Isolation and characterization of the virulent phage Savoy targeting Xylella fastidiosa subsp. fastidiosa

Isolation and characterization of the virulent phage Savoy targeting Xylella fastidiosa subsp. fastidiosa | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Isolation and characterization of the virulent phage Savoy targeting Xylella fastidiosa subsp. fastidiosa Cuong Hoang, Hajun Lee, Ashley Mansour, Anthony Del Mundo, Vanessa Law, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7304415/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Xylella fastidiosa is a xylem-limited, vector-borne bacterial pathogen that infects a wide range of plant species worldwide, causing severe diseases and substantial economic losses in key crops such as olives, grapes, plums, almonds, and citrus. With few resistant cultivars available, current management strategies rely heavily on chemical control of insect vectors. Here, we report the isolation and characterization of a virulent bacteriophage, Savoy, exhibiting strong lytic activity against the grapevine-infecting X. fastidiosa strain WM1. Transmission electron microscopy identified Savoy as a Siphophage with a long contractile tail. The phage displayed optimal infectivity at a multiplicity of infection of 1 and remained stable across broad temperature (4–45 °C) and pH (3–11) ranges. In vitro assays demonstrated that Savoy effectively lysed planktonic bacterial cells and inhibited biofilm formation. Genome analysis revealed a 61,990 bp genome organized into functional modules associated with DNA metabolism, head and packaging, tail structure, lysis, and connector proteins. No known virulence factors, antimicrobial resistance genes, or CRISPR elements were detected. Multiple genes in Pseudomonas soli Savoy-resistant mutants harbored single nucleotide polymorphisms affecting diverse functional proteins. These findings highlight phage Savoy as a promising candidate for the development of sustainable phage-based biocontrol strategies against X. fastidiosa, with potential to reduce reliance on chemical treatments and mitigate crop losses. Biological sciences/Biotechnology Biological sciences/Microbiology Biological sciences/Plant sciences bacteriophage genome characterization phage receptors Xylella fastidiosa Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryinformationPhageSavoy.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7304415","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":529936325,"identity":"2280bd37-d140-4759-99a8-6deb9aa753a7","order_by":0,"name":"Cuong Hoang","email":"","orcid":"","institution":"University of California, Riverside","correspondingAuthor":false,"prefix":"","firstName":"Cuong","middleName":"","lastName":"Hoang","suffix":""},{"id":529936326,"identity":"ce013c71-1772-4ef8-bfbc-0f12d3b149af","order_by":1,"name":"Hajun Lee","email":"","orcid":"","institution":"University of California, 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