Fabaceae (legumes) are one of the most important families of crop plants in the world, with a high economic relevance for human and livestock consumption. Legumes play an important role in the balance of animal and plant-based protein intake in healthier and more sustainable diets. Moreover, the high resilience of these plants to different edaphoclimatic conditions, allied with their capacity for biological nitrogen fixation and other environmental benefits, are key for their use in crop rotations towards more sustainable agricultural systems.

There is a large diversity of species and cultivars within this plant family and they each have different traits that adapt to different soil and climate conditions, allowing them to be cultivated in various areas across the globe. For that reason, plant response to abiotic and biotic stress conditions will vary among different Fabaceae species and cultivars, and in different agroclimatic regions.

Secondary metabolites play an important role in the plants’ defense system, providing protection against biotic and abiotic stresses such as drought, salinity, UV-radiation, extreme temperatures, herbivore and pathogen attacks, and soil characteristics. Chemically, secondary metabolites are distributed in four main classes: phenolics, terpenes, sulfur-containing, and nitrogen-containing metabolites. Around 200,000 compounds have been characterized in the Plantae kingdom. The profile of secondary metabolites in plants has been used to characterize metabolic pathways associated with stress conditions, phylogeny, and genetic variability, among others, to respond to various needs of the agricultural, food, and pharmaceutical sectors. The increasing improvements in cutting-edge and high-resolution analytical technologies, such as mass spectrometry analysis, have been giving a new impulse to metabolomic studies. The aim of this Research Topic is to improve our understanding of the response mechanisms of legumes to biotic and abiotic stress conditions through the characterization of the secondary metabolites profile.

In this Research Topic, we invite submissions of manuscripts focusing on metabolomic characterization of plants from the Fabaceae family related to biotic and abiotic stress. We welcome all article types, particularly original research papers and reviews, published by Frontiers in Plant Science that contribute, but are not limited to, the following topics:
• Metabolomic pathways and secondary metabolites profile in legumes as a response to biotic and abiotic stresses.
• Physiological and biochemical responses of plants exposed to biotic and abiotic stresses.
• Agronomic practices for mitigation of legume abiotic and biotic stresses and secondary metabolite pathways and profiles.
• New advances on the metabolomic characterization of Fabaceae plants.
• Integration of metabolomic studies with other omics techniques.