Genome-wide identification and expression pattern analysis of R2R3-MYB transcription factor gene family involved in puerarin biosynthesis and response to hormone in Pueraria lobata var. thomsonii

Metabolite differences and molecular mechanism between dehiscent and indehiscent capsule of mature sesame

The loss of sesame capsule seed prior to harvest poses a significant economical challenge in mechanized production. The metabolites involved in capsule closure are still unclear. Using comparative metabolome and transcriptome analysis, this work investigated the molecular regulation and enrichment pathways in two sesame types of indehiscent capsule WanZhi28 (ND) and dehiscent capsule WanZhi2 (WZ2). The findings demonstrated that genes and metabolites were significantly enriched in lignin synthesis-related pathways. Furthermore, data suggests that lipid and sugar metabolism may have an impact on capsule closure. Apart from its function in cell signaling, the latter may contribute to the glycosylation of lignin monomers, while the former may provide ATP for cellular microtubule movement. This work concurrently focused on a large number of differentially expressed transcription factors linked to the sesame capsule's anti-cleft mechanism, providing new evidence for the discovery and use of functional markers and genes for capsule dehiscence. The identification of key pathways and regulatory mechanisms offers valuable information for developing strategies to mitigate seed loss during harvest, ultimately contributing to more efficient and profitable sesame production.

Integrative Analyses of Metabolome and Transcriptome Reveal Regulatory Network of Puerarin Biosynthesis in Pueraria montana var. lobata

Kudzu, scientifically known as Pueraria montana var. lobata (Willd.) Maesen & S.M.Almeida ex Sanjappa & Predeep (P. lobata), is a perennial vine belonging to the family Leguminosae. Puerarin, a unique constituent and primary active ingredient of this genus, exhibits a broad spectrum of pharmacological activities. This study started with several practical questions: Why is the root the main medicinal part? Why is it not peeled for medicinal purposes? Why is the harvest period usually from December to February? Although the puerarin biosynthesis pathway has been investigated, the stage at which the 8-C glycosylation reaction occurs remains controversial. In this study, metabolomics and transcriptomics analyses were performed on P. lobata organs and tissues, including leaves, young stems, mature stems, tuberous cortices, and cortex-excised tubers of roots. Two modules containing genes associated with puerarin biosynthesis were identified by WGCNA. The final selection of important candidate UDP-glucosyltransferases (UGTs) that may be involved in the puerarin biosynthesis pathway included two 8-C-GTs, three 7-O-GTs, and key transcription factors. On this basis, the regulatory network of puerarin biosynthesis was constructed and laid the foundation for the cultivation of high-quality medicinal kudzu with high puerarin content.

Transcriptomics integrated with targeted metabolomics reveals endogenous hormone changes in tuberous root expansion of Pueraria

BACKGROUND

Pueraria is a widely cultivated medicinal and edible homologous plant in Asia, and its tuberous roots are commonly used in the food, nutraceutical, and pharmaceutical industries. "Gange No. 5" is a local variety of Pueraria montana var. thomsonii (Bentham) M.R. Almeida (PMT) in Jiangxi Province, China. After optimizing its cultivation technique, we shortened the cultivation cycle of this variety from two years to one year, suggesting that the regulatory mechanism of the endogenous hormone system during tuberous root expansion may have changed significantly. In this study, we focused on the molecular mechanisms of endogenous hormones in promoting tuberous root expansion during one-year cultivation of "Gange No. 5".

RESULTS

The mid-late expansion period (S4) is critical for the rapid swelling of "Gange No. 5" tuberous roots during annual cultivation. At S4, the number of cells increased dramatically and their volume enlarged rapidly in the tuberous roots, the fresh weight of a single root quickly increased, and the contents of multiple nutrients (total protein, total phenol, isoflavones) and medicinal components (puerarin, puerarin apigenin, and soy sapogenin) were at their peak values. We compared the transcriptomes and metabolomes of S1 (the pre-expansion period), S4, and S6 (the final expansion period), and screened 42 differentially accumulated hormone metabolites and 1,402 differentially expressed genes (DEGs) associated with hormone biosynthesis, metabolism, and signaling. Most Auxin, cytokinins (CKs), jasmonic acids (JAs), salicylic acid (SA), melatonin (MLT), and ethylene (ETH), reached their maximum levels at S1 and then gradually decreased; however, abscisic acid (ABA) appeared in S6, indicating that most of the endogenous hormones may play a key role in regulating the initiation of tuberous root expansion, while ABA mainly promotes tuberous root maturation. Notably, multiple key genes of the 'Tryptophan metabolism' pathway (ko00380) were significantly differentially expressed, and COBRA1, COBRA2, YUCCA10, IAA13, IAA16, IAA20, IAA27, VAN3, ACAA2, and ARF were also identified to be significantly correlated with the expansion of "Gange No. 5" tuberous roots.

CONCLUSIONS

Our study has revealed how endogenous hormone regulation affects the expansion of "Gange No. 5" tuberous roots. These findings offer a theoretical foundation for improving the yield of PMT tuberous roots.

Genome-Wide Identification of the bHLH Gene Family in Callerya speciosa Reveals Its Potential Role in the Regulation of Isoflavonoid Biosynthesis

Callerya speciosa (Champ. ex Benth.) Schot is a significant leguminous plant valued for its edible tuberous roots, which are a plentiful source of isoflavonoids. Basic helix-loop-helix (bHLH) transcription factors (TFs) have been reported to regulate secondary metabolism in plants, especially flavonoid biosynthesis. However, the bHLH genes in C. speciosa have not yet been reported, and their regulatory role in isoflavonoid biosynthesis remains unexplored. Here, 146 CsbHLH genes were identified in the C. speciosa genome, classifying them into 23 subfamilies based on the gene structures and phylogenetic relationships. All the CsbHLH proteins contained both motifs 1 and 2, whereas motif 8 was only distributed in subgroup III (d + e). Collinearity analysis demonstrated that fragmental replications are the primary driver of CsbHLH evolution, with the majority of duplicated CsbHLH gene pairs experiencing selective pressure. Nine candidate CsbHLH genes were found to play a potential role in regulating isoflavonoid biosynthesis through a combination of gene-to-metabolite correlation analysis and weighted gene co-expression network analysis (WGCNA). Additionally, the cis-regulatory elements and response to MeJA of these nine genes were characterized and confirmed through quantitative real-time PCR (qRT-PCR) analysis. Among them, three CsbHLHs (CsbHLH9, CsbHLH89, and CsbHLH95) were selected for further investigation. Yeast two-hybrid (Y2H), dual-luciferase (LUC) assays, bimolecular fluorescence complementation (BiFC) assays, and transient transformation demonstrated that CsbHLH9 acted as a transcriptional activator through its interaction with CsMYB36 and binding to the promoters of isoflavonoid biosynthesis genes in a MeJA-induced manner, such as CsIFR2, CsI3'H2, and CsCHS4, to promote isoflavonoid (calycosin, calycosin-7-o-glucoside, and formononetin) accumulation. Our results establish a basis for the functional analysis of bHLH genes and investigations into the molecular mechanisms underlying isoflavonoid biosynthesis in C. speciosa.

Integrated Metabolomic and Transcriptomic Analysis of Puerarin Biosynthesis in Pueraria montana var. thomsonii at Different Growth Stages

Puerarin, a class of isoflavonoid compounds concentrated in the roots of Puerarias, has antipyretic, sedative, and coronary blood-flow-increasing properties. Although the biosynthetic pathways of puerarin have been investigated by previous researchers, studies focusing on the influence of different growth stages on the accumulation of metabolites in the puerarin pathway are not detailed, and it is still controversial at the last step of the 8-C-glycosylation reaction. In this study, we conducted a comprehensive analysis of the metabolomic and transcriptomic changes in Pueraria montana var. thomsonii during two growing years, focusing on the vigorous growth and dormant stages, to elucidate the underlying mechanisms governing the changes in metabolite and gene expression within the puerarin biosynthesis pathway. In a comparison of the two growth stages in the two groups, puerarin and daidzin, the main downstream metabolites in the puerarin biosynthesis pathway, were found to accumulate mainly during the vigorous growth stage. We also identified 67 common differentially expressed genes in this pathway based on gene expression differences at different growth stages. Furthermore, we identified four candidate 8-C-GT genes that potentially contribute to the conversion of daidzein into puerarin and eight candidate 7-O-GT genes that may be involved in the conversion of daidzein into daidzin. A co-expression network analysis of important UGTs and HIDs along with daidzein and puerarin was conducted. Overall, our study contributes to the knowledge of puerarin biosynthesis and offers information about the stage at which the 8-C-glycosylation reaction occurs in biosynthesis. These findings provide valuable insights into the cultivation and quality enhancement of Pueraria montana var. thomsonii.

Genome-Wide Identification and Analysis of R2R3-MYB Genes Response to Saline-Alkali Stress in Quinoa

Soil saline-alkalization inhibits plant growth and development and seriously affects crop yields. Over their long-term evolution, plants have formed complex stress response systems to maintain species continuity. R2R3-MYB transcription factors are one of the largest transcription factor families in plants, widely involved in plant growth and development, metabolism, and stress response. Quinoa (Chenopodium quinoa Willd.), as a crop with high nutritional value, is tolerant to various biotic and abiotic stress. In this study, we identified 65 R2R3-MYB genes in quinoa, which are divided into 26 subfamilies. In addition, we analyzed the evolutionary relationships, protein physicochemical properties, conserved domains and motifs, gene structure, and cis-regulatory elements of CqR2R3-MYB family members. To investigate the roles of CqR2R3-MYB transcription factors in abiotic stress response, we performed transcriptome analysis to figure out the expression file of CqR2R3-MYB genes under saline-alkali stress. The results indicate that the expression of the six CqMYB2R genes was altered significantly in quinoa leaves that had undergone saline-alkali stress. Subcellular localization and transcriptional activation activity analysis revealed that CqMYB2R09, CqMYB2R16, CqMYB2R25, and CqMYB2R62, whose Arabidopsis homologues are involved in salt stress response, are localized in the nucleus and exhibit transcriptional activation activity. Our study provides basic information and effective clues for further functional investigation of CqR2R3-MYB transcription factors in quinoa.