Metabolomic Characterization and Bioactivity Assessment of Major Saponin Classes in Genetically Diverse Quinoa 

Quinoa (Chenopodium quinoa Willd.) seeds contain diverse triterpenoid saponins with potential antifungal, insecticidal, antimicrobial and surfactant properties. Most studies distinguish quinoa genotypes mainly by total saponin content, whereas the relationship between individual saponin classes and biological activity remains insufficiently understood. 

This project will investigate the quantity, chemical diversity and bioactivity of the two major quinoa saponin classes: hederagenin-derived and oleanolic-acid-derived saponins. A panel of genetically diverse quinoa genotypes with contrasting high and low total saponin contents will be selected and grown under standardized conditions. 

Metabolomic analyses will be conducted at the Agricultural University of Athens in the laboratory of Prof. Konstantinos Aliferis. Untargeted LC-HRMS profiling will first be used to characterize the overall saponin composition and identify genotype-specific metabolic patterns. This will be followed by targeted or semi-targeted quantification of major hederagenin- and oleanolic-acid-derived saponins. Where appropriate, hydrolysis-based sapogenin analysis will complement intact-saponin profiling. 

Chemically characterized crude extracts and saponin-enriched fractions will subsequently be tested in selected bioassays, with an initial focus on antifungal activity against relevant plant pathogens such as Botrytis cynerea, Colletotrichum acutatum Fusarium oxysporum and Rhizoctonia solani. Phytotoxicity assays will be included to identify active but crop-compatible concentrations on leaves of important plant species such tomato, corn, lettuce and olive tree. Additionally, an ecotoxicological assessment can be conducted using the standard test organisms Lemna minor and Lemna gibba. 

The project will determine whether bioactivity is primarily associated with total saponin concentration, the ratio between the two major saponin classes, or specific individual compounds. The results will identify promising quinoa genotypes and saponin chemotypes for future development of botanical pesticides, biostimulants or natural formulation adjuvants. The study will also provide a basis for larger-scale genetic analyses, including association mapping and breeding for valuable saponin profiles. 

General learning outcomes

• Explain the role of plant secondary metabolites, particularly saponins, in plant defense and their potential applications as biopesticides and biostimulants. 

• Apply metabolomics approaches to characterize and compare saponin profiles in quinoa genotypes with contrasting saponin contents. 

• Interpret metabolomic and bioactivity datasets to identify relationships between saponin composition and biological activity against plant pathogens. 

• Evaluate the potential of naturally occurring saponins for sustainable crop protection and discuss their advantages and limitations compared with conventional pesticides. 

• Collaborate in an international research environment by contributing to experimental design, data analysis, scientific communication, and the development of future research directions in plant metabolomics and crop improvement