Healthy and unhealthy plants: The effect of stress on the metabolism of Brassicaceae

Brassicaceae plants are one of the most popular vegetables consumed all over the world and considered to be a good source of bioactive phytochemicals. Additionally, Brassica species and varieties are increasingly becoming a research model in plant science, as a consequence of the importance of their primary and secondary metabolites. Plant interaction with environmental stress factors including animals and insects herbivory, pathogens, metal ions, light, among others, is known to lead to the activation of various defense mechanisms resulting in a qualitative and/or quantitative change in plant metabolite production. Pre-harvest and/or post-harvest conditions are also known to affect this, since plants produce signaling molecules (e.g. salicylic acid, jasmonic acid, etc.) that cause a direct or indirect activation of metabolic pathways. That ultimately affects the production of phytochemicals, such as carbohydrates (sucrose and glucose), amino acids, phenolics (phenylpropanoids and flavonoids) and glucosinolates. These phytochemicals have diverse applications due to their antimicrobial, antioxidant and anti-carcinogenic properties, but on the other hand these compounds or their breakdown products can act as anti-nutritional factors in diet. In this review we report a wide range of the stress-induced metabolic responses in the Brassica plants commonly used for human consumption.