthocyanins) and carbohydrates (glucose, fructose, and sucrose) using appropriate analytical methods. The results indicated overall reduction in chlorophyll and carotenoids and accumulation of anthocyanins and carbohydrates in leaves showing red leaf symptoms induced by biotic and abiotic stressors compared to green leaves from healthy vines. The data obtained in this study laid a foundation for future studies to better understand underlying causes and consequences of red leaf symptoms produced by distinct stress factors.

Grapevine Viruses: Molecular Biology, Diagnostics and Management

2017-07-05 Science
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Release : 2017-07-05
Genre : Science
Kind : eBook
Book Rating : 069/5 ( reviews)

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Book Synopsis Grapevine Viruses: Molecular Biology, Diagnostics and Management by : Baozhong Meng

Download or read book Grapevine Viruses: Molecular Biology, Diagnostics and Management written by Baozhong Meng. This book was released on 2017-07-05. Available in PDF, EPUB and Kindle. Book excerpt: The domestication of grapes dates back five thousand years ago and has spread to nearly all continents. In recent years, grape acreage has increased dramatically in new regions, including the United States of America, Chile, Asia (China and India), and Turkey. A major limiting factor to the sustained production of premium grapes and wines is infections by viruses. The advent of powerful molecular and metagenomics technologies, such as molecular cloning and next generation sequencing, allowed the discovery of new viruses from grapes. To date, grapevine is susceptible to 64 viruses that belong to highly diverse taxonomic groups. The most damaging diseases include: (1) infectious degeneration; (2) leafroll disease complex; and (3) rugose wood complex. Recently, two new disease syndromes have been recognized: Syrah decline and red blotch. Losses due to fanleaf degeneration are estimated at $1 billion annually in France alone. Other diseases including leafroll, rugose wood, Syrah de cline and red blotch can result in total crop loss several years post-infection. This situation is further exacerbated by mixed infections with multiple viruses and other biotic as well as adverse abiotic environmental conditions, such as drought and winter damage, causing even greater destruction. The book builds upon the last handbook (written over twenty years ago) on the part of diagnostics and extensively expands its scope by inclusion of molecular biology aspects of select viruses that are widespread and economically most important. This includes most current information on the biology, transmission, genome replication, transcription, subcellular localization, as well as virus-host interactions. It also touches on several novel areas of scientific inquiry. It also contains suggested directions for future research in the field of grapevine virology.

Effects of Red-leaf Disease on Cabernet Sauvignon at the Oakville Experimental Vineyard and Mitigation by Harvest Delay and Crop Adjustment

2011 Grapes
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Release : 2011
Genre : Grapes
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Book Synopsis Effects of Red-leaf Disease on Cabernet Sauvignon at the Oakville Experimental Vineyard and Mitigation by Harvest Delay and Crop Adjustment by : Benjamin L. Calvi

Download or read book Effects of Red-leaf Disease on Cabernet Sauvignon at the Oakville Experimental Vineyard and Mitigation by Harvest Delay and Crop Adjustment written by Benjamin L. Calvi. This book was released on 2011. Available in PDF, EPUB and Kindle. Book excerpt: Grapevines with foliar symptoms similar to leafroll or corky bark infections, but testing negative for the presence of known grape viruses, are often referred to as having "red-leaf" disease. In 2008, a block at the Oakville Experimental Vineyard in Napa Valley, California was observed to express symptoms fitting this description. The progression of red-leaf symptoms was mapped in 2008 and 2009 identifying symptomatic and asymptomatic vines. In 2010, this study aimed, firstly, to determine if Cabernet Sauvignon grapevines with red-leaf disease also expressed delayed maturation symptoms characteristic of the above viruses, and secondly, to test if those symptoms could be mitigated by harvest delay or crop adjustment. Effects of this red-leaf disease on both vegetative and fruit components were observed. Fruit on vines with red-leaf symptoms showed reduced sugar accumulation of 2.3 Brix compared to healthy controls, and the severity of red-leaf symptoms was directly correlated to a reduction in Brix. Photosynthesis, stomatal conductance, pruning weight, berry weight, and berry anthocyanin levels were also lower in diseased vines. Reduced sugar accumulation was somewhat mitigated by delaying harvest and adjusting crop to 50%, with early thinning having a greater impact than late thinning. When imposing a desired sugar level of 25 Brix, harvest was delayed in the early thinned, late thinned, and fully cropped diseased vines by 6, 9, and 15 days, respectively. Midday leaf water potential, juice acidity, and pH were unaffected by red-leaf symptoms or mitigation treatments. A lower ratio of leaf: petiole potassium and higher berry potassium levels in diseased vines support the theory of vascular blockage at the leaf-petiole boundary, and both translocation of solutes as well as berry metabolism appear to be affected by the suspected viral pathogen.

Molecular Biology and Epidemiology of Grapevine Leafroll-associated Viruses

2016
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Release : 2016
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Book Synopsis Molecular Biology and Epidemiology of Grapevine Leafroll-associated Viruses by : Bhanu Priya Donda

Download or read book Molecular Biology and Epidemiology of Grapevine Leafroll-associated Viruses written by Bhanu Priya Donda. This book was released on 2016. Available in PDF, EPUB and Kindle. Book excerpt: Studies were conducted on molecular biology and epidemiology of grapevine leafroll-associated viruses infecting wine grape (Vitis vinifera) cultivars in Washington State. In the first objective, the complete genome sequence of two isolates of Grapevine leafroll-associated virus 1 (GLRaV-1, genus: Ampelovirus, family Closteroviridae ) was determined to be 18,731 and 18,946 nucleotides. The genome of GLRaV-1 isolates contain nine open reading frames with long 5' and 3' non-translated regions (NTRs). The sequence differences in the 5'NTR was used to develop a restriction fragment length polymorphism assay for distinguishing GLRaV-1 variants in vineyards. Northern blot hybridization revealed the presence of three of the eight putative 3' co-terminal subgenomic (sg) RNAs at higher levels in virus infected grapevine samples. The 5' termini of five sgRNAs were mapped and their leader sequences determined. The results provided a foundation to further elucidate the comparative molecular biology of grapevine-infecting members of the family Closteroviridae..

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