Molecular mechanisms for pH-mediated amelioration of aluminum-toxicity revealed by conjoint analysis of transcriptome and metabolome in Citrus sinensis roots

• Published in: Chemosphere (Oxford) 2022-07, Vol.299, p.134335-134335, Article 134335
• Main Authors: Wu, Bi-Sha, Zhang, Jiang, Huang, Wei-Lin, Yang, Lin-Tong, Huang, Zeng-Rong, Guo, Jiuxin, Wu, Jincheng, Chen, Li-Song
• Format: Article
• Language: English
• Subjects: Aluminum - metabolism; Aluminum-toxicity; Citrus; Citrus sinensis; Citrus sinensis - metabolism; Hydrogen-Ion Concentration; Metabolic adaptations; Metabolome; pH-aluminum interactions; Plant Roots - metabolism; Roots; Transcriptome
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.134335

Little is known about the effects of pH-aluminum (Al) interactions on gene expression and/or metabolite profiles in plants. Eleven-week-old seedlings of Citrus sinensis were fertilized with nutrient solution at an Al level of 0 or 1 mM and a pH of 3.0 or 4.0 for 18 weeks. Increased pH mitigated Al-toxicity-induced accumulation of callose, an Al-sensitive marker. In this study, we identified more differentially expressed genes and differentially abundant metabolites in pH 4.0 + 1 mM Al-treated roots (P4AR) vs pH 4.0 + 0 mM Al-treated roots (P4R) than in pH 3.0 + 1 mM Al-treated roots (P3AR) vs pH 3.0 + 0 mM Al-treated roots (P3R), suggesting that increased pH enhanced root metabolic adaptations to Al-toxicity. Further analysis indicated that increased pH-mediated mitigation of root Al-toxicity might be related to several factors, including: enhanced capacity to maintain the homeostasis of phosphate and energy and the balance between generation and scavenging of reactive oxygen species and aldehydes; and elevated accumulation of secondary metabolites such as polyphenol, proanthocyanidins and phenolamides and adaptations of cell wall and plasma membrane to Al-toxicity. [Display omitted] •High pH reduced Al-induced increases of root Al and callose and decrease of growth.•High pH elevated root cell wall and plasma membrane the adaptations to Al-toxicity.•High pH enhanced root capacity to maintain the homeostasis of phosphate and energy.•High pH improved SM biosynthesis and reduced oxidative damage in Al-treated roots.