Biochemistry

Carotenoids in plants play several key functions such as acting as light-harvesters, antioxidants (Lado et al., 2016) or being precursors of strigolactones, abscisic acid, volatiles and other signaling compounds (Arbona et al., 2013). Although those functions are well-known in light-exposed tissues, information in belowground organs is limited because of reduced abundance of these pigments. In order to better understand the role of carotenoids in roots, we developed a methodology to increase the abundance of these pigments in underground tissues. We took advantage of the fact that citrus roots exposed to light develop pigmentation in order to increase the carotenoid content. Therefore, here we describe a simple method to increase carotenoids in citrus roots.

This is a protocol for precise measurement of chlorophyll a and total carotenoid concentrations in cyanobacteria cells. Cellular chlorophyll concentration is one of the central physiological parameters, routinely followed in many research areas ranging from stress physiology to biotechnology. Carotenoids concentration is often related to cellular stress level; combined pigments assessment provides useful insight into cellular physiological state. The current protocol was established to minimize time and equipment requirements for the routine pigments analysis. It is important to note that this protocol is suitable only for cyanobacteria containing chlorophyll a, and is not designed for species containing other chlorophyll molecules.

Carotenoids are ubiquitous pigments that play key roles in photosynthesis and also accumulate to high levels in fruit and flowers. Specific carotenoids play essential roles in human health as these compounds are precursors for Vitamin A; other specific carotenoids are important sources of macular pigments and all carotenoids are important anti-oxidants. Accurate determination of the composition and concentration of this complex set of natural products is therefore important in many different scientific areas. One of the richest sources of these compounds is the fruit of Capsicum; these red, yellow and orange fruit accumulate multiple carotenes and xanthophylls. This report describes the detailed method for the extraction and quantification of specific carotenes and xanthophylls.