Integrated transcriptomics and metabolomics reveal key metabolic pathway responses in Iris tectorum under chromium stress

Chromium (Cr) induces molecular alterations, disrupts metabolites, and impedes plant growth, necessitating the elucidation of the molecular stress mechanism underlying Cr tolerance in plants to evaluate the enduring environmental effects of Cr stress. In this study, I. tectorum was employed as the experimental model to scrutinize Cr accumulation and transport, along with physiological alterations in antioxidants, metabolites, and functional genes in plants under Cr stress. The findings exhibited a significant reduction in plant biomass under Cr stress, accompanied by pronounced enhancements in Cr enrichment capacity and homeostatic oxidative stress ability. Metabolomic analysis revealed that Cr stress primarily affected nine metabolic pathways in I. tectorum, involving 25 differentially expressed metabolites (DEMs), predominantly comprising fatty acids, terpenoids, flavonoids, phenylpropanoids, and organic acids. In addition, the transcriptomic analysis identified a total of 19,136 differentially expressed genes (11994 up-regulated and 7142 down-regulated DEGs) across the three comparison groups. These DEGs were primarily associated with cell wall biosynthesis, oxidative stress response, signal transduction, and plant carbohydrate metabolism pathways. A comprehensive analysis unveiled the pivotal roles of the cell wall biosynthetic pathway and the oxidative stress system in I. tectorum for Cr detoxification. In conclusion, this study encompassed a comprehensive investigation utilizing diverse methodologies to unravel the molecular detoxification mechanism employed by I. tectorum, a wetland plant, in combating Cr stress.

铬（Chromium, Cr）可诱导分子改变、扰乱代谢物稳态并阻碍植物生长，因此亟需阐明植物耐铬胁迫的分子应激机制，以评估铬胁迫的长期环境影响。本研究以鸢尾（Iris tectorum）为实验模型，探究铬胁迫下植物的铬积累与转运过程，以及抗氧化系统、代谢物和功能基因的生理变化。研究结果显示，铬胁迫下植物生物量显著降低，同时铬富集能力与氧化应激稳态能力显著提升。代谢组学分析表明，铬胁迫主要影响鸢尾的9条代谢通路，涉及25种差异表达代谢物（differentially expressed metabolites, DEMs），主要包括脂肪酸、萜类、黄酮类、苯丙素类及有机酸。此外，转录组学分析在3个比对组中共鉴定出19136个差异表达基因（differentially expressed genes, DEGs），其中上调基因11994个、下调基因7142个。这些DEGs主要参与细胞壁生物合成、氧化应激响应、信号转导及植物碳水化合物代谢通路。综合分析揭示了细胞壁生物合成通路与氧化应激系统在鸢尾抵御铬毒害中的关键作用。综上，本研究通过多种方法开展综合探究，阐明了湿地植物鸢尾对抗铬胁迫的分子解毒机制。