ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbe and Virus Interactions with Plants
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1655235
First detection of Dickeya fangzhongdai in Italy: double-edged role from virulent on vegetables to potent VOC-mediated anti-Xylella fastidiosa activity
Provisionally accepted
- International Centre for Advanced Mediterranean Agronomic Studies, Valenzano, Italy
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
In this study, we report the first detection of Dickeya fangzhongdai (D. fangzhongdai) in Italy, which was isolated from an asymptomatic cauliflower plant in Valenzano (Apulia region), as part of an effort to isolate antagonistic bacteria against Xylella fastidiosa subsp. pauca (Xfp).Results of the preliminary antagonistic screening showed that one isolate (C7) has a strong activity against Xf on BCYE agar plates. The Illumina whole-genome sequencing and bioinformatic analysis showed that C7 genome consists of a single circular chromosome of 5,045,655 bp in size, with an average nucleotide identity (ANI) exceeding 98% when compared with other D. fangzhongdai strains reported in the GenBank; thereby confirming its taxonomic allocation within the D. fangzhongdai species. Furthermore, multi-locus sequence analysis employing concatenated sequences of the atpD, gyrB, infB, and rpoB genes showed that the strain C7 is phylogenetically close to D. fangzhongdai strain B16 from Slovenia (acc.n°: NZ_CP087226). The strong antagonistic activity of C7 against Xf was also observed under physically separated conditions using a cut agar barrier, suggesting the involvement of volatile antimicrobial compounds (VOCs). Thus, headspace solid-phase microextraction and gas chromatography coupled with mass spectrometry (SPME/GC-MS) analysis revealed that the strain C7 emits 17 distinct VOCs during incubation in YPG broth, suggesting that strain C7 employs VOC-mediated inhibition as a defense mechanism to suppress bacterial competitors.Pathogenicity assessment showed that strain C7 induces severe soft rot in potato tubers, onion bulbs, and pear fruits, as well as, for the first time, causes browning of vascular tissues in cauliflower plants and blackleg in Havana tobacco plants. The prior detection of D. fangzhongdai in the Netherlands and its present identification in Italy on new hosts (cauliflower and tobacco) raise significant concerns about its further establishment, expanded host range, and phytosanitary implications for European agriculture.
Keywords: Bacterial soft rot, Antagonistic Activity, Brassica, Whole-genome sequencing, SPME/GC-MS
Received: 27 Jun 2025; Accepted: 23 Jul 2025.
Copyright: © 2025 Sabri, EL Handi, Mektoubi, Trani, Cara and Elbeaino. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Toufic Elbeaino, International Centre for Advanced Mediterranean Agronomic Studies, Valenzano, Italy
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.