Date of Graduation

Spring 2023

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Wenping Qiu

Abstract

More than 60 million tons of grapes are produced annually in the world, making them one of the most widely grown fruit crops. Despite grapes’ economic and health benefits, biotic stressors, such as viruses, cause significant loss to the grape and wine industry. One such virus is grapevine vein clearing virus (GVCV) which seriously threatens grape cultivation in the Midwest region of the United States. This virus has caused the removal of seven commercial vineyards since its discovery in 2004. About 34% of Ampelopsis cordata wild vines are infected with GVCV and serve as a primary inoculum for the spread of the virus by grapevine aphids to commercial vineyards. About 40% of grapevine aphids carry GVCV and it takes only a few seconds for grapevine aphids to transmit this virus. However, the presence of GVCV in its vector does not mean automatic transmission to a new host. In a greenhouse study, in which grapevine aphids were fed only on GVCV-infected vines, their transmission efficiency was 28%, but the natural transmission efficiency of GVCV by grapevine aphids is unknown. In this study, I asked two questions: 1) What is the natural transmission efficiency of GVCV by grapevine aphids? 2) Can GVCV be transmitted vertically via seeds? To answer these questions, grapevine aphids were collected from their hosts at native sites and placed onto the leaves of Chardonel grapevines in the greenhouse. One year later, I collected leaf tissue from these Chardonel grapevines and tested them for GVCV by polymerase chain reaction (PCR). Only 3% of the Chardonel grapevines tested GVCV positive, which means grapevine aphids have low natural transmission efficiency of GVCV. I detected GVCV in the seeds of infected grapevines and A. cordata but did not find it in the seedling vines. This indicates that GVCV is seed-borne but not seed-transmitted. Knowledge of the natural transmission of GVCV by grapevine aphids and by seeds helps design strategies to prevent the spread of GVCV to vineyards.

Keywords

plant viruses, badnavirus, seed transmission, grapevine, grapevine vein clearing virus, grapevine aphids, Ampelopsis cordata

Subject Categories

Agricultural Science | Agriculture | Ecology and Evolutionary Biology | Plant Biology | Plant Pathology | Plant Sciences

Copyright

© Matthew Manu

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