Abstract
Rhizosphere microbial communities are of great importance to mediate global biogeochemical cycles, plant growth, and fitness. Yet, the processes that drive their assembly remain unclear. The perennial shrubs Caragana spp., which is well known for their role in soil and water conservation, provides an ideal system to study the biogeography of rhizosphere microorganism communities within natural ecosystems. In order to detect how bacterial rhizosphere communities vary in terms of community diversity and composition, the rhizosphere bacterial community of three Caragana species, Caragana microphylla Lam., C. liouana Zhao, and C. korshinskii Kom., which distributed in arid and semi-arid region of northern China were investigated. Across species, Proteobacteria (61.1%), Actinobacteria (16.0%), Firmicutes (8.6%), Bacteroidetes (3.0%), Acidobacteria (3.5%), Gemmatimonadetes (1.4%), and Cyanobacteria (1.0%) were the most dominant phyla in the rhizosphere of the three Caragana species. The relative abundance of Cyanobacteria was significantly higher in rhizosphere of C. korshinskii Kom. compared with C. microphylla Lam. and C. liouana Zhao, while the opposite was found for Gemmatimonadetes in rhizosphere of C. microphylla Lam. relative to C. liouana Zhao. Stepwise multiple linear regression analysis showed that both diversity and richness of the bacterial rhizosphere communities significantly and positively correlated with soil pH (p < 0.01). Distance-based redundancy analysis indicated that soil properties and non-soil parameters detected there accounted for 47.5% of bacterial phylogenetic structure variation (p < 0.01) all together. Meanwhile, soil total phosphorus accounted for the greatest proportion of community structure variance (9.7%, p < 0.01), followed by electrical conduction (6.5%), altitude (5.8%), soil pH (5.4%), mean annual precipitation (3.6%) and total nitrogen (3.6%, p < 0.05 in all cases). Furthermore, partial Mantel test suggested that bacterial rhizosphere community structure significantly correlated with geographical distance, indicating that the less geographical distant sample sites tend to harbor more similar bacterial rhizosphere community. Our results shed new light on the mechanisms of coevolution and interaction between long-lived plants and their rhizosphere bacterial communities across environmental gradients.
Highlights
Soil is the habitat for a great number of organisms including bacteria, fungi, protozoa, invertebrates, higher plants and animals
Pearson correlation analyses found that most variables including relative humidity (RH), pH, mean annual temperature (MAT), electric conductivity (EC), total nitrogen content (TN), total phosphorus content (TP), and mean annual precipitation (MAP) were significantly changed with altitude increased (Table 1)
The distance-based redundancy analysis was performed to access to what extent the soil properties and nonsoil parameters explain the variance of rhizosphere bacterial community in the three Caragana spp
Summary
Soil is the habitat for a great number of organisms including bacteria, fungi, protozoa, invertebrates, higher plants and animals. These organisms formed complex interaction networks which predominate the functions of the terrestrial ecosystem. Those microbes drive the diverse soil biogeochemical cycles, such as the terrestrial carbon (Bardgett et al, 2008), nitrogen (Stone et al, 2015), and phosphorus cycle (Hilda and Fraga, 1999). The interactions between microbes in the rhizosphere and plants are of great importance to the element of biogeochemical cycling (Philippot et al, 2009), plant nutrition, health, and productivity (de Vrieze, 2015). The rhizosphere microbiome is considered as the second genome to plant condition (Berendsen et al, 2012) and serves on a highly evolved external functional environment for plants (Bais et al, 2006; Lakshmanan et al, 2014)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
