Microbial Diversity in Rhizosphere Soil of Rhododendron moulmainense with Different Tree Potential in Wutong Mountain of Shenzhen

【Objective】 This study aimed to explore the relationship between the degradation of tree potential of Rhododendron moulmainense and the physical and chemical properties as well as the microbial community structure in the rhizosphere soil in Wutong Mountain of Shenzhen by analyzing the physical and chemical properties and microbial community diversity of the rhizosphere soil. 【Method】 The water content, pH value, organic carbon, total nitrogen, and mineral nitrogen of rhizosphere soil of R. moulmainense trees with different tree potential in Wutong Mountain were analyzed. Additionally, the DNA of rhizosphere soil was extracted, and was used to investigate microbial diversity and community structure using high-throughput sequencing technology. 【Result】 The result showed that there was no significant difference in physicochemical properties of rhizosphere soil among the three tree potentials. A total of 681 807 effective bacterial sequences were detected in rhizosphere soil of three tree rhizosphere, with an average of 79 898 effective bacterial sequences per sample, of which 2 008 OTUs were obtained, belonging to 438 species and 27 phyla. The dominant bacteria were Acideobacteria (36.3%-47.2% ), Proteobacteria (31.2%-32.0%), and Chloroflexi (3.0%-7.7%). A total of 710 302 effective fungal reads were detected, with an average of 79 862 effective reads per sample, which concluded 1 129 OUT clusters, belonging to 489 species and 10 phyla. The dominant fungi were Basidiomycota (49.3%-59.3%), Ascomycota (32.0%-40.8%), Mortierellomycota (1.7%-4.6%). The result of alpha diversity analysis showed that there was no significant pattern in the richness and diversity of rhizosphere soil fungal community among different tree potentials, but the richness and diversity of bacterial community gradually increase with the decline of tree potential, and the greater the difference of tree potential, the more significant the difference of community richness index (Ace, Chao1, PD_whole_tree) (P < 0.05). Beta diversity analysis showed that there was no correlation between bacteria and tree growth. However, fungi were correlated with tree growth. LEfSe analysis showed that there were significant differences in fungal taxa between dominant Rhododendron rhizosphere soil (AR) and inferior Rhododendron rhizosphere soil (DR). The differential microorganisms were mainly Archaeorhizormyces, Phaeosphaeriaceae, Helotiales, Arthrobotrys, Pseudaleuria, and Pyronemataceae. The Helotiales belongs to the root fungus of the azalea plant. 【Conclusion】 There is no difference in soil physicochemical properties among R. moulmainense trees with different growth potentials, indicating that the variation of soil physicochemical properties may not be big enough to affect R. moulmainense, growth potential. The differences in the structure of soil microbial communities are correlated with R. moulmainense, growth potential. © 2021, Editorial Department of Scientia Silvae Sinicae. All right reserved.