A Comparative Genomic Study of the C3 Sugar Beet and the C4 Edible Grain Amaranth

Sugar beet and grain amaranths belong to the plant order Caryophyllales, which, until recently, has been relatively sparse in staple edible crops and, hence, is underrepresented among sequenced genomes of plants. The order includes green leafy vegetables like spinach, new grains like amaranth, quinoa and buckwheat, ornamental plants exhibiting vibrant shades of leaves and inflorescence like joyweeds, medicinal herbs like epazote, notorious weeds like pigweeds, and succulents like prickly pear. Despite being a treasure trove of desirable traits much sought after in crops under other plant orders and being home for some very highly nutritious species, funding for large-scale genomics studies under the order Caryophyllales remain limited to Sugar beet. The completed genome of Sugar beet and the draft genome of one of the grain amaranths, both reported in 2014, offer the much needed genomic resources to advance molecular level studies on the diverse desirable phenotypes displayed under this order. Beta vulgaris is a C3 edible dicot with roots rich in sugar. Amaranthus hypochondriacus, on the other hand, is a C4 dicot with edible leaves, stem and seeds, offering a rich source of lysine, folic acid and other minerals. Here we present a comparative genomic study of B. vulgaris and A. hypochondriacus including differential expression of genes involved in lysine biosynthesis, C3-C4 cycles, study of betalain pigments, and repeat elements.