A Plant Growth‐Promoting Fungus Cladosporium sphaerospermum Attenuates Cadmium Stress in Wheat via Gene Expression and Metabolite Production

ABSTRACT

Cadmium (Cd) contamination has threatened plant health and resulted in a notable reduction of crop yields. Cladosporium sphaerospermum is known as a plant growth‐promoting fungus that modulates plant development under abiotic conditions. However, the molecular mechanisms underlying C. sphaerospermum ‐mediated alleviation of Cd toxicity in wheat is unknown. By integrating physio‐biochemical, transcriptomic and metabolomic analysis, the beneficial roles of C. sphaerospermum in moderating Cd‐induced (100 μM CdCl ₂ ) toxicity in wheat seedlings ( Triticum aestivum L.) were studied here. C. sphaerospermum enhanced plant growth under Cd conditions by reducing MDA content and increasing antioxidant enzyme activities to re‐establish redox homeostasis. Expression of wheat genes in MAPK pathways, plant hormone signal transduction, glutathione metabolism and cysteine metabolism pathways were notably differentially regulated by C. sphaerospermum under Cd conditions. The metabolites involved in oxidative phosphorylation, amino acid metabolism and tRNA biosynthesis were significantly modulated by C. sphaerospermum under Cd conditions. Integrated transcriptome and metabolome analysis indicated that the genes and metabolites in glutathione metabolism and cysteine metabolism pathways were crucial for C. sphaerospermum ‐mediated mitigation of Cd toxicity in wheat. The findings provide new insights into the molecular mechanisms of fungus‐regulated wheat tolerance to Cd toxicity. C. sphaerospermum , as a promising and eco‐friendly plant growth‐promoting fungus, is suggested to be applied in Cd contaminated soil for food safety production.