Endophytic Bacteria Associated with Origanum heracleoticum L. (Lamiaceae) Seeds

• Published in: Microorganisms (Basel) 2022-10, Vol.10 (10), p.2086
• Main Authors: Semenzato, Giulia, Faddetta, Teresa, Falsini, Sara, Del Duca, Sara, Esposito, Antonia, Padula, Anna, Greco, Claudia, Mucci, Nadia, Zaccaroni, Marco, Puglia, Anna Maria, Papini, Alessio, Fani, Renato
• Format: Article
• Language: English
• Subjects: Aleurone layer; Antibiotics; Antiinfectives and antibacterials; antimicrobial compounds; Bacteria; Biodiversity; Endophytes; Environmental aspects; Epoxy resins; essential oil; Ethanol; Expression vectors; Gene sequencing; Genetic aspects; Germination; Herbal medicine; Identification and classification; Localization; Medicinal plants; Metabolic pathways; Metabolism; Metabolites; microbiome; Microbiota; Microorganisms; Microscopy; Oils & fats; Oregano; Origanum; Pathogens; Physiological aspects; phytobiome; Plant bacterial diseases; Plant growth; Secondary metabolites; Seed germination; seed-associated endophytes; Seedlings; Seeds; Transmission electron microscopy
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms10102086

Seed-associated microbiota are believed to play a crucial role in seed germination, seedling establishment, and plant growth and fitness stimulation, due to the vertical transmission of a core microbiota from seeds to the next generations. It might be hypothesized that medicinal and aromatic plants could use the seeds as vectors to vertically transfer beneficial endophytes, providing plants with metabolic pathways that could influence phytochemicals production. Here, we investigated the localization, the structure and the composition of the bacterial endophytic population that resides in L. seeds. Endocellular bacteria, surrounded by a wall, were localized close to the aleurone layer when using light and transmission electron microscopy. From surface-sterilized seeds, cultivable endophytes were isolated and characterized through RAPD analysis and 16S RNA gene sequencing, which revealed the existence of a high degree of biodiversity at the strain level and the predominance of the genus . Most of the isolates grew in the presence of six selected antibiotics and were able to inhibit the growth of clinical and environmental strains that belong to the complex. The endophytes production of antimicrobial compounds could suggest their involvement in plant secondary metabolites production and might pave the way to endophytes exploitation in the pharmaceutical field.