Fingerprinting metabolomics in tropical mistletoes: A case study with facultative aluminum-accumulating species

Abstract

Aluminum (Al) toxicity is a hot topic due to the high sensitivity of cultivated plants. Despite the large investment in the last century in understanding the mechanisms used by sensitive and Al-excluding species to avoid Al uptake from soil, little attention has been devoted to understanding the mechanisms used by native Al-accumulating species to deal with Al-toxicity. Passovia ovata (Pohl ex DC.) Kuijt and Struthanthus polyanthus Mart. are mistletoes with a facultative Al-accumulating behavior. In the Brazilian Cerrado they are commonly found infecting Al-accumulating (Miconia albicans (Sw.) Steud.) and non-accumulating (Byrsonima verbascifolia (L.) DC.) species. Taking into account the importance of organic complexes in the detoxification of the highly toxic Al3+ ions, it is to be expected that mistletoes differ in their metabolomic profile when feeding on species differing in Al accumulation. Here we tested this hypothesis using an untargeted LC–MS approach to investigate the influence of Al on the metabolome of P. ovata and S. polyanthus infecting M. albicans and B. verbascifolia under field conditions. We observed differences in the metabolic profiles between mistletoes growing on Al-accumulating and Al-excluding hosts, and also observed a positive correlation between Al leaf-accumulation and the metabolic profile. Using the OPLS-DA, we identified quinic acid (phenolic compound) as a metabolic biomarker distinguishing mistletoes grown under high and low Al availability.