Genome-wide identification and expression analysis of 11S seed storage protein genes in tartary buckwheat (Fagopyrum tataricum)

Based on whole genome data of tartary buckwheat (Fagopyrum tataricum (L.) Gaertn), we used bioinformatics to exploit nine 11S seed storage protein genes, and analyzed their identification, location, protein structure, phylogenetic relationship, and expression. Results showed that the encoded protein lengths of these nine genes ranged from 189 to 914 aa, the isoelectric points ranged from 5.18 to 9.82, and the molecular weights ranged from 21.27 to 103.33 kD. Sequence alignment showed that one 11S seed storage protein (sample1_00009513-RA) contained only one cupin conservative domain, with the other eight members all containing two cupin conservative domains. In addition, there were 14 conservative amino acid residues in the cupin domain between tartary buckwheat and Arabidopsis. Location analysis demonstrated that these genes were mapped on six linkage groups of the tartary buckwheat genome (Megascaffold2/5 and scaffold77/344/395/861). Prediction analysis suggested that the tartary buckwheat 11S seed storage proteins exhibited two types of protein structure. The phylogenetic relationship of the 11S seed storage proteins from tartary buckwheat and six other species (Arabidopsis, peanut, soybean, almond, walnut, and sesame) indicated that these proteins could be classified into three groups, containing four pairs of paralogous and three pairs of orthologous. Compared with the reported allergic storage proteins in tartary buckwheat and 11S allergens from five other species (peanut, soybean, almond, walnut, and sesame), five 11S seed storage proteins demonstrated high similarity, with the highest similarity found with walnut; however, further experiments are needed to clarify whether these five members are food allergens or not. RNA-Seq analysis revealed that only four members (sample1_00018411-RA,sample1_00026786-RA,sample1_00021674-R,sample1_00022718-RA) had high expression levels in milk stage seeds of two kinds of buckwheat, and were more highly expressed in ‘Daku 1’ than in ‘Datian 1’.