Thaqi Stefanie Katharina, Hensel Natalia, Vitow Nora, Baum Christel, Streb Lisa-Marie, Kublik Susanne, Leinweber Peter, Panten Kerstin, Schloter Michael, Schulz Stefanie
Chair of Environmental Microbiology, TUM School of Life Sciences, Technische Universität München, Emil-Ramann-Straße 2, 85354, Freising, Germany.
Chair of Crop Physiology, TUM School of Life Sciences, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany.
Environ Microbiome. 2025 Jul 21;20(1):92. doi: 10.1186/s40793-025-00751-0.
Non-rhizobial endophytes (NREs) support plant health and nodule function by enhancing symbiotic interactions and nitrogen fixation. However, their recruitment dynamics under fertilizers of varying phosphorus solubility remain poorly understood. This study investigated how four P fertilization treatments-no phosphorus (P0), bone char (BC), surface-modified bone char plus (BC), and triple superphosphate (TSP)-with increasing solubility influence microbial recruitment and diversity in Pisum sativum, leading to differences in plant-available phosphorus across bulk soil, rhizosphere, roots, and nodules.
Using 16S rRNA amplicon sequencing, we found that nodule-associated microbial communities were primarily recruited from unknown sources, likely seeds, followed by roots, especially under BC. Phosphorus solubility of treatments significantly influenced recruitment patterns, with solubility further shaping microbial diversity. BC recruited beneficial taxa like Beijerinckiaceae and Flavobacteriaceae, which are associated with nitrogen fixation and biocontrol. In contrast, the highly soluble TSP treatment expanded recruitment from the rhizosphere, reflecting less stringent environmental filtering and promoting taxa like Steroidobacteraceae and Blastocatellaceae, known for nutrient cycling and pathogen suppression. In the absence of P fertilization (P0), recruitment relied heavily on seeds and roots, with arbuscular mycorrhizal fungi colonization prioritized over nodulation. Notably, TSP supported significantly more nodules with greater microbial diversity, potentially enhanced by NREs.
Phosphorus solubility of the applied fertilizers strongly influences NRE recruitment dynamics in P. sativum. Seeds and roots act as primary reservoirs, while highly soluble fertilizers promote broader recruitment from the rhizosphere and increase microbial diversity in nodules. These results underscore the importance of the fertilization form in modulating NRE recruitment.
非根瘤菌内生菌（NREs）通过增强共生相互作用和固氮作用来支持植物健康和根瘤功能。然而，在不同磷溶解度的肥料作用下，它们的招募动态仍知之甚少。本研究调查了四种磷施肥处理——无磷（P0）、骨炭（BC）、表面改性骨炭加（BC）和重过磷酸钙（TSP）——随着溶解度增加对豌豆微生物招募和多样性的影响，导致在土壤、根际、根和根瘤中植物有效磷的差异。
使用16S rRNA扩增子测序，我们发现与根瘤相关的微生物群落主要从未知来源招募，可能是种子，其次是根，特别是在骨炭处理下。处理的磷溶解度显著影响招募模式，溶解度进一步塑造微生物多样性。骨炭招募了有益类群，如与固氮和生物防治相关的拜叶林克氏菌科和黄杆菌科。相比之下，高溶解度的重过磷酸钙处理扩大了根际的招募，反映出环境过滤不那么严格，并促进了以营养循环和病原体抑制而闻名的类固醇杆菌科和芽孢杆菌科等类群。在不施磷（P0）的情况下，招募严重依赖种子和根，丛枝菌根真菌定殖优先于根瘤形成。值得注意的是，重过磷酸钙支持显著更多的根瘤，且微生物多样性更高，可能受到非根瘤菌内生菌的增强。
所施肥料的磷溶解度强烈影响豌豆中非根瘤菌内生菌的招募动态。种子和根是主要的储存库，而高溶解度肥料促进从根际更广泛的招募，并增加根瘤中的微生物多样性。这些结果强调了施肥形式在调节非根瘤菌内生菌招募中的重要性。
