Visualizing the distributions and spatiotemporal changes of metabolites in wild and tissue cultured Polygonatum cyrtonema Hua by MALDI mass spectrometry imaging

The rhizome of Polygonatum cyrtonema Hua ( P. cyrtonema ) is a valuable medicinal and edible resource material. To explore functional metabolite spatial distribution and enhance utilization efficiency in P. cyrtonema , this study established a tissue culture system for rapid induction and proliferation of microrhizomes using mature seeds of P. cyrtonema , spatial metabolomics via MALDI-MSI analyzed metabolite distributions across wild rhizomes cross-sections, sprout/rhizome and microrhizomes longitudinal-sections. We mapped 93 metabolites (e.g., saccharides, organic/amino acid derivatives, alkaloids, esters, flavonoids). Saccharides accumulated primarily in rhizomes. Organic acid derivatives and alkaloids dominated sprouts and rhizomes. Amino acid derivatives localized mainly to sprouts and rhizome periderm. Small peptides were enriched in rhizome periderm and sprout surfaces, suggesting their potential role in rhizome growth and stress defense mechanisms of P. cyrtonema . Co-enrichment of amino acid derivatives and alkaloids in wild P. cyrtonema vascular bundles and shoot apex supports a putative long-distance transport function that may facilitate bud growth. Crucially, osmotic stress from high sucrose may contribute to elevated metabolite levels in microrhizomes, especially organic/amino acid derivatives and saccharides. These findings highlight the substantial application potential of microrhizomes for functional metabolite production. This study provides vital data for enhancing P. cyrtonema metabolite processing and industrial production. • Microrhizomes can be induced efficiently by using P. cyrtonema seeds. • Spatial metabolite heterogeneity exists between wild-type and micro-rhizomes. • Small peptide enrichment in P. cyrtonema periderm and sprouts points to putative functions in growth and stress defense. • Amino acid and alkaloids co-enriched in vasculature/shoot apex supports a putative long-distance transport function. • Osmotic stress from high sucrose may contribute to elevated metabolite levels in microrhizomes.