Comparative Study of Lysine Biosynthesis in Edible Grains of Caryophyllales

Grain amaranths, members of Amaranthaceae family of plants, are C4 dicots that are known to produce edible seeds with lysine content as high as in milk. Given that lysine is the most limiting essential amino acid in the cereals consumed, the obscurity of grain amaranths during modern times, which were domesticated for human consumption some thousands of years ago during the Aztec and the Inca civilization, is inconceivable. Efforts in the past to improve lysine content in rice and wheat have failed in the past because of the inverse correlation between lysine content and yield. In this context, species under grain amaranth can act as model plants shedding light on the, yet unexplored, mechanisms by which plants can break the inherent inverse correlation between high-lysine phenotype and yield.  Here, we present the progress made in studying the expression profile of genes involved in lysine biosynthesis and the corresponding lysine content in Amaranthus hypochondriacus as compared to that in other edible crops. We have extracted near-full length cDNA for genes involved in lysine biosynthesis in A. hypochondriacus using in-house scripts from the draft genome and transcriptomes generated for the species in-house and measured heir expression levels using RNA-seq. Further, horizontal profiling in grain amaranths and vertical profiling in A. hypochondriacus of lysine content is being done using Ultra-Fast Liquid Chromatography to correlate the gene expression levels with the lysine content.