As the ancestor of cultivated grape, Vitis vinifera subsp. sylvestris represents a unique, invaluable genetic resource for the improvement of cultivated grapevines. Recently, five populations of wild grapevines were identified in Portugal. Sixty vines were characterized with 11 nuclear SSR markers and further compared with 70 genotypes of Portuguese Vitis vinifera subsp. sativa. The obtained da...

Grapevine degeneration in grapevines caused by Grapevine fanleaf virus (GFLV) has been documented in many viticultural regions worldwide (Andret-Link et al. 2004). It is one of the major economically important virus diseases affecting the longevity of grapevines and reducing the fruit yield and fruit quality. Infected grapevines show a range of foliar symptoms consisting of leaf deformation, ye...

Pierce's disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the ...

Several bacteria were evaluated in greenhouse studies for their effectiveness at preventing formation of galls induced by Rhizobium vitis, the Gram negative bacterium that causes crown gall disease of grapevines. Three endophytic bacteria isolated from Malus domestica yielded promising results and were selected for further examination: Pseudomonas fluorescens isolate 1100-6, Bacillus subtilis i...

Microbial plant endophytes are receiving ever-increasing attention as a result of compelling evidence regarding functional interaction with the host plant. Microbial communities in plants were recently reported to be influenced by numerous environmental and anthropogenic factors, including soil and pest management. In this study we used automated ribosomal intergenic spacer analysis (ARISA) fin...

The objectives of this study were to evaluate the contribution of arbuscular mycorrhizal (AM) fungal hyphae to N uptake from vineyard cover crop litter (Medicago polymorpha), and to examine the soil microbial community under the influence of mycorrhizal roots and extraradical hyphae. Mycorrhizal grapevines (Vitis vinifera) were grown in specially designed containers, within which a polyvinyl ch...

Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), the glassy-winged sharpshooter, is one of the most important vectors of the bacterium, Xylella fastidiosa subsp. piercei (Xanthomonadales: Xanthomonadaceae) that causes Pierce's Disease in grapevines in California. In the present study we report a new method for studying pathogen transmission or probing behavior of H. vitripennis. When...

Introduction An understanding of the seasonal uptake and partitioning of mineral nutrients of grapevines is essential in order to time fertilizer applications. Over the last three decades, several important studies were conducted to determine seasonal nutrition demands of field-grown grapevines and to quantify the partitioning of mineral nutrients (Christensen 1980, Conradie, 1981, Peacock, 198...

Xylella fastidiosa (X. fastidiosa) infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be mi...

Grafting vines as a means of propagation was known as early as the 2 century B.C. (Cato in his treatise De agri cultua.). The use of rootstocks in Vitis, however, was not extensively used until 1880 because it was the only effective method to combat the devastating root louse phylloxera, Phylloxera vitifoliae (Fitch), (Coombe, 1999). In California, grape growers have been using rootstocks for o...