Date of Graduation

Spring 2020

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Wenping Qiu

Keywords

grapevine vein clearing virus, epidemiology, grape aphids, vector, virus transmission, virus, Vitis

Subject Categories

Plant Pathology

Abstract

Grapevine vein clearing virus (GVCV) is an emerging pathogen causing severe damage to cultivated grapevines in the Midwest area of the United States. The prevalence of GVCV has been reported in native Vitis spp. and Ampelopsis cordata, a close relative of vitis in the Vitaceae family, which act as a reservoir for the virus. GVCV can be transmitted from wild A. cordata to Vitis spp. by Aphis illinoisensis (grape aphids) under greenhouse conditions, but the prevalence and transmission in native populations remains unknown. Knowing the prevalence and diversity of GVCV variants in natural grape aphid populations would help monitor and mitigate its impact. In this study, grape aphids from native Vitaceae were collected across the state of Missouri in 2018 and 2019 and conducted diagnostic and genetic analyses. Ten aphids within each community were tested, and GVCV was detected in 91 of the 105 (87%) randomly sampled communities. GVCV was present in 212 of 525 single grape aphids (40%). GVCV variants in grape aphids are genetically diverse and are dispersed across the surveyed region. When comparing the DNA sequences from GVCV isolates from grape aphids and plants, it was found that the same GVCV variants in grape aphids were found in wild and cultivated Vitaceae. The GVCV genome number varied largely in the stylet and body of each individual aphid. These results show that grape aphids carry diverse GVCV variants and contribute to the epidemics of GVCV in wild Vitaceae and vineyards. Our study provides a snapshot of GVCV epidemics and genetic structure that can help implement disease management schemes. Furthermore, the native reservoir, grape aphids, and vineyards form an ideal agro-ecosystem for studying epidemiology, ecology, and the evolution of GVCV.

Copyright

© Adam Louis Uhls

Open Access

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