Date of Graduation

Summer 2015

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Wenping Qiu

Abstract

Over 65 viruses are known to infect grapevines, more than any other agricultural crop. Growth, yield, and quality of virus-infected vines suffer, reducing the profitability to grape growers. Therefore, it is critical to identify grape cultivars resistant to these viruses which can be utilized to protect more susceptible varieties from infection. Wine grape cultivar Norton (Vitis aestivalis) and Chambourcin (V. vinifera hybrid), and rootstock St. George (V. rupestris) have been known to be disease tolerant. In the first study, Norton and Chambourcin were infected with Grapevine fleck virus (GFkV), Grapevine leafroll-associated virus 3 (GLRaV-3), Grapevine virus A (GVA), and Grapevine fanleaf virus (GFLV). Norton and V. rupestris ‘St. George' were infected with Grapevine vein clearing virus (GVCV). Testing of virus-infected grapevines for each virus by the polymerase chain reaction (PCR) assays indicated that the three grape varieties are susceptible to the viruses tested, and, therefore, none should be utilized as virus-resistant cultivars. In the second study, a wild V. rupestris ‘Scheele' vine was tested positive for GVCV, which is referred to as GVCV-VRU, marking the first instance this virus has been observed in the native wild V. rupestris population. The whole genome (7,755bp) of the new GVCV-VRU isolate was assembled. Sequence analysis revealed that GVCV-VRU and GVCV-CHA shared 92% nucleotide identity. The discovery of a new GVCV isolate in wild V. rupestris grapevine and its association with vein clearing disease may have important implications for origin and management of GVCV.

Keywords

grapevine, virus, resistance, aestivalis, vinifera, rupestris

Subject Categories

Plant Sciences

Copyright

© Michael Ryan Kovens

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