Soil pseudotargeted metabolomics reveals that planting years of masson pine (Pinus massoniana) affect soil metabolite profiles and metabolic pathways.

Aims: Soil metabolites have a great influence on regulating the growth and development of plants and microbes in forest ecosystems. This study aims to reveal the characteristic metabolite profiles and their enriched metabolic pathways in the rhizosphere soil of Masson pine plantations at three different ages. Method: The rhizosphere soil of Masson pine from 10, 31, and 52 years plantation was collected. The metabolites were analyzed using a soil pseudotargeted metabolomics approach and then the relationships between soil metabolites and chemical properties, enzyme activities were established. Results: A total of 172 rhizosphere soil metabolites in 26 classes were identified. There was a decreasing trend in the total concentration of rhizosphere soil metabolites with increasing stand age. Seventy-two characteristic metabolites were screened, mainly saccharides, fatty acids, amino acids, phenolic acids, polyols and terpenoids. Among them, benzoic acid and galactonic acid contributed the most to the young forest, and stearic acid had the greatest influence on the near-mature forest plantation. Erythritol had great effects on the mature forest plantation. Seven metabolic pathways changed with increasing stand age. Correlation analysis showed that available potassium (AK) and soil alkaline protease (S-ALPT) were significantly positively correlated with phenolic acids, polyhydroxy carboxylic acids, etc. Conclusion: The rhizosphere soil of Masson pine had different metabolite profiles at different developmental stages, and the soil nutrient pools were effectively improved. These results provide a reference for plantation management in Masson pine and a deeper understanding of forest metabolic characteristics. [ABSTRACT FROM AUTHOR]