Metabolic and physiological effects of antibiotic-induced dysbiosis in citrus

• Published in: Ecotoxicology and environmental safety 2024-11, Vol.287, p.117325, Article 117325
• Main Authors: Ketehouli, Toi, Goss, Erica M., Ascunce, Marina S., Martins, Samuel J.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - toxicity; Bacteria - drug effects; Bacteria - metabolism; Citrus - drug effects; Citrus - microbiology; Citrus greening; Dysbiosis - chemically induced; Metabolomics; Microbiome; Microbiota - drug effects; Oxytetracycline; Oxytetracycline - toxicity; Photosynthesis - drug effects; Plant disease; Rhizosphere; RNA, Ribosomal, 16S - genetics; Soil Microbiology; Streptomycin; Streptomycin - toxicity
• ISSN: 0147-6513; 1090-2414; 1090-2414
• DOI: 10.1016/j.ecoenv.2024.117325

Streptomycin (Str) and oxytetracycline (Otc) are widely used antibiotics to manage bacterial diseases in citrus and other crops. However, their impacts on the rhizosphere bacterial assembly and plant physiology are poorly understood. The aim of this study was to examine the effects of Str and Otc on the physiology (assimilation, transpiration rate, intracellular CO2, and stomatal conductance to water vapor), rhizosphere bacterial assemblages (16S rRNA gene high-throughput amplicon sequencing), and rhizosphere metabolite profiles in healthy Citrus reticulata trees. The results indicated a reduction in photosynthesis after Str and Otc treatments, whereas CO2 outflow stayed constant. Both antibiotics decreased the culturable numbers of bacteria. Analysis of the microbiome showed changes in relative abundance of bacterial groups, specifically Pseudomonas, Agrobacterium, and Streptomyces, in response to the antibiotics. Metabolite profiles changed in streptomycin- and oxytetracycline-treated citrus plants suggesting response to microbe targets or induction of stress responses. This study advances knowledge of antibiotic-driven effects on the rhizosphere microbiome, rhizosphere metabolome, and plant physiology, which is essential for managing plant diseases while safeguarding rhizosphere ecology and long-term plant health. [Display omitted] •Antibiotic application reduced the total number of culturable rhizosphere bacteria.•16S rRNA sequencing revealed alterations in three key beneficial rhizosphere bacteria taxa.•Antibiotic treatment in citrus trees induced a reduction in photosynthesis.•Str and Otc antibiotics triggered distinct metabolic responses in citrus plants.