Abstract:

Objective: In this study, the structure and diversity of rhizosphere bacterial communities in both wild and artificially cultivated Monochasma savatieri Franch ex Maxim. in Jiangxi Province were investigated to explore their relationship with soil physical and chemical properties. The aim of this study is to offer a theoretical basis for further studies on wild-simulated cultivation modes for constructing a healthy rhizosphere microenvironment for M. savatieri. Method: Rhizosphere soil bacteria originating two distinct habitats, the first being natural forests such as Camellia oleifera, Gardenia jasminoides and Pinus massoniana, and the second being artificially cultivated, were selected as research objects. The community structure characteristics of soil bacteria from different habitats were compared and analyzed by using field investigation, Illumina Miseq sequencing, and RDA analysis. Result: The results indicated that there were significant differences in the physico-chemical properties of the rhizosphere soil of M. savatieri between two distinct habitats. The Alpha diversity of artificial bionic cultivation was highest, but there was no significant difference in the alpha diversity among different forest types. In two habitats, Proteobacteria, Acidobacteriota, Chloroflexi and Actinobacteriota were the dominant bacteria phyla. At the genus level, the common dominant genera included Burkholderia-Caballeronia-Paraburkholderia, Bradyrhizobium, Candidatus_Solibacter, Occallatibacter, Bryobacter and uncultured bacterium. There were significant differences in the structure of the bacterial communities between wild and artificial bionic cultivation, with the highest abundance of Proteobacteria in artificial bionic cultivated habitats. The dominant genera unique to wild habitats, including Acidothermus, FCPS473, Conexibacter, Acidibacter, uncultured Acidobacteria_bacterium, uncultured_forest_soil bacterium, all significantly decreased in abundance in the artificial bionic cultivation habitats, while the abundance of dominant bacterial genera unique to artificially cultivated habitats (such as Sphingomonas, Granulicella, Haliangium and Mucilaginibacter), showed a significantly increased abundance in the artificial bionic cultivated habitat. Redundancy analysis (RDA) showed that total nitrogen, available potassium, alkali-hydrolyzable nitrogen, and organic matter were closely related to the composition of soil dominant bacterial communities. Conclusion: There are significant differences in the physico-chemical properties of the rhizosphere soil of M. savatieri between wild and cultivated habitats, as well as significant differences in the structure of bacterial communities. The similarity of the rhizosphere bacterial communities of M. savatieri from different wild habitat conditions is relatively high. The main environmental factors affecting bacterial community structure are soil total nitrogen, available potassium, alkaline nitrogen, and organic matter. This study provides a reference basis for the resource utilization of rhizosphere micoorganisms of M. savatieri.

Key words: Monochasma savatieri, soil bacterial, community structure, habitats