Unravelling rutin content of tartary buckwheat of north western Himalayas and insights into nucleotide polymorphisms in PAL gene to infer the associations with rutin biosynthesis

Buckwheat (Fagopyrum spp.) has immense nutritional and nutraceutical potential. All the plant parts of buckwheat possess various metabolites, such as rutin, quercetin, vitexin etc. The high content of rutin in this pseudo cereal crop strongly adapts it to grow under adverse environments. In the present study 50 germplasm lines of Fagopyrum tataricum were used for estimation of seed endosperm rutin content through HPLC. Furthermore, molecular analysis of PAL gene (Phenylalanine Ammonia Lyase), an upstream gene in rutin biosynthesis pathway was targeted for detection of SNPs to understand the variations in the concentrations of seed endosperm rutin content, among tartary buckwheat genotypes with highest and lowest seed endosperm rutin content. Three primer pairs were employed for amplification of PAL gene for F. tartaricum (covering whole gene) followed by sequencing. Rutin concentration in seed endosperm of F. tartaricum ranged from 194.86 to 1403.22 ppm with an average of 617.06 ppm. Highest rutin concentration was found in genotype BWZ90 and lowest in BWZ16. Significant variations were observed in the seed endosperm rutin content among the genotypes of tartary buckwheat. Furthermore, alignment of PAL gene sequences of genotypes with high seed endosperm rutin content and low seed endosperm rutin content revealed variations at 21 polymorphic sites. The amino acid sequences obtained from the nucleotide sequences were also aligned and the variations were detected at 19 positions. The putative protein structure showed conformational changes among predicted proteins from two contrasting genotypes for endosperm rutin content. We here established an inventory of seed endosperm rutin content of tartary buckwheat. This study also provided insights about role of these SNPs in rutin biosynthesis. Furthermore, this information can be used for breeding buckwheat for high metabolite contents.