Genome Designing for Nutritional Quality in Amaranthus

Known for its high nutritional value and ability to thrive in the most adverse conditions, amaranth grain is considered a superfood by many. Amaranth is gluten-free and rich in protein, especially lysine, an essential amino acid very scarce in other plants. The antioxidant properties of amaranth may improve the nutritional status and health of consumers. In fact, as an antioxidant, anti-inflammatory, and anticancer agent, amaranth has been pharmacologically reported to be highly effective against chronic inflammation. Other benefits of amaranth include lowering cholesterol and preventing cardiovascular disease. Even amaranth antinutrients, such as phenolic compounds, have antioxidant properties. Amaranth can be used for the biofortification of staple food by simply adding amaranth compounds to flour or bakery products. A more complex approach involves creating transgenic plants with higher nutritional profiles. Amaranth biofortification may also increase yield and resistance to multiple diseases. Despite these unique characteristics, amaranth is considered an underutilized grain, with greater potential to overcome hunger and diseases. One of the limitations of amaranth cultivation is the lack of high-yielding varieties. Therefore, we provide in this chapter a broad overview of amaranth grain cultivation and the current state of the art of genetic breeding of this crop. We highlight plant breeding using molecular markers and genetic diversity assessment. In addition, we describe the development of transgenic plants that have been enhanced by amaranth genes as well as new and promising gene editing techniques for amaranth, such as CRISPR and nanotechnology. Furthermore, we highlight the main germplasm and genomic databases for amaranth, as well as bioinformatic tools for assessing and analyzing the data. Altogether, this information may aid the rational design for nutritional quality and yields in Amaranthus and other plants, by using amaranth as a role model for nutritional improvement design.