Xanthomonas citri subsp. citri requires a polyketide cyclase to activate the type III secretion system for virulence

• DOI: 10.1186/s12866-025-03749-3
• Publication Date: 2025-02-01T05:16:31Z
• Authors: Shuying Zhu; Siyu Wu; Yanmin Liu; Zaibao Zhang; Huasong Zou
• Keywords: Xanthomonas citri; Xanthomonas; Parasitology

Xanthomonas citri subsp. is the causal agent of citrus canker, which causes substantial losses in production. Here, we report role a polyketide cyclase (PKC) on virulence X. citri. The structure PKC was precisely predicted using Alphafold3. Promoter GUS fusion constructs and real-time quantitative reverse transcription (qRT-PCR) were employed to study pattern expression gene. A deletion mutation created explore metabolic change. determined have signal peptide, START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC (SRPBCC) domain, GyrI-like small molecule binding domain. gene induced planta, as well under stress by CuSO4 SDS. An in-frame resulted loss hosts, restored SRPBCC Furthermore, there remarkable reduction type III genes, such hrpG hrpX. In mutant carrying pkc deletion, ketoleucine acetone cyanohydrin downregulated, four metabolites, including D-ribose, creatine, polyoxyethylene dioleate, cohibin C, upregulated. overall data indicate that affects bacterial modulating secretion system, possibly through biosynthesis particular metabolites.