Applications of Genomic Tools in Plant Breeding: Crop Biofortification

Abstract

Crop breeding has mainly been focused on increasing productivity, either directly or by decreasing the losses caused by biotic and abiotic stresses (that is, incorporating resistance to diseases and enhancing tolerance to adverse conditions, respectively). Quite the opposite, little attention has been paid to improve the nutritional value of crops. It has not been until recently that crop biofortification has become an objective within breeding programs, through either conventional methods or genetic engineering. There are many steps along this long path, from the initial evaluation of germplasm for the content of nutrients and health-promoting compounds to the development of biofortified varieties, with the available and future genomic tools assisting scientists and breeders in reaching their objectives as well as speeding up the process. This review offers a compendium of the genomic technologies used to explore and create biodiversity, to associate the traits of interest to the genome, and to transfer the genomic regions responsible for the desirable characteristics into potential new varieties. Finally, a glimpse of future perspectives and challenges in this emerging area is offered by taking the present scenario and the slow progress of the regulatory framework as the starting point.

Keywords: biofortification; breeding; cisgenesis; crop; intragenesis; metabolic GWAS (mGWAS); single-nucleotide polymorphisms (SNPs); trangenesis.

Figure 1

Comparison of the SNP genotyping techniques most commonly used in crops grouped by the platforms in the throughput level.

Figure 2

Construction of breeding populations: (A) recombinant inbred lines (RILs); (B) near isogenic lines (NILs); (C) advanced backcross; and (D) their use for Genomic Selection (GS). Only some of the possible crossing designs are shown.

Figure 3

Schematic representation of three modern biotechnology techniques to introduce allelic variants of interest in a recipient organism: (A) transgeneis; (B) cisgenesis; and (C) intragenesis.