Structure and diversity of 13S globulin zero-repeat subunit, the trypsin-resistant storage protein of common buckwheat (Fagopyrum esculentum M.) seeds.

The zero-repeat subunit of 13S globulin, which lacks tandem repeat inserts, is trypsin-resistant and suggested to show higher allergenicity than the other subunits in common buckwheat (Fagopyrum esculentum Moench). To evaluate allelic variations and find novel alleles, the diversity of the zero-repeat genes was examined for two Japanese elite cultivars and 15 Pakistani landraces. The results demonstrated that two new alleles GlbNA1 and GlbNC1, plus three additional new alleles GlbNA2, GlbNA3, and GlbND, were identified besides the already-known GlbNA, GlbNB, and GlbNC alleles. In the Pakistani landraces, GlbNA was the most dominant allele (0.60-0.88 of allele frequency) in all except one landrace, where GlbNB was the most dominant allele (0.50 of allele frequency). Similar to GlbNC, the alleles GlbNA2 and GlbNA3 had extra ~200 bp MITE-like sequences around the stop codon. Secondary structure predictions of a sense strand demonstrated that the extra ~200 bp sequences of GlbNC, GlbNA2, and GlbNA3 can form rigid hairpin structures with free energies of -78.95, -67.06, and -29.90 kcal/mol, respectively. These structures may affect proper transcription and/or translation. In the GlbNC homozygous line, no transcript of a zero-repeat gene was detected, suggesting the material would be useful for developing hypoallergenic buckwheat.

Two novel quantitative trait loci affecting the variation in leaf photosynthetic capacity among soybeans.

There is a large variation in CO2 assimilation rate per unit of leaf area (A) within or among crop species, which can be exploited to improve A by elucidating the mechanisms underlying such variation. The objective of the present study is to elucidate the genetic factors affecting the variation in leaf photosynthetic capacity among soybeans. Here, we conducted field experiments over three years, using Enrei, a leading variety in Japan, Peking, a landrace from China and the chromosome segment substitution lines derived from their progenies. The gas exchange measurements were conducted to evaluate A among soybean. Peking showed higher A than Enrei after the flowering in all the years. The genetic analysis identified two novel quantitative trait loci (QTLs) related to variation in A, which were located on chromosome 13 (qLPC13) and 20 (qLPC20). The Peking allele at qLPC13 increased A by 8.3 % in the Enrei genetic background, while the Peking allele at qLPC20 decreased A by 15.3 %. The present study is the first report on QTLs affecting a genotypic variation in leaf photosynthetic capacity among field-grown soybeans. The identification of the causal genes in these QTLs can provide a novel strategy to enhance leaf photosynthetic capacity with soybean breeding.