Biodiv Sci ›› 2023, Vol. 31 ›› Issue (4): 22477.  DOI: 10.17520/biods.2022477

Special Issue: 土壤生物与土壤健康

• Original Papers: Microbial Diversity • Previous Articles     Next Articles

The common garden environment and genetic differentiation jointly influence the diversity and community structure of nitrogen-fixing bacteria in the rhizosphere soil of three Caragana species

Lulu Wei1,2, Tingting Xu3, Yuanyuan Li4, Zhe Ai4, Fei Ma1,2,*()   

  1. 1. School of Ecology and Environment, Ningxia University, Yinchuan 750021
    2. Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan 750021
    3. School of Life Sciences, Ningxia University, Yinchuan 750021
    4. School of Geography and Planning, Ningxia University, Yinchuan 750021
  • Received:2022-08-10 Accepted:2022-11-08 Online:2023-04-20 Published:2023-04-20
  • Contact: *E-mail: mafei05@163.com

Abstract:

Aim: Environmental and genetic factors are believed to be the main drivers of variation of plant function traits, which may further influence rhizosphere soil bacteria through root exudates. However, it still remains unclear whether the genetic differentiation would affect the diversity and community structure of nitrogen-fixing bacteria in the rhizosphere soil of plant species.

Method: A common garden experiment was established to examine the diversity and community structure of nitrogen-fixing bacteria in the rhizosphere soil of three Caragana from different provenances by using high-throughput sequencing techniques, which was subsequently correlated with the provenance climates and common garden soil properties to investigate how the environmental factor and genetic differentiation affect the rhizosphere nitrogen-fixing bacterial diversity and community structure.

Result: The present results demonstrated that the rhizosphere nitrogen-fixing bacteria of three Caragana species belonged to 6 phyla, 9 classes, 18 orders, 21 families, 33 genera and 72 species. Proteobacteria, Verrucomicrobia and Cyanobacteria were the main dominant phyla of the three Caragana species of nitrogen-fixing bacteria in the rhizosphere soil, and Mesorhizobium, Azohydromonas and Bradyrhizobium were the dominant genera. There were no significant differences in the diversity and community structure of rhizosphere nitrogen-fixing bacteria among the three Caragana species, but significant differences in the α diversity index between provenances were observed in C. liouana and C. roborovskyi (P < 0.05). The community structure between provenances of C. microphylla and C. roborovskyiwas also significant (P < 0.05). Furthermore, redundancy analysis showed that soil pH of the common garden and mean annual temperature (MAT) of provenance were the dominant factors respectively affecting the diversity and community of rhizosphere nitrogen-fixing bacteria of the three Caragana species.

Conclusion: In summary, our results indicate that the common garden environment and genetic differentiation jointly shape the diversity and community structure of nitrogen-fixing bacteria in the rhizosphere soil of Caragana species. This research can provide important theoretical basis and data support for the ecological adaptation mechanism and introduction and cultivation of Caragana.

Key words: Caragana, common garden, nitrogen-fixing bacteria, diversity and community structure, provenance climate