Comparative Analyses of Rhizosphere Bacteria Along an Elevational Gradient of Thuja sutchuenensis

Abstract

Thuja sutchuenensis Franch. is an endangered species in southwestern China, primarily distributed in 800–2,100 m of inaccessible mountainous areas. Rhizosphere soil physicochemical properties and bacterial communities play an essential role in managing plant growth and survival. Nonetheless, the study investigating rhizosphere soil properties and bacterial communities of T. sutchuenensis is limited. The present study investigated soil properties, including soil pH, organic matter, water content, nitrogen, phosphorus, and potassium contents, and bacterial communities in nearly all extant T. sutchuenensis populations at five elevational gradients. Our results demonstrated that the increase in elevation decreased rhizosphere and bulk soil phosphorus content but increased potassium content. In addition, the elevational gradient was the dominant driver for the community composition differentiation of soil bacterial community. Proteobacteria and Acidobacteria were the dominant bacterial phyla distributed in the rhizosphere and bulk soils. Co-occurrence network analysis identified key genera, including Bradyrhizobium, Acidicapsa, Catenulispora, and Singulisphaera, that displayed densely connected interactions with many genera in the rhizosphere soil. The dominant KEGG functional pathways of the rhizosphere bacteria included ABC transporters, butanoate metabolism, and methane metabolism. Further correlation analysis found that soil phosphorus and potassium were the dominant drivers for the diversity of soil bacteria, which were distinctively contributed to the phylum of Planctomycetes and the genera of Blastopirellula, Planctomycetes, and Singulisphaera. Collectively, this comprehensive study generated multi-dimensional perspectives for understanding the soil bacterial community structures of T. sutchuenensis, and provided valuable findings for species conservation at large-scale views.

Divergent Fungal Community Dynamics of Thuja sutchuenensis in Arid Environments

“…T. sutchuenensis plants were grown in the Daba Mountain region as previously documented [ 10 , 27 ]. Four sampling sites (i.e., Groups A, B, C, and D) encompassed a broad elevational range of 800 to 2100 m, covering a diverse array of ecological niches for T. sutchuenensis .…”

“…Arid stress profoundly influences plant health and growth, and this is particularly relevant for species like T. sutchuenensis , which demonstrates remarkable resilience under extremely arid conditions [ 7 , 10 ]. Fundamentally, arid lands lead to a scarcity of water, disrupting key plant processes.…”

Contrasting Responses of Rhizosphere Fungi of Scutellaria tsinyunensis , an Endangered Plant in Southwestern China

“…Physical and chemical analyses for soil pH, OM, WC, alkaline nitrogen (AN), and available phosphorus (AP) were conducted as previously reported ( 54 ). Specifically, after standardized treatment, soil WC was determined by drying method; soil pH was determined by potentiometric method; soil OM was measured by potassium dichromate and sulfuric acid digestion method; soil AN was measured by alkali hydrolysis diffusion method; and soil AP was quantified by NaHCO 3 extraction molybdenum antimony resistance colorimetry.…”

Bacterial community shifts occur primarily through rhizosphere expansion in response to subsoil amendments

“…Despite the photosynthetic nature of these bacterial genera, they are recognised as rhizosphere-associated, a trait observed in numerous other enriched bacterial taxa within the plantamendment combination, such as Chitinophagaceae, Rhizobiaceae, Burkholderiaceae, Sphingobacteriaceae, Saccharimonadales, Rhodanbacteraceae and Sphingomonadaceae. (Andersen et al, 2018;Deng et al, 2022;Gopalakrishnan et al, 2015;Hayat et al, 2010;Kisvarga et al, 2023;Luo et al, 2023;Wang et al, 2022;Woli nska et al, 2018;Zuo et al, 2022;Zverev et al, 2020).…”