Multi-dimensional analyses of physiology, biochemistry, cytology and transcriptomics reveal key pathways and hub genes in Platostoma palustre response to Cd stress

Cadmium (Cd) is a toxic heavy metal that readily enters the food chain from soil, threatening food security and human health. While plants have evolved intricate defense systems against heavy metal stress, the molecular mechanisms of Cd detoxification and tolerance in non-model medicinal plants remain unclear. Platostoma palustre , a valuable medicinal and edible plant in East and Southeast Asia that is rich in bioactive polysaccharides and flavonoids, has not been studied for its multi-dimensional responses to Cd stress. Herein, we integrated physiology, biochemistry, cytology, and transcriptomics (with WGCNA) to elucidate its Cd response mechanisms. Results showed Cd stress significantly inhibited the growth and development and induced oxidative stress in P. palustre , while the contents of protective metabolites (soluble protein, soluble sugar, flavonoids, and soluble pectin) increased. Roots accumulated far more Cd than leaves and stems. Transcriptomic analysis identified key pathways (isoquinoline alkaloid, phenylpropanoid, and polysaccharide biosynthesis) and hub genes (e.g., Mesona_chinensis0110990.1 (GMPP), Mesona_chinensis0024410.1 (YABBY), Mesona_chinensis0356980.1 (YWHAE)). Heterologous overexpression of GMPP enhanced Cd tolerance in yeast. This study provides novel insights into P. palustre ’s Cd stress response and potential genetic targets for improving stress resilience in this medicinal species. • P. palustre is an important medicinal and edible plant in China and Southeast Asian countries. • Cd stress significantly inhibits P. palustre plant growth and development. • Cd stress notably affects key quality components (polysaccharides, flavonoids) of P. palustre . • WGCNA reveals three biosynthesis pathways involved in P. palustre ’s Cd stress response. • GMPP plays a critical regulatory role in response to cadmium stress in P. palustre .