Metabolomic differences between invasive alien plants from native and invaded habitats

Abstract

Globalization facilitated the spread of invasive alien species (IAS), undermining the stability of the world’s ecosystems. We investigated the metabolomic profiles of three IAS species: Chromolaena odorata (Asteraceae) Datura stramonium (Solanaceae), and Xanthium strumarium (Asteraceae), comparing metabolites of individual plants in their native habitats (USA), to their invasive counterparts growing in and around Kruger National Park (South Africa, ZA). Metabolomic samples were collected using RApid Metabolome Extraction and Storage (RAMES) technology, which immobilizes phytochemicals on glass fiber disks, reducing compound degradation, allowing long-term, storage and simplifying biochemical analysis. Metabolomic differences were analyzed using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) of samples eluted from RAMES disks. Partial Least Squares-Discriminant Analysis (PLS-DA) of metabolomes of individual plants allowed statistical separation of species, native and invasive populations of each species, and some populations on the same continent. Invasive populations of all species were more phytochemically diverse than their native counterparts, and their metabolomic profiles were statistically distinguishable from their native relatives. These data may elucidate the mechanisms of successful invasion and rapid adaptive evolution of IAS. Moreover, RAMES technology combined with PLS-DA statistical analysis may allow taxonomic identification of species and, possibly, populations within each species.

Metabolomics, a Powerful Tool for Understanding Plant Abiotic Stress

“…The PLS-DA is an extension of PLS applied when the treatment variable is categorical instead of continuous. PLS-DA has been used to observe metabolic differences between invasive alien plants in native and invaded habitats, enabling statistical separation of the species under study [128]. In another research, PLS-DA was used for biomarker recognition of natural groups of fermented aqueous extracts of Viscum album L. [129].…”

Epigenetics and the success of invasive plants

“…In fact, metabolomic analyses have found some invasive species to harbour more total secondary metabolites related to generalist herbivores, such as flavonoids or glucosinolates, in their introduced range than in their native range (e.g. [59,81,[91][92][93][94]). To add even more complexity, plant defences can involve both resistance and tolerance mechanisms, where resistance generally reduces damage to plants [95], but tolerance mitigates the fitness impact of the damage, for example, through rapid re-growth [96].…”

“…An important additional tool in this context is metabolomic approaches that quantify plant secondary chemistry and provide a better understanding of the translation of genomic variation into plant defences and success in novel environments [59]. With appropriate experimental designs, metabolomic analyses can reveal how plant secondary chemistry is induced by abiotic and biotic stresses and thus provide a functional readout of genome-level processes complementary to transcriptomic studies.…”

“…[54][55][56]). Specific to the context of biological invasions, changes in gene expression can translate into variation in inducible defences and secondary metabolism, which combines into complex phenotypes that can be finely tuned and provide a diverse array of appropriate responses to environmental challenges in plants [57][58][59] and animals [60].…”

“…Researchers attempting to explain the huge success of these species often argue for the importance of phenotypic plasticity or 'general-purpose genotype' [8,[71][72][73], which could be mediated by epigenetic effects that translate into gene expression and changes in plant chemistry and other phenotypes [31,58,[74][75][76]. Many of the hypotheses that attempt to explain variation in invasion success involve genetic or plastic response to novel biotic interactions, often associated with changes in secondary metabolites [59,[77][78][79][80][81].…”