Elimination of zero-repeat subunit in allergenic seed protein 13S globulin using the novel allele GlbNB2 in common buckwheat ( Fagopyrum esculentum Moench)

Common buckwheat ( Fagopyrum esculentum Moench) seeds contain 13S globulin, the zero -repeat subunit of which is trypsin-resistant and allergenic. Here, its two novel alleles were analyzed for development of hypoallergenic plants. The GlbNC allele has a Miniature Inverted -repeat Transposable Element (MITE) -like insertion in the 4th exon. However, most of the insertion was spliced -out, resulting in accumulation of zero -repeat subunit in GlbNC homozygotes. Meanwhile, the GlbNB2 has a 164 -bp insertion in the 3rd exon, resulting in no accumulation of zero -repeat subunit in GlbNB2 homozygotes (NB2_homo). Both the insertion sequences were predicted to form a hairpin -like structure, and that of GlbNB2 was more rigid than that of GlbNC . Trypsin digestion in NB2_homo showed that the alpha polypeptide of Met -rich subunit is also hard to digest, that is a next target to eliminate for hypoallergenic buckwheat development.