Abstract:

Aims To reveal the relationship between rhizosphere microbial composition, functional characteristics and health status of Malania oleifera.

Methods We collected rhizosphere soil samples of healthy and non-healthy M. oleifera at five different habitats in broadleaf forest, artificial planting forest and karst forest, sequenced the microbial communities using illumina high-throughput sequencing techniques and predicted the microbial community functions using FAPROTAX.

Important findings The results showed that: 1) Amplicon sequence variants (ASV) representative sequence classification analysis showed slight differences in microbial composition among five habitats. The top five bacterial phyla were Acidobacteriota, Proteobacteria, Actinobacteriota, Chloroflexi and Myxococcota. There were significant differences in rhizosphere microbial composition between healthy and non-healthy plants, and the dominant microbial taxa changed significantly. 2) The non-metric multidimensional scaling (NMDS) analysis showed significant differences in microbial components of M. oleiferawith different health status. Redundancy analysis results showed that the healthy plant samples were distributed along the first axis, and the two axes explained 25.83% of the variation in the microbial community as a whole. The contents of soil available phosphorus, total potassium and pH were the main factors affecting the rhizosphere microbial communities of healthy plants. Redundancy analysis of non-healthy plants showed that 51.84% of the variation in microbial community was explained by the two ordination axes. Soil total potassium content and available phosphorus content represented the important factors affecting the rhizosphere microbial communities of the non-healthy plants. 3) The correlation heatmap showed that soil pH, available phosphorus content and total potassium content were significantly correlated with the abundance of Chloroflexi, Planctomycetota, Methylomirabilota and Desulfobacterota in healthy plants. However, the abundance of Desulfobacterota, Acidobacteriota, Desulfobacterota, Latescibacterota and Gemmatimonadota were significantly affected by soil pH, available nitrogen content, available phosphorus content, total phosphorus content and total potassium content in non-healthy plants. 4) FAPROTAX functional prediction results showed that the abundance of phototrophy, photoautotrophy, aromatic compound degradation, cyanobacteria and oxygenic decreased significantly in healthy rhizosphere microorganisms, whereas fermentation, ureolysis and human pathogens increased significantly. The results demonstrate that the rhizosphere microbial community undergoes significant changes in different health conditions.

Key words: Malania oleifera, rhizosphere microbe, microbial community, microbial function, high-throughput sequencing techniques