Nutrient and metabolite characteristics of the husk, bran and millet isolated from the foxtail millet (Setaria italica L.) during polishing.

The utilization of byproducts from foxtail millet polishing can reduce food loss and waste. Thus, it is necessary to know the chemical compounds from the millet and the segregation of the layers. The nutrients including minerals were compared among the husk, bran, and millet, and a LC-MS metabolomics analysis was also performed among them. The results showed that the protein, crude fat and 4 fatty acids, seven minerals, the nitrogen-containing compounds and phenolic acids were at much higher levels in the bran part than the husk and millet, whereas the husk only contained higher levels of dietary fibre, and some minerals. The millet section, as the edible part, contained the lowest level of chemical constituents. It illustrated that the bran part contained more functional and nutritional components than the millet and husk part. Therefore, the bran of the foxtail millet should be a food resources instead of wasting.

Genome-wide association study reveals genetic loci for ten trace elements in foxtail millet (Setaria italica).

KEY MESSAGE: One hundred and fifty-five QTL for trace element concentrations in foxtail millet were identified using a genome-wide association study, and a candidate gene associated with Ni-Co-Cr concentrations was detected. Foxtail millet (Setaria italica) is an important regional crop known for its rich mineral nutrient content, which has beneficial effects on human health. We assessed the concentrations of ten trace elements (Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn) in the grain of 408 foxtail millet accessions. Significant differences in the concentrations of five elements (Ba, Co, Ni, Sr, and Zn) were observed between two subpopulations of spring- and summer-sown foxtail millet varieties. Moreover, 84.4% of the element pairs exhibited significant correlations. To identify the genetic factors influencing trace element accumulation, a comprehensive genome-wide association study was conducted, identifying 155 quantitative trait locus (QTL) for the ten trace elements across three different environments. Among them, ten QTL were consistently detected in multiple environments, including qZn2.1, qZn4.4, qCr4.1, qFe6.3, qFe6.5, qCo6.1, qPb7.3, qPb7.5, qBa9.1, and qNi9.1. Thirteen QTL clusters were detected for multiple elements, which partially explained the correlations between elements. Additionally, the different concentrations of five elements between foxtail millet subpopulations were caused by the different frequencies of high-concentration alleles associated with important marker-trait associations. Haplotype analysis identified a candidate gene SETIT_036676mg associated with Ni accumulation, with the GG haplotype significantly increasing Ni-Co-Cr concentrations in foxtail millet. A cleaved amplified polymorphic sequence marker (cNi6676) based on the two haplotypes of SETIT_036676mg was developed and validated. Results of this study provide valuable reference information for the genetic research and improvement of trace element content in foxtail millet.

Effect of Different Fertilizer Types on Quality of Foxtail Millet under Low Nitrogen Conditions.

In order to clarify the effect of different fertilizers on foxtail millet quality under low nitrogen conditions, we used JGNo.21 and LZGNo.2 as experimental materials and set up five treatments, including non-fertilization, nitrogen, phosphorus, compound, and organic fertilizers, to study the regulation of different fertilizer types on agronomic traits, nutrient fractions, and pasting characteristics of foxtail millet under low nitrogen conditions. Compared with the control, all of the fertilizers improved the agronomic traits of JGNo.21 to a certain extent. Nitrogen and compound fertilizer treatments reduced the starch content of JGNo.21; the starch content was reduced by 0.55% and 0.07% under nitrogen and compound fertilizers treatments. Phosphorus and organic fertilizers increased starch content, and starch content increased by 0.50% and 0.56% under phosphorus and organic fertilizer treatments. The effect of each fertilizer treatment on protein content was completely opposite to that of starch; different fertilizer treatments reduced the fat content of JGNo.21 and increased the fiber content. Among them, nitrogen and phosphorus fertilizers increased the yellow pigment content; the yellow pigment content increased by 1.21% and 2.64% under nitrogen and phosphorus fertilizer treatments. Organic and compound fertilizers reduced the content of yellow pigment; the yellow pigment content was reduced by 3.36% and 2.79% under organic and compound fertilizer treatments. Nitrogen and organic fertilizers increased the fat content of LZGNo.2; the fat content increased by 2.62% and 1.98% under nitrogen, organic fertilizer treatment. Compound and phosphorus fertilizer decreased the fat content; the fat content decreased by 2.16% and 2.90% under compound and phosphorus fertilizer treatment. Different fertilizer treatments reduced the cellulose and yellow pigment content of LZGNo.2. The content of essential, non-essential, and total amino acids of JGNo.21 was increased under compound and nitrogen fertilizer treatments and decreased under organic and phosphorus fertilizer treatments. The content of essential, non-essential, and total amino acids of LZGNo.2 was significantly higher under compound, nitrogen, and organic fertilizer treatments compared with control and significantly decreased under phosphorus fertilizer treatments. Nitrogen and compound fertilizer treatments significantly reduced the values of peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, and pasting time of each index of JGNo.21; phosphorus and organic fertilizer treatments improved the values of each index. In contrast, the pasting viscosity of LZGNo.2 increased under phosphorus fertilizer treatment and decreased under nitrogen fertilizer treatment. Reasonable fertilization can improve the quality of foxtail millet, which provides a scientific theoretical basis for improving the quality of foxtail millet.

Gastroprotective Effect of Isoferulic Acid Derived from Foxtail Millet Bran against Ethanol-Induced Gastric Mucosal Injury by Enhancing GALNT2 Enzyme Activity.

Excessive alcohol consumption has led to the prevalence of gastrointestinal ailments. Alleviating gastric disorders attributed to alcohol-induced thinning of the mucus layer has centered on enhancing mucin secretion as a pivotal approach. In this study, foxtail millet bran polyphenol BPIS was divided into two components with MW < 200 D and MW > 200 D by molecular interception technology. Combined with MTT, cell morphology observation, and trypan blue staining, isoferulic acid (IFA) within the MW < 200 D fraction was determined as the effective constituent to mitigate ethanol-induced damage of gastric epithelial cells. Furthermore, a Wistar rat model with similar clinical features to alcohol-induced gastric mucosal injury was established. Then, gastric morphological observation, H&E staining, and assessments of changes in gastric hexosamine content and gastric wall binding mucus levels were carried out, and the results revealed that IFA (10 mg/Kg) significantly ameliorated alcohol-induced gastric mucosal damage. Finally, we applied techniques including Co-IP, molecular docking, and fluorescence spectroscopy and found that IFA inhibited the alcohol-induced downregulation of N-acetylgalactosamintransferase 2 (GALNT2) activity related to mucus synthesis through direct interaction with GALNT2 in gastric epithelial cells, thus promoting mucin synthesis. Our study lays a foundation for whole grain dietary intervention tailored to individuals suffering from alcoholic gastric mucosal injury.

Experimental and drying kinetics study on millet particles by a pulsating fluidized bed dryer.

This research studies experimentally the drying of foxtail millet in a pulsation-assisted fluidized bed. The effects of temperature and pulsating flow frequency on millet drying are examined. The experiments are conducted at temperatures of 40 °C, 50 °C, and 60 °C for three pulsating frequencies of 0.5, 1, and 2.5 Hz and continuous flow. The best result is obtained for drying with a frequency of 1 Hz. It shows that the pulsating flow is more effective at 50 °C as compared to other temperatures. Four reliable semi-empirical models are used for predicting the moisture reduction during drying process. Among the fitted dynamic models, the model that has the maximum correlation coefficient (R 2 ) and minimum sum of squares of error (SSE) and root mean squared error (RMSE) and well able to predict the behavior of millet drying in the whole process was chosen.

Utilizing machine learning and bioinformatics analysis to identify drought-responsive genes affecting yield in foxtail millet.

Drought stress is a major constraint on crop development, potentially causing huge yield losses and threatening global food security. Improving Crop's stress tolerance is usually associated with a yield penalty. One way to balance yield and stress tolerance is modification specific gene by emerging precision genome editing technology. However, our knowledge of yield-related drought-tolerant genes is still limited. Foxtail millet (Setaria italica) has a remarkable tolerance to drought and is considered to be a model C4 crop that is easy to engineer. Here, we have identified 46 drought-responsive candidate genes by performing a machine learning-based transcriptome study on two drought-tolerant and two drought-sensitive foxtail millet cultivars. A total of 12 important drought-responsive genes were screened out by principal component analysis and confirmed experimentally by qPCR. Significantly, by investigating the haplotype of these genes based on 1844 germplasm resources, we found two genes (Seita.5G251300 and Seita.8G036300) exhibiting drought-tolerant haplotypes that possess an apparent advantage in 1000 grain weight and main panicle grain weight without penalty in grain weight per plant. These results demonstrate the potential of Seita.5G251300 and Seita.8G036300 for breeding drought-tolerant high-yielding foxtail millet. It provides important insights for the breeding of drought-tolerant high-yielding crop cultivars through genetic manipulation technology.

Identification, molecular evolution, codon bias, and expansion analysis of NLP transcription factor family in foxtail millet (Setaria italica L.) and closely related crops.

The NODULE-INCEPTION-like protein (NLP) family is a plant-specific transcription factor (TF) family involved in nitrate transport and assimilation in plants, which are essential for improving plant nitrogen use efficiency. Currently, the molecular nature and evolutionary trajectory of NLP genes in the C4 model crop foxtail millet are unknown. Therefore, we performed a comprehensive analysis of NLP and molecular evolution in foxtail millet by scanning the genomes of foxtail millet and representative species of the plant kingdom. We identified seven NLP genes in the foxtail millet genome, all of which are individually and separately distributed on different chromosomes. They were not structurally identical to each other and were mainly expressed on root tissues. We unearthed two key genes (Si5G004100.1 and Si6G248300.1) with a variety of excellent characteristics. Regarding its molecular evolution, we found that NLP genes in Gramineae mainly underwent dispersed duplication, but maize NLP genes were mainly generated via WGD events. Other factors such as base mutations and natural selection have combined to promote the evolution of NLP genes. Intriguingly, the family in plants showed a gradual expansion during evolution with more duplications than losses, contrary to most gene families. In conclusion, this study advances the use of NLP genetic resources and the understanding of molecular evolution in cereals.

Research on non-destructive and rapid detection technology of foxtail millet moisture content based on capacitance method and Logistic-SSA-ELM modelling.

Moisture content testing of agricultural products is critical for quality control, processing efficiency and storage management. Testing foxtail millet moisture content ensures stable foxtail millet quality and helps farmers determine the best time to harvest. A differential capacitance moisture content detection device was designed based on STM32 and PCAP01 capacitance digital converter chip. The capacitance method combined with the back-propagation(BP) algorithm and the extreme learning machine(ELM) algorithm was chosen to construct an analytical model for foxtail millet moisture content, temperature, and volume duty cycle. This work performs capacitance measurements on foxtail millet with different moisture contents, temperatures, and proportions of the measured substance occupying the detection area (that is, the volumetric duty cycle). On this foundation, the sparrow search algorithm (SSA) is used to optimize the BP and ELM models. However, SSA may encounter problems such as falling into local optimization solutions due to the reduction of population diversity in the late iterations. As a consequence, Logistic algorithm is introduced to optimize SSA, making it more appropriate for solving specific problems. Upon comparative analysis, the model predicted using the Logistic-SSA-ELM algorithm was more accurate. The results indicate that the predicted values of prediction set coefficient of determination (RP), prediction set root mean square error (RMSEP) and prediction set ratio performance deviation (RPDP) were 0.7016, 3.7150 and 1.4035, respectively. This algorithm has excellent prediction performance and can be used as a model for detection of foxtail millet moisture content. In view of the important role of foxtail millet moisture content detection in acquisition and storage, it is particularly important to study a nondestructive and fast online real-time detection method. The designed capacitive sensor with differential structure has well stabilization and high accuracy, which can be further studied in depth and gradually move towards the general trend of agricultural development of smart agriculture and precision agriculture.

The importance of starch chain-length distribution for in vitro digestion of ungelatinized and retrograded foxtail millet starch.

The digestibility of ungelatinized, short-term retrograded and long-term retrograded starch from foxtail millet was investigated and correlated with starch chain length distributions (CLDs). Some variations in starch CLDs of different varieties were obtained. Huangjingu and Zhonggu 9 had higher average chain lengths of debranched starch and lower average chain length ratios of amylopectin and amylose than Dajinmiao and Jigu 168. Compared to ungelatinized starch, retrogradation significantly increased the estimated glycemic index (eGI), whereas significantly decreased the resistant starch (RS). In contrast, long-term retrograded starches have lower eGI (93.33-97.37) and higher RS (8.04-14.55%) than short-term retrograded starch. PCA and correlation analysis showed that amylopectin with higher amounts of long chains and longer long chains contributed to reduced digestibility in ungelatinized starch. Both amylose and amylopectin CLDs were important for the digestibility of retrograded starch. This study helps a better understanding of the interaction of starch CLDs and digestibility during retrogradation.

Polyphenols from Foxtail Millet Improve Non-Alcoholic Fatty Liver Disease by Regulating Intestinal Microbiome in Mice.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic hepatic manifestation of metabolic dysfunction for which effective interventions are lacking. The burden of NAFLD is increasing at an alarming rate. NAFLD is frequently associated with morbidities such as dyslipidemia, type 2 diabetes mellitus and obesity, etc. The current study explored the potential role of bound polyphenols from foxtail millet (BPIS) in treating mice with NAFLD induced by a high-fat diet (HFD). The results indicated the critical role of BPIS in treating NAFLD by effectively restoring the gut microbiota in C57BL/6 mice that received a high-fat diet (HFD) for 12 weeks. At the same time, 16S rRNA analysis demonstrated that BPIS remodeled the overall structure of the gut microbiota from fatty liver diseases towards that of normal counterparts, including ten phylum and twenty genus levels. Further study found that the expression of tight junction proteins was upregulated in the BPIS-treated group. This study provides new insights into the potential NAFLD protective effects induced by polyphenols of foxtail millet.

High Overexpression of SiAAP9 Leads to Growth Inhibition and Protein Ectopic Localization in Transgenic Arabidopsis.

Amino acid permeases (AAPs) transporters are crucial for the long-distance transport of amino acids in plants, from source to sink. While Arabidopsis and rice have been extensively studied, research on foxtail millet is limited. This study identified two transcripts of SiAAP9, both of which were induced by NO3- and showed similar expression patterns. The overexpression of SiAAP9L and SiAAP9S in Arabidopsis inhibited plant growth and seed size, although SiAAP9 was found to transport more amino acids into seeds. Furthermore, SiAAP9-OX transgenic Arabidopsis showed increased tolerance to high concentrations of glutamate (Glu) and histidine (His). The high overexpression level of SiAAP9 suggested its protein was not only located on the plasma membrane but potentially on other organelles, as well. Interestingly, sequence deletion reduced SiAAP9's sensitivity to Brefeldin A (BFA), and SiAAP9 had ectopic localization on the endoplasmic reticulum (ER). Protoplast amino acid uptake experiments indicated that SiAAP9 enhanced Glu transport into foxtail millet cells. Overall, the two transcripts of SiAAP9 have similar functions, but SiAAP9L shows a higher colocalization with BFA compartments compared to SiAAP9S. Our research identifies a potential candidate gene for enhancing the nutritional quality of foxtail millet through breeding.

Assembly and comparative analysis of the first complete mitochondrial genome of Setaria italica.

MAIN CONCLUSION: In this study, we assembled the first complete mitochondrial genome of Setaria italica and confirmed the multi-branched architecture. The foxtail millet (Setaria italica) holds significant agricultural importance, particularly in arid and semi-arid regions. It plays a pivotal role in diversifying dietary patterns and shaping planting strategies. Although the chloroplast genome of S. italica has been elucidated in recent studies, the complete mitochondrial genome remains largely unexplored. In this study, we employed PacBio HiFi sequencing platforms to sequence and assemble the complete mitochondrial genome. The mitochondrial genome spans a total length of 446,614 base pairs and harbors a comprehensive set of genetic elements, including 33 unique protein-coding genes (PCGs), encompassing 24 unique mitochondrial core genes and 9 variable genes, along with 20 transfer RNA (tRNA) genes and 3 ribosomal RNA (rRNA) genes. Our analysis of mitochondrial PCGs revealed a pronounced codon usage preference. For instance, the termination codon exhibits a marked preference for UAA, while alanine (Ala) exhibits a preference for GCU, and glutamine (Gln) favors CAA. Notably, the maximum Relative Synonymous Codon Usage (RSCU) values for cysteine (Cys) and phenylalanine (Phe) are both below 1.2, indicating a lack of strong codon usage preference for these amino acids. Phylogenetic analyses consistently place S. italica in close evolutionary proximity to Chrysopogon zizanioides, relative to other Panicoideae plants. Collinearity analysis showed that a total of 39 fragments were identified to display homology with both the mitochondrial and chloroplast genomes. A total of 417 potential RNA-editing sites were discovered across the 33 mitochondrial PCGs. Notably, all these editing events involved the conversion of cytosine (C) to uracil (U). Through the employment of PCR validation coupled with Sanger sequencing for the anticipated editing sites of these codons, RNA-editing events were conclusively identified at two specific loci: nad4L-2 and atp6-1030. The results of this study provide a pivotal foundation for advanced genomic breeding research in foxtail millet. Furthermore, they impart essential insights that will be instrumental for forthcoming investigations into the evolutionary and molecular dynamics of Panicoideae species.

Insights into the starch and proteins molecular structure changes of foxtail millet sourdough: Effect of fermentation from grains of cereal to pre-meal.

This study investigated the effects of foxtail millet sourdough fermentation time (0, 8, 16, and 24 h) on the protein structural properties, thermomechanical, fermentation, dynamic rheological, starch granules crystalline regions molecular mobility, and starch microstructural characteristics. The fermentation led to a significant increase in the concentration of free amino acids from protein hydrolysis. Fourier transform infrared spectroscopy (FTIR) revealed changes in protein secondary structure and the presence of functional groups of different bioactive compounds. The result of thermomechanical properties showed a significant increase in the stability (0.70-0.79 min) and anti-retrogradation ability (2.29-3.14 Nm) of lactic acid bacteria (LAB) sourdough compared to the control dough, showing a wider processing applicability with radar profiler index. In contrast, sourdoughs with lower tan δ values had higher elasticity and strength. Scanning electron microscopy showed that the surface of the starch appeared from smooth to uneven with patchy shapes and cavities, which declined the crystallinity from 34.00 % to 21.57 %, 23.64 %, 25.09 %, and 26.34 % respectively. Fermentation changed the To, Tp, Tc, and ΔH of the starch. The results of the study will have great potential for application in the whole grain sourdough industry.

Genome-wide identification and functional analysis of the SiCIN gene family in foxtail millet (Setaria italica L.).

Cell wall invertase (CIN) is a vital member of plant invertase (INV) and plays a key role in the breakdown of sucrose. This enzyme facilitates the hydrolysis of sucrose into glucose and fructose, which is crucial for various aspects of plant growth and development. However, the function of CIN genes in foxtail millet (Setaria italica) is less studied. In this research, we used the blast-p of NCBI and TBtools for bidirectional comparison, and a total of 13 CIN genes (named SiCINs) were identified from foxtail millet by using Arabidopsis and rice CIN sequences as reference sequences. The phylogenetic tree analysis revealed that the CIN genes can be categorized into three subfamilies: group 1, group 2, and group 3. Furthermore, upon conducting chromosomal localization analysis, it was observed that the 13 SiCINs were distributed unevenly across five chromosomes. Cis-acting elements of SiCIN genes can be classified into three categories: plant growth and development, stress response, and hormone response. The largest number of cis-acting elements were those related to light response (G-box) and the cis-acting elements related to seed-specific regulation (RY-element). qRT-PCR analysis further confirmed that the expression of SiCIN7 and SiCIN8 in the grain was higher than that in any other tissues. The overexpression of SiCIN7 in Arabidopsis improved the grain size and thousand-grain weight, suggesting that SiCIN7 could positively regulate grain development. Our findings will help to further understand the grain-filling mechanism of SiCIN and elucidate the biological mechanism underlying the grain development of SiCIN.

Effects of Lactobacillus plantarum fermentation on the structure, physicochemical properties, and digestibility of foxtail millet starches.

This study investigated the effects of Lactobacillus plantarum fermentation on the structural, physicochemical, and digestive properties of foxtail millet starches. The fermented starch granules formed a structure with honeycomb-like dents, uneven pores, and reduced particle size. As the fermentation time extended, the amylose content of waxy (0.88 %) and non-waxy (33.71 %) foxtail millet starches decreased to the minimum value at 24 h (0.59 % and 29.19 %, respectively), and then increased to 0.85 % and 31.87 % at 72 h, respectively. Both native and fermented foxtail millet starches exhibited an A-type crystal structure. Compared with native samples, the fermented samples performed enhanced proportion of short-branched chain, crystallinity, and short-range ordered degree. After fermentation for 24 h, the solubility, adsorption capacity, and pasting viscosity of foxtail millet starches improved, whereas the swelling power, pasting temperature, breakdown, setback, and degree of retrogradation reduced. Additionally, fermentation increased the transition temperatures, enthalpy, and digestibility. Overall, Lactobacillus plantarum fermentation is considered a competent choice to regulate the characteristics of foxtail millet starch.

Inhibitory Effects of Soluble Dietary Fiber from Foxtail Millet on Colorectal Cancer by the Restoration of Gut Microbiota.

Colorectal cancer (CRC) is a common malignant tumor that occurs in the colon. Gut microbiota is a complex ecosystem that plays an important role in the pathogenesis of CRC. Our previous studies showed that the soluble dietary fiber of foxtail millet (FMB-SDF) exhibited significant antitumor activity in vitro. The present study evaluated the anticancer potential of FMB-SDF in the azoxymethane (AOM)- and dextran sodium sulfate (DSS)-induced mouse CRC models. The results showed that FMB-SDF could significantly alleviate colon cancer symptoms in mice. Further, we found that FMB-SDF consumption significantly altered gut microbiota diversity and the overall structure and regulated the abundance of some microorganisms in CRC mice. Meanwhile, KEGG pathway enrichment showed that FMB-SDF can also alleviate the occurrence of colon cancer in mice by regulating certain cancer-related signaling pathways. In conclusion, our findings may provide a novel approach for the prevention and biotherapy of CRC.

Latitudinal adaptation and dispersal pathway of foxtail millet suggested by geographical distribution of transposable elements inserted in the SiPRR37 gene.

We investigated the variation and geographical distribution of the Pseudo-regulator response 37 (Setaria italica PRR37; SiPRR37) gene, which is involved in heading time (photoperiodism) in foxtail millet. An allele of the SiPRR37 gene, in which an approximately 4.9-kb transposable element (designated TE1) is inserted (a loss-of-function or reduction-of-function type), is distributed sporadically in East Asia and broadly in Southeast Asia and South Asia, implying that this gene is important in latitudinal adaptation. In addition, we found a new allele of SiPRR37 with an insertion of a 360-bp TE (TE2) at this locus and investigated the geographical distribution of this new type. This SiPRR37 allele with TE2 is distributed in Japan, Korea, Nepal, Iran and Turkey. Both TE1 and TE2 are useful markers for tracing foxtail millet dispersal pathways in Asia.

Alternative Splicing Plays a Crucial Role in the Salt Tolerance of Foxtail Millet.

Foxtail millet is an important cereal crop that is relatively sensitive to salt stress, with its yield significantly affected by such stress. Alternative splicing (AS) widely affects plant growth, development, and adaptability to stressful environments. Through RNA-seq analysis of foxtail millet under different salt treatment periods, 2078 AS events were identified, and analyses were conducted on differential gene (DEG), differential alternative splicing gene (DASG), and overlapping gene. To investigate the regulatory mechanism of AS in response to salt stress in foxtail millet, the foxtail millet AS genes SiCYP19, with two AS variants (SiCYP19-a and SiCYP19-b), were identified and cloned. Yeast overexpression experiments indicated that SiCYP19 may be linked to the response to salt stress. Subsequently, we conducted overexpression experiments of both alternative splicing variants in foxtail millet roots to validate them experimentally. The results showed that, under salt stress, both SiCYP19-a and SiCYP19-b jointly regulated the salt tolerance of foxtail millet. Specifically, overexpression of SiCYP19-b significantly increased the proline content and reduced the accumulation of reactive oxygen species (ROS) in foxtail millet, compared to that in SiCYP19-a. This shows that SiCYP19-b plays an important role in increasing the content of proline and promoting the clearance of ROS, thus improving the salt tolerance of foxtail millet.

Characterization of the active components and bioaccessibility of phenolics in differently colored foxtail millets.

Differently colored foxtail millet (Setaria italica) cultivars were compared regarding their amylose, B-complex vitamin, vitamin E, and phenolic compositions, as well as the bioaccessibility of their phenolics in simulated in vitro digestion. Dark-colored foxtail millets contained more thiamine, pyridoxine, and tocopherols, but less riboflavin, than light-colored ones. Phenolics were more abundant in dark-colored cultivars. Insoluble bound fractions accounted for 75%-83% of the total phenolics, with ferulic acid detected as the most plentiful compound. The major bioaccessible phenolic was free ferulic acid, with 100%-120% bioaccessibility, depending on cultivar, followed by p-coumaric acid and isoferulic acid (50%-80%). These relatively high bioaccessibilities were likely due to the release of soluble conjugated or insoluble bound phenolics during digestion. However, the contents of other free phenolics were largely decreased following in vitro digestion, resulting in low bioaccessibility, which also means that the release from the conjugated and bound fractions was poor.

Identification and Expression Analysis of the WOX Transcription Factor Family in Foxtail Millet (Setaria italica L.).

WUSCHEL-related homeobox (WOX) transcription factors are unique to plants and play pivotal roles in plant development and stress responses. In this investigation, we acquired protein sequences of foxtail millet WOX gene family members through homologous sequence alignment and a hidden Markov model (HMM) search. Utilizing conserved domain prediction, we identified 13 foxtail millet WOX genes, which were classified into ancient, intermediate, and modern clades. Multiple sequence alignment results revealed that all WOX proteins possess a homeodomain (HD). The SiWOX genes, clustered together in the phylogenetic tree, exhibited analogous protein spatial structures, gene structures, and conserved motifs. The foxtail millet WOX genes are distributed across 7 chromosomes, featuring 3 pairs of tandem repeats: SiWOX1 and SiWOX13, SiWOX4 and SiWOX5, and SiWOX11 and SiWOX12. Collinearity analysis demonstrated that WOX genes in foxtail millet exhibit the highest collinearity with green foxtail, followed by maize. The SiWOX genes primarily harbor two categories of cis-acting regulatory elements: Stress response and plant hormone response. Notably, prominent hormones triggering responses include methyl jasmonate, abscisic acid, gibberellin, auxin, and salicylic acid. Analysis of SiWOX expression patterns and hormone responses unveiled potential functional diversity among different SiWOX genes in foxtail millet. These findings lay a solid foundation for further elucidating the functions and evolution of SiWOX genes.