Integrative physiological and metabolic traits reveal the mechanisms of chamomile flowers in response to nicotine stress

Abstract

Background: Chamomile (Matricaria recutita L.) is an important economic crop after tobacco (Nicotiana tabacum L.) cultivation. The nicotine released into the soil during tobacco cultivation has an impact on various aspects of chamomile growth, including plant height, flowering period, flower yield, and flower quality. We aimed to examine the effects of physiological and metabolic response of chamomile under different concentrations of nicotine stress. Results: The study revealed that chamomile growth was positively influenced by nicotine concentrations of 1.0 μg/g (N-1) and 10.0 μg/g (N-10). However, higher nicotine concentrations of 100.0 μg/g (N-100) and 500.0 μg/g (N-500) were found to induce stress as the highest levels of antioxidant enzyme activities and malondialdehyde (MDA) levels were observed under this treatment. In addition, it was observed that nicotine was transported from the roots to other organs during the entire growth period of chamomile and the nicotine levels reached saturation under N-100 treatment. A total of 1096 metabolites were detected by ultra-high-performance liquid chromatography-coupled tandem mass spectrometry (UHPLC–MS/MS) analysis, and 48 differentially expressed metabolites (DEMs) were identified among the groups via widely targeted metabolomics studies. The response of chamomile flowers to nicotine stress is associated with the presence of flavonoids, phenolic acids, organic acids, and other substances. Metabolic regulation under nicotine stress primarily involves processes, such as aminoacyl-tRNA biosynthesis, ABC (ATP-binding cassette) transporter activity, glyoxylate and dicarboxylate metabolism and pyrimidine metabolism. Conclusions: This report presents the first findings on how nicotine affects the metabolism of chamomile. It also provides a comprehensive understanding of how crops can resist nicotine stress from a metabolic perspective. Graphical Abstract: [Figure not available: see fulltext.].