From existing amino acids, twenty are directly involved in the formation of proteins. The others are known as non- proteinogenic amino acids (NPAA). The NPAA have different functions, including anti-herbivory activity, antimicrobial, protection from stress, cell signaling, nitrogen storage, as toxins against invertebrates and vertebrates and as allelochemicals. Plants are able to release these metabolites in the soil, which may influence the growth and development of neighboring plants, both positively and negatively. The objective of this review is to describe […]