Background: In order to clarify the the molecular mechanism of anthocyanin accumulation in green and purple fruits of pepper using metabolomics and transcriptomics,to identify different anthocyanin metabolites,and to analyze the differentially expressed genes involved in anthocyanin biosynthesis.. Results: We analyzed the anthocyanin metabolome and transcriptome data of the fruits of 2 purple pepper and 1 green pepper. A total of 5 anthocyanin metabolites and 2224 differentially expressed genes were identified between the green and purple fruits of pepper. Among the 5 anthocyanin metabolites,delphin chloride was unique to purple pepper fruits,which is the mainly responsible for the purple fruit color of pepper. A total of 59 unigenes encoding 7 enzymes were identified as candidate genes involved in anthocyanin biosynthesis in pepper fruit. The six enzymes (PAL,C4H,CHI,DFR,ANS,UFGT) had higher expression levels except the F3H gene in purple compared with green fruits. In addition,seven transcription factors were also found in this study. These transcription factors may contribute to anthocyanin metabolite biosynthesis in the fruits of pepper. One of differentially expressed gene novel.2098 was founded. It was not annotated in NCBI. Though blast analysis we preliminarily considered that this gene related to MYB transcription factor and was involved in anthocyanin biosynthesis in pepper fruit. Conclusions: Overall, the results of this study provide useful information for understanding anthocyanin accumulation and the molecular mechanism of anthocyanin biosynthesis in peppers.

Background: Steamed wheat bread have previously been shown to induce comparatively high postprandial plasma glucose responses, on the contrary, buckwheat products induced lower postprandial plasma glucose. The present study was to assess the effects of micronutrient enriched bread wheat variety Jizi439 and buckwheat on postprandial plasma glucose in healthy and diabetic subjects comparing with buckwheat and other bread wheat varieties. Methods: Two experiments were conducted to study the effects of bread wheat variety Jizi439 on the postprandial plasma glucose levels of the randomly selected subjects. The first experiment involved three types of steamed bread with equivalent of 50 g available carbohydrate fed to 10 normal weight young healthy subjects. Two types of steamed bread were made from two purple-grain bread wheat varieties, Jizi439 and Chu20, respectively, and the third type was made from the mixture of different white grain wheat varieties. Plasma glucose levels of each subject were measured at 15, 30, 45, 60, 120 min after eating. Glucose was used as a reference, the total area under curve (AUC) and glycemic index (GI) was calculated for test meal. The second experiment was performed among ten type 2 diabetics who were served equivalent of 50 g available carbohydrate of steamed bread made from Jizi 439, the mixture of white grain bread wheat and buckwheat, respectively. The plasma glucose increment was determined two hours thereafter. Results: In the first experiment, consumption of the steamed bread made from Jizi439 resulted in the least increase in plasma glucose and the GI was significantly lower than that of Chu20 and the mixture. In the second experiment, the average of postprandial 2 h plasma glucose increment of Jizi439 was 2.46 mmol/L which was significantly lower than that of the mixture of white wheat but was not significantly different from buckwheat. Conclusions: The results indicated that consumption of Jizi439 steamed bread resulted in significantly lower plasma glucose in both healthy and diabetic subjects, compared with other types of test foods, except buckwheat bread. The steam bread made from Jizi439 would be an ideal food for preventing and treatment of diabetes.

Genetic dissection kernel weight-related traits is of great significance for improving wheat yield potential. As one of the three major yield components of wheat, thousand kernel weight (TKW) was mainly affected by grain length (GL) and grain width (GW). To uncover the key loci for these traits, we carried out a quantitative trait loci (QTL) analysis of an F₆ recombinant inbred lines (RILs) population derived from a cross of Henong 5290 (small grain) and 06Dn23 (big grain) with a 50 K single nucleotide polymorphism (SNP) array. A total of 17 stable and big effect QTL, including 5 for TKW, 8 for GL and 4 for GW, were detected on the chromosomes 1B, 2A, 2B, 2D, 4B, 5A, 6A and 6D, respectively. Among these, there were two co-located loci for three traits that were mapped on the chromosome 4BS and 6AL. The QTL on 6AL was the most stable locus and explained 15.4–24.8%, 4.1–8.8% and 15.7–24.4% of TKW, GW and GL variance, respectively. In addition, two more major QTL of GL were located on chromosome arm 2BL and 2DL, accounting for 9.7–17.8% and 13.6–19.8% of phenotypic variance, respectively. In this study, we found one novel co-located QTL associated with GL and TKW in 2DL, QGl.haaf-2DL.2/QTkw.haaf-2DL.2, which could explain 13.6–19.8% and 9.8–10.7% phenotypic variance, respectively. Genetic regions and linked markers of these stable QTL will help to further refine mapping of the corresponding loci and marker-assisted selection (MAS) breeding for wheat grain yield potential improvement.

To investigate the molecular mechanisms underlying ascorbic acid (AsA) accumulation in pepper fruits and to identify key genes involved in its biosynthesis, we performed integrated metabolomic and transcriptomic analyses on two pepper cultivars—T41 (sweet pepper) and 22-5 (chili pepper)—at three developmental stages, including young fruit, green ripe, and color change stages. The results show that AsA content in both cultivars was significantly higher at the green ripe stage than the young fruit stage, with T41 exhibiting significantly higher AsA levels than 22-5 at both the young fruit and green ripe stages. Transcriptomic analysis identified a total of 24,433 differentially expressed genes (DEGs). KEGG pathway enrichment analysis revealed that genes associated with AsA biosynthesis were mainly enriched in the “ascorbate and aldarate metabolism” pathway. Follow-up validation confirmed APX3 as the most likely candidate gene responsible for the difference in AsA content between the two pepper fruit types, with its expression pattern negatively correlating with AsA accumulation. This study unveils the molecular regulatory mechanisms underlying AsA biosynthesis and provides a theoretical foundation for breeding pepper cultivars with elevated AsA levels. This study provides valuable insights into the molecular regulation of AsA biosynthesis and lays a theoretical foundation for breeding high-AsA pepper varieties.

Yellow leaf phenotypes represent an important trait in pepper and enrich genetic germplasm resources. Previous studies have primarily examined leaf yellowing caused by defects in chlorophyll biosynthesis, whereas the functions of chlorophyll degradation-related genes remain less well characterized. In this study, a yellow leaf phenotype (NY) was identified. Transmission electron microscopy and RNA-seq showed that differentially expressed genes were concentrated in photosynthesis- and chlorophyll-related pathways. CaCLH1 was then demonstrated to promote chlorophyll degradation. Yeast one-hybrid analysis identified the CabHLH18-like gene as a direct interactor with the CaCLH1 promoter and as a positive regulator of CaCLH1 transcription. The CabHLH18-like gene was highly expressed in yellow leaf pepper. The CabHLH18-like gene was subsequently isolated and characterized, revealing nuclear localization and transcription factor activity. Functional analysis showed that silencing the CabHLH18-like gene increased chlorophyll content, whereas its overexpression reduced chlorophyll content. These findings indicate that CaCLH1 is a direct downstream target of the CabHLH18-like gene and contributes to CabHLH18-like-gene-mediated regulation of leaf yellowing in pepper. This study refines mechanistic understanding of leaf yellowing and provides a foundation for future research and breeding applications in pepper.