Tartary buckwheat (Fagopyrum tataricum) is considered a profitable crop that possesses medicinal properties, because of its flavonoid compounds. However, the dehulling issue is becoming the bottleneck for consumption of Tartary buckwheat seed. In this study, we investigated the relation between dehulling efficiency and content of lignin and cellulose in the seed hull. Moreover, the untargeted metabolomics analysis, including partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA), were performed to examine the pattern of metabolic changes in the hull of Tartary buckwheat seeds, XQ 1 and MQ 1, during seed development using gas chromatography mass spectrometry (GC-MS). In mature seed hull the accumulation of highest lignin and lowest cellulose were observed in the hull of MQ 1 seed, a dehulling-friendly variety with highest dehulling efficiency (93%), than that in other dehulling recalcitrant varieties, such as XQ 1 with a range of dehulling efficiency from 2% to 6%. During seed development, the total content of lignin and cellulose increased. MQ 1 and XQ 1 displayed a similar trend in the change of lignin and cellulose that the content was decreased in lignin and increased in cellulose. PCA result showed the metabolic differentiations between MQ 1 and XQ 1 during seed development. The results of our study suggest the compensatory regulation of lignin and cellulose deposition in the hull of mature and developing seed, and deviation of MQ 1 from the ratio of lignin to cellulose of other dehulling recalcitrant varieties may have been a contributing factor that resulted in the dehulling differentia.

Curcuma alismatifolia is an important ornamental plant of significant economic value, while the floral fragrance has been rarely investigated, leading to a lack of knowledge about the floral scent. By performing metabolomic and transcriptomic analyses, we investigated the variation of 906 volatile organic compounds (VOCs) in florets of eight C. alismatifolia cultivars and four different developmental stages of “Chiang Mai Pink” (CMP). The metabolite profiling revealed that the terpenoid group (213 out of 906) was the predominant VOC, accounting for 33.5% and 43.4% of total VOC contents in the florets of different cultivars and developmental stages, respectively. Sweet and woody were the predominant odors not only in different cultivars but also during developmental stages. The varied intensities of other odors contributed to forming odor diversities in C. alismatifolia floret. We uncovered seven terpenoid synthetase (TPS) genes and four MYB genes of significant association with the biosynthesis of terpenoids in eight cultivars and floret development, respectively. We performed an activity assay on four selected TPS genes and identified that Chr15HA1352 and Chr15HA2528 are responsible for the biosynthesis of α-farnesene. The significant association between the MYB gene (Chr03HA28) and seven terpenoids can be observed among different cultivars and during different developmental stages. These findings highlight the varying floral scents in different cultivars and floret development and suggest the potential roles of identified TPS and MYB genes in the biosynthesis of terpenoids in C. alismatifolia.