Sex specificity of root exudates and their effects on rhizosphere microorganisms in a rare and endangered plants, Taxus cuspidata

Abstract

Dioecious plants exhibit sexual dimorphism not only in morphological structure, physiological metabolism, and resource acquisition but also in belowground microecosystems. In this study, high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS) were employed to detect sex-specific differences in root exudates of the typical dioecious plant Taxus cuspidata between adult and juvenile stages. High-throughput sequencing was used to analyze sex- and stage-specific differences in rhizosphere microbial communities. The results showed that in the adult stage, female plants enriched 2-mercaptoethanesulfonic acid and -keto-{gamma}-methylthiobutyric acid, while male plants secreted more terpenoids (e.g., -humulene) and purine metabolic intermediates (xanthine). In the juvenile stage, female plants exhibited higher expression of phosphoenolpyruvate and L-valine, whereas male plants enriched 5-methylcytosine and tricyclic sesquiterpenoid antibiotics. The diversity of rhizosphere microorganisms showed a sex-reversal pattern across different developmental stages. Correlation analysis revealed that in the adult stage, the abundance and diversity of bacteria (Proteobacteria) and fungi (Mortierellomycota) were higher in female than in male plants, which were enriched with Actinobacteria. In the juvenile stage, male plants exhibited greater diversity of both rhizosphere bacteria and fungi than female plants, with enrichment of stress-tolerant and decomposing microorganisms (e.g., Humicola). The findings reveal different resource allocation and environmental adaptation strategies in the belowground parts of dioecious plants, which are of great value for the conservation of rare and endangered plants.