The key metabolic pathway of roots and leaves responses in Arachis hypogaea under Al toxicity stress

Aluminum (Al) toxicity inhibits plant growth and alters gene expression and metabolite profiles. However, the molecular mechanisms underlying the effects of Al toxicity on peanut plants remain unclear. Transcriptome and metabolome analyses were conducted to investigate the responses of peanut leaves and roots to Al toxicity.

Al toxicity significantly inhibited peanut growth, disrupted antioxidant enzyme systems in roots and leaves, and impaired nutrient absorption. Under Al toxicity stress, the content of indole-3-acetic acid-aspartate (IAA-Asp) decreased by 23.94% in leaves but increased by 12.91% in roots. Methyl jasmonate (MeJA) levels in leaves increased dramatically by 2642.86%. Methyl salicylate (MeSA) content in leaves and roots increased significantly by 140.00% and 472.22%, respectively. Conversely, isopentenyl adenosine (IPA) content decreased by 78.95% in leaves and 20.66% in roots. Transcriptome analysis identified 5831 differentially expressed genes (DEGs) in leaves and 6405 DEGs in roots, whereas metabolomics analysis revealed 210 differentially accumulated metabolites (DAMs) in leaves and 240 DAMs in roots. Under Al toxicity stress, both leaves and roots were significantly enriched in the "linoleic acid metabolism" pathway. Genes such as lipoxygenase LOX1-5 and LOX2S were differentially expressed, and metabolites, including linoleic acid and its oxidized derivatives, were differentially accumulated, mitigating oxidative stress.

This study elaborates on the potential complex physiological and molecular mechanisms of peanuts under aluminum toxicity stress, and highlights the importance of linoleic acid metabolism in coping with aluminum toxicity. These findings enhance our understanding of the impact of aluminum toxicity on peanut development and the response of key metabolic pathways, providing potential molecular targets for genetic engineering to improve crop resistance to aluminum stress.