Digital Absolute Gene Expression Analysis of Essential Starch-Related Genes in a Radiation Developed Amaranthus cruentus L. Variety in Comparison with Real-Time PCR

We investigated the expression pattern of four major starch genes at different seed developmental stages in the radiation-bred amaranth variety “Pribina” (Amaranthus cruentus L.) and corresponding control genotype “Ficha” (Amaranthus cruentus L.). Two platforms were used and compared for the gene expression analysis of GBSSI, SSSI, SBE, and DBE amaranth genes, including a standard quantitative real-time PCR (qPCR) technique and relatively novel droplet digital PCR (ddPCR) assay. In our conditions, both methods showed great accuracy and revealed higher expression of the investigated genes in the mutant variety than in the control genotype. Here we report for the first time, a ddPCR gene expression assay for the cultivated grain amaranth, as the most important group of the species in the genus Amaranthus.