TILLING in Cereal Crops for Allele Expansion and Mutation Detection by Using Modern Sequencing Technologies

A substantial increase in yield of food crops is crucial to feeding the burgeoning global population. There is a need to introduce new breeding strategies that will accelerate the average phenotypic values of crop plants. The use of induced mutations coupled with modern genomics tools is an effective strategy for identifying and manipulating genes for crop improvement. High-throughput TILLING (Targeting Induced local Lesions IN Genomes) methodology, detects mutations in mutagenized populations, and EcoTILLING identifies single nucleotide polymorphisms (SNPs) within a natural population and associates these variations with traits of breeding interest. The main advantage of these techniques as a “reverse genetics” strategy is that they can be applied to any species regardless of genome size and ploidy level. In cereals, several space-induced and EMS-induced mutant populations have been used to identify mutants with important traits including salinity tolerance, grain size, and recombinant crossovers via TILLING by sequencing (TbyS). Genes such as TaSSIV, which plays an important role in starch granule formation, and Pin a and Pin b, which have been associated with kernel hardness in wheat, have been exploited in cereals via the EcoTILLING approach. This review focused on the functions and challenges of TILLING and the relation of TILLING to next-generation sequencing (NGS) technologies which help to exploit the induced mutations and their potential applications in cereal crops.