The endophytic actinobacteria associated with Artemisia herba-alba (synonym: Seriphidium herba-alba) are highly diverse. This study aimed to illustrate the extent of their differences from the free-living actinobacteria in the surrounding environment. A selection of eighteen actinobacteria inhabiting A. herba-alba were compared with twenty and ten actinobatceria isolates from the surrounding desert and groundwater, respectively, representing six genera. Antagonistic and enzymatic activities, plant growth-promoting traits, and the occurrence of biosynthetic genes were compared among the isolates. Data were analyzed statistically using principal component analysis (PCA) and were visualized using heat map. Endophytic strains showed higher antimicrobial activity and production of plant growth promoters compared to desert and groundwater strains. Polyketide synthase and non-ribosomal peptide synthetase gene clusters were detected at higher frequencies in the endophytic strains (8 and 11 strains, respectively) than the desert strains (1 and 2 strains, respectively). In contrast, both gene clusters were not detected in the groundwater strains. The PCA revealed unique metabolic characteristics of the endophytes. The heatmap clustered the endophytic strains apart from the free-living strains, indicating distinctive qualitative and quantitative bioactivities. Analysis of 16S rRNA genes confirmed the chemotaxonomic identity of all but two strains, with > 94.5% similarity. Six endophytes displayed < 99.5% similarity with their closest type strains, which might indicate species novelty. This study provides an evidence of functional differences and possible species novelty of the endophytic actinobacteria inhabiting A. herba-alba, compared with the free-living species.

与白蒿相关的内生放线菌（同义词：Seriphidium herba-alba）是高度多样化的。本研究旨在说明它们与周围环境中自由生活的放线菌的差异程度。18 种寄生于A.herba-alba 的放线菌的选择分别与来自周围沙漠和地下水的 20 和 10 株放线杆菌进行比较，分别代表 6 个属。比较了分离株之间的拮抗和酶活性、植物生长促进性状和生物合成基因的发生情况。使用主成分分析 (PCA) 对数据进行统计分析，并使用热图进行可视化。与沙漠和地下水菌株相比，内生菌株显示出更高的抗菌活性和植物生长促进剂的产生。在内生菌株（分别为 8 和 11 株）中检测到聚酮化合物合酶和非核糖体肽合成酶基因簇的频率高于沙漠菌株（分别为 1 和 2 株）。相反，在地下水菌株中没有检测到两个基因簇。PCA 揭示了内生菌的独特代谢特征。热图将内生菌株与自由生活菌株分开，表明独特的定性和定量生物活性。对 16S rRNA 基因的分析证实了除两个菌株之外的所有菌株的化学分类学同一性，具有 > 94.5% 的相似性. 六种内生菌与其最接近的类型菌株显示出 <99.5% 的相似性，这可能表明物种新颖性。这项研究提供了与自由生活物种相比，栖息在A.herba-alba的内生放线菌的功能差异和可能的物种新颖性的证据。