Testing for Pierce's Disease in Vitis vinifera and V. labrusca using a Broad Array of PCR Primers

Esha Sharma
Undergraduate (Environmental & Plant Sciences)
Dr. Andrew Gschwend
Horticulture and Crop Science

Xylella fastidiosa is a plant pathogen that colonizes plants using the xylem structures. There have been large economic losses attributed to the presence of X. fastidiosa within crops. The large range of hosts results in many different agricultural farms that have been affected by the presence of the bacteria within the crop trees and plants. It is seen as a causal agent in plants affected by different plant diseases as well. X. fastidiosa has come to be known as Pierce disease in grape. Pierce disease is a problem that affects grape crops and there is yet to be an effective way to identify its presence in crops. This project focuses on the testing of grapevines, specifically one individual from Vitis labrusca, GREM-4, suspected to be infected with X. fastidiosa and an individual from V. vinifera, 'Pinot Noir', for the presence of Pierce disease. The previous research done for analysis of Pierce disease within crops has focused on the identification and amplification on cultures of plant tissues known to be infected with the bacteria. The analysis gave results on the abilities of PCR to be used as a way to isolate and identify the presence of Pierce disease in the grapevine. Primers from previous papers as well as self-designed primers, designed with the genomes available on NCBI, were used for testing. DNA was isolated from the two individuals using the Qiagen Dneasy Plant Mini Kit and tested with the primers. The PCR results showed no bands but primer dimers or non-target amplification using the primers. The experiment was replicated 4 times with identical results. The lack of amplification could suggest the absence of X. fastidiosa within the tested grapevines or the inability for the primers to find enough X. fastidiosa DNA within the samples to amplify. Further testing is needed for finding reliable methodology for high amplification of the trace X. fastidiosa DNA found within grapevines.