Soil contamination by indium, an emerging contaminant from electronics, has a negative impact on crop growth. Inhibition of root growth serves as a valuable biomarker for predicting indium phytotoxicity. Therefore, elucidating the molecular mechanisms underlying indium-induced root damage is essential for developing strategies to mitigate its harmful effects. Our transcriptomic findings revealed that indium affects the expression of numerous genes related to cell wall composition and metabolism in wheat roots. Morphological and compositional analysis revealed that indium induced a 2.9-fold thickening and a 17.5 % increase in the content of cell walls in wheat roots. Untargeted metabolomics indicated a substantial upregulation of the phenylpropanoid biosynthesis pathway. As the major end product of phenylpropanoid metabolism, lignin significantly accumulated in root cell walls after indium exposure. Together with increased lignin precursors, enhanced activity of lignin biosynthesis-related enzymes was observed. Moreover, analysis of the monomeric content and composition of lignin revealed a significant enrichment of -hydroxyphenyl (H) and syringyl (S) units in root cell walls under indium stress. The present study contributes to the existing knowledge of indium toxicity. It provides valuable insights for developing sustainable solutions to address the challenges posed by electronic waste and indium contamination on agroecosystems.

中文翻译：

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综合转录组学和代谢组学分析揭示了铟诱导抑制小麦植物根伸长的潜在机制

铟（一种来自电子产品的新兴污染物）对土壤的污染会对农作物生长产生负面影响。根生长的抑制是预测铟植物毒性的一个有价值的生物标志物。因此，阐明铟引起的根部损伤的分子机制对于制定减轻其有害影响的策略至关重要。我们的转录组学研究结果表明，铟影响小麦根中与细胞壁组成和代谢相关的许多基因的表达。形态和成分分析表明，铟使小麦根部细胞壁增厚 2.9 倍，含量增加 17.5%。非靶向代谢组学表明苯丙素生物合成途径显着上调。作为苯丙素代谢的主要终产物，木质素在铟暴露后显着积累在根细胞壁中。随着木质素前体的增加，木质素生物合成相关酶的活性增强。此外，对木质素单体含量和组成的分析表明，在铟胁迫下，根细胞壁中的β-羟基苯基（H）和紫丁香基（S）单元显着富集。本研究有助于加深对铟毒性的现有认识。它为开发可持续解决方案提供了宝贵的见解，以应对电子废物和铟污染对农业生态系统带来的挑战。