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Abstract：
Rich endophytic bacterial communities exist in fescue (Festuca ovina L.) and play an important role in fescue growth, cold tolerance, drought tolerance and antibiotic tolerance. To screen for probiotics carried by fescue seeds, seven varieties were collected from three different regions of China for isolation by the milled seed method and analyzed for diversity and motility, biofilm and antibiotic resistance. A total of 91 bacterial isolates were obtained, and based on morphological characteristics, 36 representative dominant strains were selected for 16S rDNA sequencing analysis. The results showed that the 36 bacterial strains belonged to four phyla and nine genera. The Firmicutes was the dominant phylum, and Bacillus, Paenibacillus and Pseudomonas were the dominant genera. Most of the strains had motility (80%) and were biofilm-forming (91.7%). In this study, 15 strains were capable of Indole-3-acetic acid (IAA) production, 24 strains were capable of nitrogen fixation, and some strains possessed amylase and protease activities, suggesting their potential for growth promotion. Determination of the minimum inhibitory concentration (MIC) against the bacteria showed that the strains were not resistant to tetracycline and oxytetracycline. Pantoea (QY6, LH4, MS2) and Curtobacterium (YY4) showed resistance to five antibiotics (ampicillin, kanamycin, erythromycin, sulfadiazine and rifampicin). Using Pearson correlation analysis, a significant correlation was found between motility and biofilm, and between biofilm and sulfadiazine. In this study, we screened two strains of Pantoea (QY6, LH4) with excellent growth-promoting ability as well as broad-spectrum antibiotic resistance. which provided new perspectives for subsequent studies on the strong ecological adaptations of fescue, and mycorrhizal resources for endophytic bacteria and plant interactions.
摘要：
丰富的内生细菌群落存在于羊茅(FestucaovinaL.)中,耐寒性,耐旱性和抗生素耐受性。筛选羊茅种子携带的益生菌，从中国三个不同地区收集了七个品种，通过碾磨种子法进行分离，并分析了多样性和运动性，生物膜和抗生素抗性。共获得细菌分离物91株,根据形态特征，选择36个代表性优势菌株进行16SrDNA测序分析。结果表明，这36株细菌属于4门9属。Firmicutes是主要的门，和芽孢杆菌,假单胞菌属和假单胞菌属为优势属。大多数菌株具有运动性（80％）和生物膜形成性（91.7％）。在这项研究中,15株能够生产吲哚-3-乙酸（IAA），24株具有固氮能力，一些菌株具有淀粉酶和蛋白酶活性，表明了他们促进增长的潜力。对该菌的最低抑菌浓度(MIC)测定表明,该菌株对四环素和土霉素均无耐药性。泛菌（QY6，LH4，MS2）和弯曲杆菌（YY4）对五种抗生素（氨苄青霉素，卡那霉素,红霉素,磺胺嘧啶和利福平)。采用皮尔逊相关分析，发现运动性和生物膜之间存在显着相关性，在生物膜和磺胺嘧啶之间。在这项研究中,我们筛选了两株具有优异的促生长能力和广谱耐药性的泛菌（QY6，LH4）。这为后续研究羊茅强烈的生态适应性提供了新的视角，内生细菌和植物相互作用的菌根资源。
