College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
Environ Pollut. 2022 Sep 15;309:119709. doi: 10.1016/j.envpol.2022.119709. Epub 2022 Jul 13.
Understanding the metabolic defense and compensation to maintain homeostasis is crucial for assessing the potential health risk of organic pollutants in crops. Currently, limited understanding is available regarding the targeted metabolic pathways and response mechanism under contaminant stress. This study showed that ciprofloxacin (CIP) at the environmental concentrations (1, 5, 25, 50 mg/L) did not significantly inhibit growth or cause severe oxidative damage to rice (Oryza sativa L.). Instead, the increment in CIP concentration induced a series of sequential metabolic disorders, which were characterized predominantly by primary and secondary metabolic disturbances, including phenylpropanoid biosynthesis, the carbohydrate, lipid and amino acid metabolism. After CIP in vivo exceeded a certain threshold level (>0.29 mg/g dry weight), β-glucosidases (BGLUs) mediated the transition from the activation of the genes related to phenylpropanoid biosynthesis to the inhibition of the genes related to carbohydrate metabolism in rice. In particular, starch and sucrose metabolism showed the most profound perturbation stressed by environmental concentrations of CIP (5 mg/L) and other tested organic pollutants (10 μg/L of tricyclazole, thiamethoxam, polybrominated diphenyl ethers, and polychlorinated biphenyls). Besides, the key genes encoding endoglucanase and BGLU were significantly downregulated (|logFC| > 3.0) under 100 μg/L of other tested organic pollutants, supporting the transition from the activation of secondary defense metabolism to the disruption of primary energy metabolism. Thus, in addition to bioaccumulation, changes in BGLU activity and starch and sucrose metabolism can reflect the potential adverse effects of pollutants on rice. This study explained the stepwise metabolic and transcriptional responses of rice to organic pollutants, which provided a new reference for the comprehensive evaluation of their environmental risks.
了解维持内稳态的代谢防御和补偿对于评估作物中有机污染物的潜在健康风险至关重要。目前，对于污染物胁迫下的靶向代谢途径和响应机制，我们的了解有限。本研究表明，环丙沙星（CIP）在环境浓度（1、5、25、50mg/L）下不会显著抑制水稻（Oryza sativa L.）的生长或造成严重的氧化损伤。相反，CIP 浓度的增加诱导了一系列连续的代谢紊乱，主要表现为初级和次级代谢紊乱，包括苯丙素生物合成、碳水化合物、脂质和氨基酸代谢。当 CIP 在体内超过一定阈值水平（>0.29mg/g 干重）后，β-葡萄糖苷酶（BGLUs）介导了从与苯丙素生物合成相关基因的激活到与碳水化合物代谢相关基因的抑制的转变。特别是在环境浓度的 CIP（5mg/L）和其他测试的有机污染物（10μg/L 的三唑酮、噻虫嗪、多溴二苯醚和多氯联苯）胁迫下，淀粉和蔗糖代谢表现出最显著的扰动。此外，在 100μg/L 的其他测试有机污染物下，编码内切葡聚糖酶和 BGLU 的关键基因显著下调（|logFC|>3.0），支持从次级防御代谢的激活到初级能量代谢的破坏的转变。因此，除了生物积累之外，BGLU 活性和淀粉和蔗糖代谢的变化可以反映污染物对水稻的潜在不利影响。本研究解释了水稻对有机污染物的逐步代谢和转录响应，为全面评估其环境风险提供了新的参考。
