Tartary buckwheat (Fagopyrum tataricum) is an annual coarse cereal from the Polygonaceae family, known for its high content of flavonoid compounds, particularly rutin. But so far, the mechanisms of ...the flavonoid transport and storage in Tartary buckwheat (TB) remain largely unexplored. This study focuses on ATP-binding cassette transporters subfamily C (ABCC) members, which are crucial for the biosynthesis and transport of flavonoids in plants. The evolutionary and expression pattern analyses of the ABCC genes in TB identified an ABCC protein gene, FtABCC2, that is highly correlated with rutin synthesis. Subcellular localization analysis revealed that FtABCC2 protein is specifically localized to the vacuole membrane. Heterologous expression of FtABCC2 in Saccharomyces cerevisiae confirmed that its transport ability of flavonoid glycosides such as rutin and isoquercetin, but not the aglycones such as quercetin and dihydroquercetin. Overexpression of FtABCC2 in TB hairy root lines resulted in a significant increase in total flavonoid and rutin content (P < 0.01). Analysis of the FtABCC2 promoter revealed potential cis-acting elements responsive to hormones, cold stress, mechanical injury and light stress. Overall, this study demonstrates that FtABCC2 can efficiently facilitate the transport of rutin into vacuoles, thereby enhancing flavonoids accumulation. These findings suggest that FtABCC2 is a promising candidate for molecular-assisted breeding aimed at developing high-flavonoid TB varieties.
The present study investigated the effects of gaseous ozone treatment on the structural, physicochemical and in vitro digestible properties of Tartary buckwheat starch (TBS). The results showed that ...gaseous ozone treatment increased the detectable carbonyl and carboxyl groups content, improved the amylose content, and decreased pH of TBS. The granule microstructures of native TBS and ozone-treated TBS (OTBS) were characterized by SEM, CLSM and small-angle X-ray scattering (SAXS), showing that OTBS exhibited a reduced granule smoothness and integrity, lessened coloration area of FITC fluorescent as well as decreased crystalline layer and increased amorphous region. FTIR and XRD results revealed that appropriate time of gaseous ozone treatment (2.5 and 7.5 min) enhanced short-range and long-range order structure due to the increased intermolecular oxidation cross-linking, whereas over treatment (15 and 20 min) caused degradation of the starch. With the increasing treatment time, apparent viscosity increased while breakdown viscosity, setback viscosity, swelling power and solubility decreased. OTBS exhibited a higher gelatinization enthalpy (ΔH) and a better viscoelasticity after gelation (6% OTBS gel, w/w). Additionally, OTBS-2.5 and OTBS-7.5 showed a decreased rapidly digested starch (RDS) content and increased resistant starch (RS) content, indicating that the digestible properties of two oxidized starches was decreased, which provide a feasible way to develop TBS as a new modified starch source.
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•Gaseous ozone changed the granule morphology of Tartary buckwheat starch.•Ordered and double helices structures of starch were enhanced by moderate ozone.•The formation of more carbonyl and carboxyl groups in starch were detected.•The modified starches showed stronger gelling property and weaker retrogradation.•Moderate oxidized starch possessed lower digestibility than that of native starch.
Drought is becoming a common threat to crop production. To combat this stress and ensure global food security, the identification and utilization of excellent drought-resistant genes are crucial for ...developing drought-resistant crop varieties. However, sugar transporters are known to be involved in stress tolerance in many plants, while the sugar transporter gene family of Tartary buckwheat has not been systematically analyzed yet. In this study, 140 sugar transporter genes were identified from the ‘Pinku’ Tartary buckwheat genome and classified into ten subfamilies. Structural analysis showed that subfamily SGB/pGlcT had the highest number of introns compared to other subfamilies, and abundant abiotic stress-related cis-acting elements existed in the promoter region. Collinear analysis revealed that FtSUT7, FtSTP28, FtPLT1, and FtINT2 genes are relatively ancient. The expression of sugar transporter genes was screened under various abiotic stresses which revealed the association of stress tolerance with different sugar transporter genes, i.e., FtERD23, FtINT2, FtpGlcT2, and FtSTP27. Further, it was observed that the overexpression of FtERD23 maintains osmotic pressure through glucose transport, which may enhance drought stress tolerance. Moreover, gene co-expression analyses using WGCNA and FCMA identified six transcription factors that may regulate FtERD23 expression and are involved in plant drought tolerance. In summary, this systematic analysis provides a theoretical basis for further functional characterization of sugar transporter genes to improve drought tolerance in Tartary buckwheat and its related species.
•A total of 722 metabolites were identified in the seeds of eight buckwheat varieties.•84 key active ingredients and 78 active pharmaceutical ingredients were identified.•Tartary and common buckwheat ...differ in metabolite composition.•155 and 48 biomarkers were identified in Tartary and common buckwheat, respectively.•Tartary buckwheat is a promising source with higher health-promoting value.
Tartary buckwheat has higher health-promoting value than common buckwheat. However, the related metabolites information except flavonoids is largely deficient. Here, we compared the seed metabolomes of the two species using a UHPLC-QqQ-MS-based metabolomics approach. In total, 722 metabolites were obtained, of which 84 and 78 were identified as the key active ingredients of Traditional Chinese Medicines and the active pharmaceutical ingredients for six major diseases-resistance, respectively. Comparative analysis showed there were obviously difference in metabolic profiles between the two buckwheat species, and further found 61 flavonoids and 94 non-flavonoids metabolites displayed significantly higher contents (≥2 fold) in Tartary buckwheat than in common buckwheat. Our results suggest that Tartary and common buckwheat seeds are rich in metabolites beneficial to human health, and non-flavonoids metabolites also contributed to Tartary buckwheat's higher health-promoting value than common buckwheat. This study provides valuable information for the development of new functional foods of Tartary buckwheat.
Starch-polyphenols complex with unique physicochemical and functional properties has gained research interests. As a method of physical modification, plasma treatment leads to smaller fragments of ...starch, which increases the possibility of binding with polyphenols. In this study, pregelatinized plasma-modified Tartary buckwheat starch (pre-TBS-P), as a new material, was combined with quercetin forming complexes (pre-TBS-P-Q). The rheological and thermal properties, and digestibility of pre-TBS-P-Q were investigated. Results show that quercetin complexation increased the consistency coefficient and decreased the flow behavior index. A more compact and stable structure after combining quercetin was observed using SEM and TGA. The results of XRD and FT-IR identified that quercetin was bound to starch through hydrogen bonds, forming the non-inclusive complex with higher crystallinity. Compared with pregelatinized Tartary buckwheat starch (pre-TBS), the digestion rate of both pre-TBS-P and pre-TBS-P-Q decreased. The velocity constant in the first-order digestion ranked as pre-TBS < pre-TBS-P < pre-TBS-P-Q. Conclusively, using the combination of plasma treatment and complexation with quercetin, the digestion velocity of pre-TBS-P-Q complex decreased due to the increased viscosity of starch solution, as well as, the enhanced crystallinity and compactness of starch granules.
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•Plasma-modified Tartary buckwheat starch formed non-inclusive complex with quercetin.•The effect of quercetin addition was more distinct together with plasma treatment.•The complex exhibited a pseudoplastic and shear-thinning behavior.•Starch digestion decreased by combining plasma treatment and quercetin complexation.•This study provides new insights into the production of anti-digestion starch.
Nitrogen fertilizer is a crucial factor affecting the growth and grain quality of Tartary buckwheat. This study was to investigate the synthesis, accumulation, and physicochemical properties of ...Tartary buckwheat starches under four nitrogen levels (0, 90, 180, 270 kg N ha−1). The results showed that activities of four key enzymes, starch contents all first increased and then decreased with increasing nitrogen levels, and peaked at 180 kg N ha−1. All the starches showed typical A-type, while higher nitrogen levels significantly increased the relative crystallinity. The viscosities significantly decreased, onset, peak, and conclusion first decreased and then increased, while pasting temperature and gelatinization enthalpy increased with increasing nitrogen levels. Nitrogen fertilizer and year had significant effects on the synthesis, accumulation and physicochemical properties of Tartary buckwheat starch, and the nitrogen level of 180 kg N ha−1 was more suitable for planting in the northern area of the Loess Plateau.
•Activities of key enzymes for starch synthesis first increased and then decreased.•Amylose content positively correlated with granule bound starch synthase activity.•Tartary buckwheat starches under different nitrogen levels all showed A-type.•Gelatinization enthalpies significantly increased with increasing nitrogen levels.•Nitrogen level of 180 kg N ha−1 was recommended for Tartary buckwheat planting.
Tartary buckwheat dough (120 g) was used to produce steamed tartary buckwheat bread (STB). Alterations in antioxidant capacity and α-glucosidase inhibitory activity levels, and the concentrations of ...various flavonoid compounds, were investigated after each processing stage. It was identified that aglycone (quercetin and kaempferol) levels were increased after dough formation and fermentation stages. These stages were also associated with higher antioxidant capacity and α-glucosidase inhibitory activity. After steaming, flavonoid compound and antioxidant activity levels were slightly decreased in comparison to those observed after dough formation and fermentation steps, although they were higher than in raw flour.
To clarify the anti-diabetic potential of individual flavonoid compounds, the antioxidant and α-glucosidase inhibitory activities of four distinct flavonoids were investigated. The results of the present study revealed that aglycones have more potent anti-diabetic effects than their corresponding glycosides, which may explain the change in antioxidant and α-glucosidase inhibitory activities of samples taken after the different processing stages. Correlation analysis also indicated that flavonoids’ being in their aglycone form was positively associated with higher antioxidant and α-glucosidase inhibitory activities. Overall, these data suggest that deglycosylation of flavonoids, which occurs during the preparation of STB, contributes to higher hypoglycemic potential in tartary buckwheat bread products.
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•Healthy substance variation is studied in steamed tartary buckwheat bread process.•Aglycone content increases during dough formation and fermentation.•Deglycosylation contributes to health-promoting property of tartary buckwheat bread.
Steam explosion (SE) is an efficient technology to disrupt the hard structure of cereal bran and improve its biological activities. In this study, different intensities of SE were applied in Tartary ...buckwheat bran (TBB) to study 1) the changes of bran structures and 2) the release efficiency of polyphenols. Results illustrated SE diminished the contents of free polyphenols in TBB by 6.24–21.65%, while the bound ones were increased by 15.23–120.81%. The in vitro study demonstrated that the scavenging organic free radical DPPH· activity and oxygen radical absorption capacity (1.6 MPa for 60 s) of total polyphenols were significantly improved. Furthermore, the free quercetin contents were increased by 4–6 times and the free rutin contents were decreased by 60–75%. SE made TBB particle size changed, specific surface area increased, thermal stability enhanced, but polyphenol oxidase (PPO) activity decreased. All the results suggested that SE could enhance the antioxidant activity of TBB polyphenols through changing the constituent proportion, structure, thermal stability, and enzyme activity of bran.
•Steam explosion increased the bound polyphenols contents in Tartary buckwheat bran.•Steam explosion increased the release of free quercetin.•Steam explosion improved antioxidant capacity of polyphenols.•Steam explosion enhanced thermo stability and decreased PPO activity.
•Rutin from tartary buckwheat hull was efficiently extracted by UAE with NADESs.•NADES can be reused during the extraction.•The biocompatibility and biodegradability of NADESs were evaluated.•NADES ...can be used as a green and safe extraction solvent for bioactive ingredients.
In this study, an efficient extraction technique using a combination of ultrasound and natural deep eutectic solvents (NADESs) was developed. Some basic physical properties, including viscosity, polarity, and solubility, of thirteen NADESs prepared from natural components were investigated systematically. Results show that the solubility of rutin increased in choline chloride- and glycerol-based NADESs by 660–1577times compared to water. NADESs with high rutin extractability can be designed by combining NADESs components. A maximum of 9.5mg/g rutin was extracted from tartary buckwheat hull with extraction efficiencies of 95%. NADESs can be recovered and recycled. In addition, the biocompatibility and biodegradability of the tested NADESs were also evaluated. The results demonstrated that these NADESs were excellent solvents with extremely low toxicities and favorable biodegradabilities. Our findings suggest that NADESs can be used as green solvents for the extraction of bioactive ingredients.
