Leaf metabolic profile of a broad panel of vanilla to link metabolic traits with vanilla phenotypes

Natural vanilla is a unique spice of great commercial value obtained from the fruit of Vanilla planifolia (Orchidaceae), V. tahitensis, or V. pompona. Vanilla extracts are known to be composed of vanillin, usually the mayor constituent, present in a complex mixture comprised, amongst others, of vanillyl, phenolic, and anisylic compounds, at concentrations which vary with the plant species. This mixture of compounds making up the unique aroma is known as vanillat. Even though vanillin is one of the most widely used flavoring natural products throughout the world, research on the elucidation of the biosynthetic pathways leading to its production and to that of the related-compounds is still unknown. Recently, the dependency of photoassimilates produced in the leaf for the biosynthesis of vanillat has been hinted. This information is crucial for breeding regimes as it will allow selecting plants based on their metabolic phenotype to increase and/or improve the vanillin production in the pods. We propose to use a nuclear magnetic resonance platform coupled with statistical and multivariate data analyses to profile and compare leaves – organ known to accumulate vanillin putative precursors – of Vanilla sp. grown in Peruvian habitat against species cultivated at Tropical Research and Education Center (UoF). Emphasis will be displayed in the assessment of the phenolic compounds possibly implicated in the biosynthetic route of vanillin, namely Glucoside A and B, 4-hydroxybenzyl alcohol and its glucoside. Also, the presence of homocitric acid, an unusual organic acid in plants with no declared role in leaves, recently reported to be present in some Vanilla sp., will be assessed. The aim is to yield metabolic blueprints to be used in further more comprehensive studies, i.e., correlation-based network analysis (CNA) to link metabolites to the genome, information that would aid in the implementation of new breeding processes and genetic/metabolic engineering of natural vanilla.