A spelt-specific gamma-gliadin gene: discovery and detection

Polymerase chain reaction (PCR) primers GAGS and GAG6 were designed based o n published gamma-gliadin gene sequences and applied to 35 cultivars of clo sely related spelt (Triticum spelta L.) and hexaploid wheat (I: aestivum L. ). Eight tetraploid durum wheat (T. durum Desf.) cultivars were included in the analysis. The obtained PCR products originated from two gamma-gliadin genes which were mapped to homeologous chromosomes 1B and 1D and termed GAG 56B and GAG56D, respectively. Two alleles of GAG56D differing in a 9-bp del etion/duplication and single nucleotide polymorphism were found. The 18 spe lts tested and wheat cultivar 'Chinese Spring' were discovered to carry a p reviously unknown gamma-gliadin gene, while 16 wheat cultivars possessed it s longer, already published allele. Two PCR-based detection systems for the diagnostic alleles were developed and applied. The occurrence of two allel es of GAG56B among the investigated durum wheats correlated with their expr ession of gluten quality markers gamma-gliadins 42 or 45.