Marker-Assisted Breeding Techniques for the Development of Gluten-Free Wheat Varieties: A Comprehensive Review

Ingestion of gluten proteins from wheat, barley and rye poses a significant health risk. The sole treatment for various disease is a lifelong adherence to a strict gluten-free diet. Conventional breeding methods have limitations in producing wheat varieties that maintain baking quality due to the complexity of the wheat genome and the multitude of gluten genes. This review explores the use of RNA interference (RNAi) silencing and CRISPR/Cas9 gene editing techniques. Efficient screening and selection processes for identifying lines with reduced celiac disease epitopes at both the DNA and protein levels, as well as maintaining baking quality, are discussed. The integration of gene editing for the production of wheat products holds significant potential in meeting the growing demand for safer dietary options while ensuring compliance with regulatory standards and addressing the complex challenges associated with disease management. Marker-assisted selection (MAS) offers several advantages over conventional selection methods in plant breeding, including timesaving, cost-effectiveness and goal-oriented outcomes. This review aims to delineate various molecular markers, encompassing sequence-tagged sites (STS), simple sequence repeats (SSR), genotyping by sequencing (GBS), single nucleotide polymorphism (SNP) arrays, exome capture, Competitive Allele Specific PCR (KASP), cleaved amplified polymorphic sequences (CAPS), semi-thermal asymmetric reverse PCR (STARP), and genotyping by target sequencing (GBTS). Additionally, we compile quantitative trait loci (QTL)/genes and their associated markers, which hold potential utility in MAS applications. The rapid advancement of wheat genomics is poised to expedite marker development, QTL mapping, gene cloning, and wheat breeding processes.