Date of Graduation

Fall 2022

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Wenping Qiu

Abstract

Grapevine vein clearing virus (GVCV), the first DNA virus of the Badnavirus genus discovered in grapevines, is closely associated with grapevine vein-clearing disease. Through earlier research, Koch's postulates were partially met: GVCV was in all diseased plants; GVCV was introduced into a healthy grapevine through grafting and by aphids and caused the disease. However, more shreds of evidence are required to fulfill the last postulate, the same virus must be reisolated from the inoculated diseased grapevine (1). A full-length infectious clone of GVCV was previously constructed to provide evidence; however, its infectivity was not consistent. Therefore, the goal of this thesis research was to increase infectivity. I hypothesized that the low infectivity of GVCV infectious clones is due to virus-induced gene silencing (VIGS) in host plants. It is known that P19 of tomato bushy stunt virus (TBSV) is a viral suppressor of VIGS. I tested the hypothesis by adding TBSV P19 to the agroinfection. I used the agrobacterial strain GV3101 as control, as well as GV3101-LBC, which carries the 1.4 GVCV genome, At-pKYLX7-P19, and At-pKYLX7-GFP. The polymerase chain reaction (PCR) was used for GVCV detection and real-time quantitative PCR was used for qualifying the number of GVCV genomes in plant tissue. The results showed that GVCV effectively infected N. benthamiana. The GVCV genome number was not statistically different in the plants that were agroinfected with GVCV infectious clones with or without the addition of TBSV P19. Therefore, there was insufficient evidence to support that P19 can improve the infectivity of the GVCV infectious clone.

Keywords

grapevine vein clearing virus, infectious clone, virus-induced gene silencing, P19, agroinfiltration

Subject Categories

Plant Pathology

Copyright

© Wen Zhao

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Open Access

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