Co-inoculation with rhizobacterial community and an ectomycorrhizal fungus promotes poplar ectomycorrhization

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 206; p. 105833
• Main Authors: Zi, Haiyun, Wang, Yun, Liao, Yangwenke, Bei, Shuikuan, Zhang, Jinchi, Li, Xiaogang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2025
• Subjects: alpha-Proteobacteria; bacterial communities; Bacteroidia; community structure; ectomycorrhizae; forests; gamma-Proteobacteria; genotype; inoculum; leaves; Microbial interactions; microbiome; Mycorrhiza helper bacteria; mycorrhizal fungi; nitrogen; nutrient uptake; phosphorus; Pisolithus tinctorius; Populus alba; root growth; soil; soil ecology; Symbiotic relationship; Microbial interactions; Symbiotic relationship; Mycorrhiza helper bacteria
• ISSN: 0929-1393
• DOI: 10.1016/j.apsoil.2024.105833

Ectomycorrhizal fungi (ECMF) form symbioses with most forest trees, improving host nutrient uptake and resilience. Studies on the contribution of bacteria to the establishment of these symbioses have used individual bacterial strains, which cannot capture the role of the highly diverse bacterial community in root ectomycorrhization. In this study, two poplar genotypes, Populus alba × P. glandulosa ‘84 K’ and P. davidiana × P. bolleana Loucne were treated with one of three inocula: the bacterial community isolated from poplar plantation soil; the ECMF Pisolithus tinctorius; or both. The ECMF colonization rate of the poplar roots, nutrient accumulation, and leaf and root growth were monitored. Furthermore, we analyzed the rhizobacterial communities of poplar with or without ectomycorrhizae (ECM). The results showed that co-inoculation with the bacterial community significantly increased the ECMF colonization rate in both poplar genotypes by more than threefold compared with inoculation with ECMF alone. The enhancement of poplar ECMF colonization favored phosphorus and nitrogen accumulation in the plant and shoot growth. The rhizobacterial community composition of ECM poplar was difference in both poplar genotypes, implying the important role of host genotype in the tripartite interaction of plant-ECMF-bacterium. Significantly, a core microbiome (43 amplicon sequencing variants, ASVs) associated with enhanced poplar growth was identified across the two genotypes inoculated with ECMF. These ASVs were classified into 30 bacterial families and 35 genera, primarily belonged to Gammaproteobacteria (12 ASVs), Alphaproteobacteria (10 ASVs), and Bacteroidia (7 ASVs). These results highlight the collaborative role of plant-associated microbial communities in establishing plant mycorrhizae. •Bacterial community promotes poplar root ectomycorrhization.•Ectomycorrhization enhances nutritional access of poplar and plant growth.•Poplar genotype has stronger effect on rhizosphere bacteria than ectomycorrhization.•A core microbiome is identified with positive effects on ectomycorrhization.