Grape-Derived Peptides to Prevent and Suppress Pierce's Disease
September 10, 2019
A promising new treatment therapy to enhance grapevine immunity to Pierce’s Disease is being developed by researchers in New Mexico. The treatments being studied use grape-derived peptides that can be applied to grapevines infected with Xylella fastidiosa (Xf), the causative bacterial agent of Pierce’s Disease (PD) in grapevines, in order to prevent, suppress or cure PD and increase the productive life of grapevines.
The California Department of Food and Agriculture (CDFA) Pierce’s Disease and Glassy-winged Sharpshooter Board recently approved $448,000 in research funding over two years at a meeting in Sacramento for the researchers to conduct field studies.
The principal investigator for the project is Dr. Goutam Gupta, a scientist specializing in human and plant genome and infectious disease research, who worked for 30 years with Los Alamos National Laboratory (LANL) in New Mexico. He is currently a senior research scientist with the non-profit Biolab of New Mexico Consortium (NMC), founded in 2006, that includes LANL and other New Mexico universities and institutions.
Gupta is also affiliated with Innate Immunity, LLC, a biotechnology startup founded in 2016 in Santa Fe, NM, to develop and commercialize peptide and protein therapies to treat and prevent human and plant diseases. Innate Immunity has invested in the PD peptide technology and helped fund trials and lab work to date.
PD Board research screening committee chair Steve McIntyre, of Monterey Pacific vineyards based in Soledad, CA, presented the research proposal to the full PD Board as an out-of-cycle request from the Board’s normal annual research funding time frame based on encouraging results from recent trials. A goal is to conduct further field trials during the current growing season. McIntyre said, “The science looks good and looks promising. More field trials will test how long the peptide treatment will last in a commercial vineyard environment, and how often it may need to be applied.” The researchers will also look at other peptides for treatment in addition to two already identified and tested.
The PD Board research funds would go to work performed through the NMC Biolab, a private, non-profit entity. The PD Board and CDFA plan to negotiate the research contract as an investment agreement that could ultimately result in royalties to the Board for commercial products arising from the research.
Past and Planned Field Trials
The researchers have selected peptides based on anti-Xf activity, lack of human/plant toxicity, and the ability to overcome bacterial resistance. Recent tests show that these peptides are capable of clearing Xf from infected leaves collected from the field.
A field trial was performed in spring 2019 in Sonoma County in a test plot of 30 vines known to be infected with PD that were scheduled for removal. Topical applications separately testing two different peptides in solutions were applied to woody vine tissue using a spray bottle at a rate of 50 ml per vine. Each vine received three separate applications on different days over the course of a few days. Tissue samples were taken the day after each application and were analyzed for Xf bacteria. Good clearance of Xf bacteria was achieved after one application, and 100 percent clearance was achieved after the second application.
The researchers plan to conduct further California field efficacy studies on the topical delivery of the anti-Xf peptides in collaboration with the industry at sites with high PD pressure and with different temperature and climate profiles. Objectives of the planned field studies are to determine the optimum dose of the application per vine to provide Xf clearance, determine how frequently an application is required, and determine how long it lasts. The research funding will also allow Biolab NMC to look for other grape-derived peptides that provide PD immunity and conduct field trials with those to compare with the efficacy of the two currently identified peptides. It is anticipated that commercial products would be developed as spray materials with application timing to be determined based on trials during the growing season.
McIntyre also called the anticipated research product a “platform technology” that could benefit other crops susceptible to PD, such as citrus, almonds and olives, to possibly expand the commercial benefits and potential royalties from the research investment.
Edgar “Pete” Downs, president of Family Winemakers of California, is acting as an advisor to Innate Immunity and is a wine industry liaison for the research project. Downs previously met Gupta while serving as an industry member of the PD Board in his former capacity as an executive with Kendall-Jackson. At that time, Downs and other wine industry representatives were on a field trip to New Mexico to see if work being done at LANL could help understand and better address PD. When Gupta joined NMC, he contacted Downs and asked for his help as a liaison with the California wine industry. Downs coordinated the Sonoma County field trial earlier this year and helped inform the PD Board about the research proposal.