The College of Landscape Architecture and Arts, Northwest A&F University, Yangling 712100, China.
The College of Landscape Architecture and Arts, Northwest A&F University, Yangling 712100, China.
Sci Total Environ. 2024 Feb 1;910:168615. doi: 10.1016/j.scitotenv.2023.168615. Epub 2023 Nov 19.
Lead (Pb) soil contamination has caused serious ecological and environmental issues. Hydrangea macrophylla is a potential Pb-contaminated soil remediation plant, however, their Pb stress defense mechanism is largely unknown. Here, the physiology, transcriptomic and metabolome of two H. macrophylla cultivars (ML, Pb-sensitive cultivar; JC, Pb-resistant cultivar) under Pb stress were investigated. The results demonstrated that JC performed superiorly, with activities of the antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were 1.25, 2.84, and 1.67 times higher than those of ML after Pb treatment, respectively, and the amount of soluble sugar in JC increased by 231.34 % compared with that in ML. The electrical conductivity (EC) value of the root exudates of JC was 43.71 % lower than that of ML under Pb stress. The non-targeted metabolomics analysis revealed 193 metabolites grouped into nine categories. Pb stress-induced differential expression of the 37 metabolites, among which the major metabolites up-regulated in ML were organic acids, while in JC, these were carbohydrates, fatty acids, organic acids and lipids. The transcriptomic analysis revealed that Pb exposure induced 1075 and 1314 differentially expressed genes (DEGs) in JC and ML, respectively. According to the functional annotation results, hub genes were primarily enriched in carbohydrate metabolism, root growth, and plant resistance to external stresses. A conjoint analysis of the two omics indicated that the cutin, suberine and wax biosynthesis pathway in JC played an essential role in Pb detoxification. These findings clarify the resistance mechanism of H. macrophylla to Pb stress and open up a new avenue for breeding H. macrophylla Pb-resistant cultivars.
铅（Pb）土壤污染已造成严重的生态和环境问题。绣球花是一种有潜力的 Pb 污染土壤修复植物，但它们的 Pb 胁迫防御机制在很大程度上尚不清楚。在这里，研究了两种绣球花品种（ML，Pb 敏感品种；JC，Pb 耐受品种）在 Pb 胁迫下的生理学、转录组和代谢组。结果表明，JC 表现出色，Pb 处理后，超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性分别比 ML 高 1.25、2.84 和 1.67 倍，JC 中的可溶性糖含量比 ML 增加了 231.34%。在 Pb 胁迫下，JC 的根分泌物电导率（EC）值比 ML 低 43.71%。非靶向代谢组学分析揭示了 193 种代谢物分为九类。37 种代谢物在 Pb 胁迫下差异表达，其中 ML 上调的主要代谢物为有机酸，而 JC 中则为碳水化合物、脂肪酸、有机酸和脂质。转录组分析表明，Pb 暴露分别诱导 JC 和 ML 中 1075 和 1314 个差异表达基因（DEGs）。根据功能注释结果，枢纽基因主要富集在碳水化合物代谢、根系生长和植物对外界压力的抗性。两个组学的联合分析表明，JC 中的角质、栓质和蜡生物合成途径在 Pb 解毒中起着重要作用。这些发现阐明了绣球花对 Pb 胁迫的抗性机制，并为培育绣球花 Pb 耐受品种开辟了新途径。
