Tithonia diversifolia is an invasive weed commonly found in tropical ecosystems. In this work, we investigate the influence of different abiotic environmental factors on the plant’s metabolite profile by multivariate statistical analyses of spectral data deduced by UHPLC-DAD-ESI-HRMS and NMR methods. Different plant part samples of T. diversifolia which included leaves, stems, roots and inflorescences were collected from two Brazilian states throughout a 24-month period, along with the corresponding monthly environmental data. A metabolomic approach employing concatenated LC-MS and NMR data was utilised for the first time to study the relationships between environment and plant metabolism. A seasonal pattern was observed for the occurrence of metabolites that included sugars, sesquiterpenes lactones and phenolics in the leaf and stem parts, which can be correlated to the amount of rainfall and changes in temperature. The distribution of the metabolites in the inflorescence and root parts were mainly affected by variation of some soil nutrients such as Ca, Mg, P, K and Cu. We highlight the environment-metabolism relationship for T. diversifolia and the combined analytical approach to obtain reliable data that contributed to a holistic understanding of the influence of abiotic environmental factors on the production of metabolites in various plant parts.

Sesquiterpene lactones (STLs) constitute a large group of secondary metabolites that are widely distributed in several angiosperm plant families and a few bryophytes, including liverworts. These metabolites are particularly diversified in the family Asteraceae, in which more than 5,000 compounds have been reported so far. In addition to their pharmacological importance and potential therapeutic applications, most STLs display a wide range of protective activities in plants, including acting as anti-herbivory and antimicrobial substances or inhibiting growth of competing plants. These activities are mainly related to their characteristic α,β-unsaturated structural elements, which can participate in Michael-type additions with biological nucleophiles that contain sulfhydryl groups. Supporting the protective roles of STLs, they are mainly located in glandular trichomes of aerial parts because the highly nonspecific toxicity of such compounds necessitates compartmentalization to prevent autotoxicity. However, STLs have also been reported in other aerial and underground organs, where they are assumed to exhibit other biological activities. Recent studies have suggested that these metabolites not only display protective activities due to toxicity but also play key physiological roles in mediating rhizosphere communication among plants, soil microorganisms and plant parasites. STLs have been directly implicated in plant phototropism, resulting in differential growth of a plant organ due to auxin inhibition when accumulated in response to a light stimulus. This review therefore not only highlights the protective roles of STLs in producing plants but also explores the physiological roles of these metabolites, thus providing insights for new research approaches for understanding the roles of STLs in plants and their potential future applications.