Institute of Environmental Biotechnology, Graz University of Technology, Petersgasse 12, 8010, Graz, Austria.
Institute of Plant Sciences, University of Graz, Holteigasse 6, 8010, Graz, Austria.
Microbiome. 2019 Jan 29;7(1):13. doi: 10.1186/s40168-019-0624-7.
Arugula is a traditional medicinal plant and popular leafy green today. It is mainly consumed raw in the Western cuisine and known to contain various bioactive secondary metabolites. However, arugula has been also associated with high-profile outbreaks causing severe food-borne human diseases. A multiphasic approach integrating data from metagenomics, amplicon sequencing, and arugula-derived bacterial cultures was employed to understand the specificity of the indigenous microbiome and resistome of the edible plant parts.
Our results indicate that arugula is colonized by a diverse, plant habitat-specific microbiota. The indigenous phyllosphere bacterial community was shown to be dominated by Enterobacteriaceae, which are well-equipped with various antibiotic resistances. Unexpectedly, the prevalence of specific resistance mechanisms targeting therapeutic antibiotics (fluoroquinolone, chloramphenicol, phenicol, macrolide, aminocoumarin) was only surpassed by efflux pump assignments.
Enterobacteria, being core microbiome members of arugula, have a substantial implication in the overall resistome. Detailed insights into the natural occurrence of antibiotic resistances in arugula-associated microorganisms showed that the plant is a hotspot for distinctive defense mechanisms. The specific functioning of microorganisms in this unusual ecosystem provides a unique model to study antibiotic resistances in an ecological context.
芝麻菜是一种传统的药用植物，也是当今流行的绿叶蔬菜。它主要在西餐中被生食，含有各种生物活性次生代谢物。然而，芝麻菜也与一些引人注目的暴发有关，这些暴发导致了严重的食源性人类疾病。本研究采用多阶段方法，整合宏基因组学、扩增子测序和芝麻菜衍生细菌培养的数据，以了解可食用植物部分的本土微生物组和抗性组的特异性。
我们的结果表明，芝麻菜被多样化的、特定于植物生境的微生物群定植。土著叶际细菌群落主要由肠杆菌科组成，它们具有各种抗生素抗性。出乎意料的是，针对治疗性抗生素（氟喹诺酮类、氯霉素类、酚类、大环内酯类、氨基香豆素类）的特定抗性机制的流行程度仅被外排泵分配所超越。
肠杆菌作为芝麻菜核心微生物组的成员，对整个抗性组具有重要意义。详细了解芝麻菜相关微生物中抗生素抗性的自然发生情况表明，该植物是独特防御机制的热点。在这个不寻常的生态系统中，微生物的特定功能为在生态背景下研究抗生素抗性提供了一个独特的模型。
