Abstract:

【Objective】This work aims to explore the effect of root-associated bacterial microbiomes on the quality of Polygonum cuspidatum by analyzing the correlation between the bioactive compounds and microbiomes. 【Method】The bulk soil, rhizosphere soil and roots of P. cuspidatum in the first, second and third years were collected, high-throughput sequencing technology was used to analyze bacterial microbiome compositions, and the contents of bioactive compounds were determined, including polydatin, resveratrol, emodin and physcion. The relationship between the root-associated bacteria and the bioactive components was explored through Pearon correlation analysis.【Result】Bioactive ingredients were distinct across different cultivation years（P < 0.05）. Pseudomonas and Sphingomonas were the most abundant genus of bulk soil and rhizosphere microbiome, while Pseudomonas, Chloroplast and Actinoplanes were the most dominant in the root endophyte. The abundance of Sphingomonas in the rhizosphere soil was decreasing year by year, the abundance of Pseudomonas in the root was decreasing year by year, while the abundance of Chloroplast in root was increasing year by year. The alpha diversity significantly varied along with the soil and root sample with different growth years, the abundance and diversity of bacteria in the bulk soil and rhizosphere were higher than that in root（P < 0.05）. The microbiome composition among the bulk soil, rhizosphere soil and roots extremely significantly differed（P < 0.001）, it also significantly differed across 1-year, 2-year, and 3 -year ones（P < 0.05）. The microbiome composition among the bulk soil and rhizosphere soil was significantly affected by cultivation years（P < 0.05）, while the root endosphere microbiome was not significantly affected by the growth years（P > 0.05）. The content of polydatin was significantly positively correlated with the relative abundance of Microvirga and Gaiella in rhizosphere, significantly positively correlated with the relative abundance of Pseudomonas in the root, and significantly negatively correlated with the relative abundance of Actinoplanes and Nocardioides in the root. The content of resveratrol was significantly negatively correlated with the relative abundance of Actinoplanes and Nocardioides in the root. The content of emodin was significantly positively correlated with the relative abundance of Arthrobacter in the rhizosphere, significantly positively correlated with the relative abundance of Mycobacterium in root, and significantly negatively correlated with the relative abundance of Pseudomonas in root. The content of physcion was significantly positively correlated with the relative abundance of Arthrobacter in the rhizosphere, significantly positively correlated with the relative abundance of Mycobacterium in the root, as well as significantly negatively correlated with the relative abundance of Actinoplanes in the root. 【Conclusion】This study provides insights into the interaction networks between P. cuspidatum root-associated bacteria and bioactive compounds, giving us a new opportunity to manipulate the production of bioactive compounds in future.

Key words: Polygonum cuspidatum, high-throughput sequencing, root-associated bacteria, community composition, active ingredient