Trichoderma crassum WMM-1-7 reshapes the rhizosphere metabolome of Pseudostellaria heterophylla with benefits

Pseudostellaria heterophylla (Miq.) Pax ex Pax et Hoffm. is a medicinally and economically critical plant cultivated for its tuberous roots, with a documented history in traditional medicine spanning three millennia. Under the escalating pressures of global climate change (e.g., drought and soil salinization), ensuring stable and high-yield production of P. heterophylla is imperative for market sustainability. The beneficial fungus T. crassum has demonstrated potential in enhancing crop abiotic stress resistance through multiple biological processes. Critically, Trichoderma-mediated rhizosphere metabolite reprogramming may underpin its role in protecting P. heterophylla against environmental stresses, thereby ensuring yield stability. Elucidating the metabolic shifts driven by T. crassum is thus essential for harnessing its full agronomic potential. In this study, we employed UHPLC‒MS/MS to analyze the metabolic profiles of Pseudostellaria heterophylla under separate and coculture conditions with different concentrations of T. crassum. The results indicated that 521, 376, and 594 DAMs were identified in each treatment group and the control group, respectively. KEGG enrichment analysis revealed 11 pathways associated with abiotic stress, and DAMs such as cucurbitacin E and secologanin were significantly enriched in these pathways. Additionally, 5 pathways related to component synthesis were identified. Key metabolites such as 5,6-epoxy-8,11,14-eicosatrienoic acid and D-glucose were enriched in these pathways. Fourteen pathways were enriched with metabolites (e.g., sucrose, trehalose, and protocatechuic acid) critical for plant growth. We hypothesize that the differentially abundant metabolites within these pathways may contribute to enhancing the stress resistance of P. heterophylla through putative mechanisms, such as increasing the activity of resistance enzymes, maintaining cellular osmotic balance, promoting hormone synthesis, enhancing cell wall synthesis, and facilitating root cell division and elongation. This study revealed that T. crassum remodels the rhizosphere metabolites of heterophylla, laying the groundwork for its agronomic application to bolster crop hardiness.