Search Results (80)

The R2R3-MYB family of transcription factors (TFs) plays a crucial role in cell specification and secondary metabolism regulation during plant development. In Arabidopsis, MS188, a typical R2R3-MYB protein, is essential for tapetal development and pollen wall formation. However, the nuclear localization sequence (NLS) responsible for directing MS188 into the nucleus has not been fully elucidated. In this study, the subcellular localization of the NLS-containing proteins was determined by GFP tagging in tobacco leaves, and three NLS regions within MS188 were identified: two located at the N-terminus of R2-MYB and one at the C-terminus of R3-MYB. We further narrowed the NLSs located at amino acids (AAs) 12–15, 18–22, and 96–107 via point mutation analysis. Combined with the cytoplasmic protein FBA6, these NLSs fusion proteins could localize in the nucleus. Importantly, the proteins with mutations in AAs 18–22 exhibited completely cytoplasmic signals, whereas other mutated sites partially abolished the nuclear signals. These findings suggest that the NLS at AAs 18–22 is sufficient for nuclear localization. To confirm the NLS functions in vivo, we constructed the vectors including the MS188 gene without the NLS sites, which failed to complement the male sterile phenotype of ms188. We also searched the highly conserved NLSs in other R2R3-MYB TFs and showed they are required for nuclear localization. Collectively, these findings revealed the specific NLS regions within R2R3-MYB transcription factors and highlighted their critical role for subcellular localization in plant developmental regulation. Full article

MYB transcription factors (TFs) represent one of the largest gene families in plants, and previous studies have demonstrated their involvement in regulating anthocyanin synthesis. Eggplant is an important anthocyanin-rich solanaceae vegetable crop. In this study, a total of 219 MYB gene-family members were identified using the complete and high-quality eggplant genome, comprising 105 1R-MYBs, 107 R2R3-MYBs, 5 3R-MYBs, and 2 4R-MYBs. Using phylogenetic analysis, we divided them into 33 subfamilies. Members of the SmeMYB gene family are unevenly distributed on 12 chromosomes, but are mainly concentrated at the upper and lower ends of the chromosomes. In addition, the expression levels of R2R3-MYBs in differently colored eggplant tissues (peel, calyx, stem, flower, and leaf) were investigated with RNA-seq (RNA sequencing). A total of 13 differentially expressed R2R3-MYB transcription factors related to the synthesis of anthocyanins in different eggplant tissues were screened out. SmeMYB110, SmeMYB175, and SmeMYB182 were also found to play significant roles in this process. Furthermore, 10 MYB TFs were identified as potential genes regulating anthocyanin synthesis in different tissues. The quantitative real-time PCR (qRT-PCR) analysis results showed that SmeMYB175 was regarded as the most likely key transcription factor regulating anthocyanin synthesis in calyx. These results not only deepen our understanding of the MYB gene family in eggplant but also lay a solid foundation for further research on the regulation of SmeR2R3-MYBs in anthocyanin synthesis across diverse eggplant tissues. Full article

Quinoa (Chenopodium quinoa) is an Andean allotetraploid pseudocereal crop with higher protein content and balanced amino acid composition in the seeds. Ammonium (NH₄⁺), a direct source of organic nitrogen assimilation, mainly transported by specific transmembrane ammonium transporters (AMTs), plays important roles in the development, yield, and quality of crops. Many AMTs and their functions have been identified in major crops; however, no systematic analyses of AMTs and their regulatory networks, which is important to increase the yield and protein accumulation in the seeds of quinoa, have been performed to date. In this study, the CqAMTs were identified, followed by the quantification of the gene expression, while the regulatory networks were predicted based on weighted gene co-expression network analysis (WGCNA), with the putative transcriptional factors (TFs) having binding sites on the promoters of CqAMTs, nitrate transporters (CqNRTs), and glutamine-synthases (CqGSs), as well as the putative TF expression being correlated with the phenotypes and activities of GSs, glutamate synthase (GOGAT), nitrite reductase (NiR), and nitrate reductase (NR) of quinoa roots. The results showed a total of 12 members of the CqAMT family with varying expressions in different organs and in the same organs at different developmental stages. Complementation expression analyses in the triple mep1/2/3 mutant of yeast showed that except for CqAMT2.2b, 11/12 CqAMTs restored the uptake of NH₄⁺ in the host yeast. CqAMT1.2a was found to mainly locate on the cell membrane, while TFs (e.g., CqNLPs, CqG2Ls, B3 TFs, CqbHLHs, CqZFs, CqMYBs, CqNF-YA/YB/YC, CqNACs, and CqWRKY) were predicted to be predominantly involved in the regulation, transportation, and assimilation of nitrogen. These results provide the functions of CqAMTs and their possible regulatory networks, which will lead to improved nitrogen use efficiency (NUE) in quinoa as well as other major crops. Full article

Salvia miltiorrhiza, the valuable traditional Chinese medicinal plant, has been used in clinics for thousands of years. The water-soluble salvianolic acid compounds are bioactive substances used in treating many diseases. Gibberellins (GAs) are growth-promoting phytohormones that regulate plant growth and development. Previous studies have demonstrated that GAs can promote salvianolic acid accumulation in S. miltiorrhiza; however, the underlying mechanism requires further investigation. Here, we identified a GA-induced R2R3MYB transcription factor (TF), SmMYB71, from a transcriptome library of GA-treated S. miltiorrhiza. SmMYB71 was highly expressed in the root of S. miltiorrhiza and localized to the nucleus. SmMYB71-knockout hairy roots showed higher salvianolic acid accumulation compared to wild lines. Overexpressing SmMYB71 in S. miltiorrhiza hairy roots significantly decreased the content of salvianolic acid by downregulating key salvianolic acid biosynthesis enzymes such as SmRAS and SmCYP98A14. The GCC box in the promoter of SmMYB71 can bind with SmERF115, suggesting that SmMYB71 is regulated by SmERF115 in salvianolic acid biosynthesis. These findings demonstrate a novel regulatory role of SmMYB71 in GA-mediated phenolic acid biosynthesis. With the development of CRISPR/Cas9-based genome editing technology, the SmMYB71 regulation mechanism of salvianolic acid biosynthesis provides a potential target gene for metabolic engineering to increase the quality of S. miltiorrhiza. Full article

Elevated levels of reactive oxygen species (ROS) are caused by ultraviolet B radiation (UV-B) stress. In response, plants strengthen their cell membranes, impeding photosynthesis. Additionally, UV-B stress initiates oxidative stress within the antioxidant defense system and alters secondary metabolism, particularly by increasing the quantity of UV-absorbing compounds such as flavonoids. The v-myb avian myeloblastosis viral oncogene homolog (MYB) transcription factor (TF) may participate in a plant’s response to UV-B damage through its regulation of flavonoid biosynthesis. In this study, we discovered that the photosynthetic activity of Rhododendron chrysanthum Pall. (R. chrysanthum) decreased when assessing parameters of chlorophyll (PSII) fluorescence parameters under UV-B stress. Concurrently, antioxidant system enzyme expression increased under UV-B exposure. A multi-omics data analysis revealed that acetylation at the K68 site of the RcTRP5 (telomeric repeat binding protein of Rhododendron chrysanthum Pall.) transcription factor was upregulated. This acetylation modification of RcTRP5 activates the antioxidant enzyme system, leading to elevated expression levels of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). Upregulation is also observed at the K95 site of the chalcone isomerase (CHI) enzyme and the K178 site of the anthocyanidin synthase (ANS) enzyme. We hypothesize that RcTRP5 influences acetylation modifications of CHI and ANS in flavonoid biosynthesis, thereby indirectly regulating flavonoid production. This study demonstrates that R. chrysanthum can be protected from UV-B stress by accumulating flavonoids. This could serve as a useful strategy for enhancing the plant’s flavonoid content and provide a valuable reference for research on the metabolic regulation mechanisms of other secondary substances. Full article

MYB-related transcription factors (TFs) subfamily is a subfamily of MYB TFs, which are mainly involved in plant secondary metabolism, growth and development, and stress response. To explore the function of MYB-related subfamily genes in Rosa chinensis, this study systematically analyzed characters of the MYB-related subfamily members in R. chinensis with bioinformatic analysis using the genomic data of R. chinensis and investigated their expression characteristics using quantitative real-time PCR (qRT-PCR). The results show that 100 MYB-related proteins were identified in R. chinensis. Proteins are mainly found in the nucleus. Chromosome localization revealed that all MYB-related genes are mapped to seven chromosomes and are distributed in clusters. Collinear analysis shows that 13 pairs of MYB-related genes had a collinear relationship, indicating R. chinensis may have evolved its MYB-related subfamily gene through fragment duplication. The analysis of motifs and conserved domains shows that Motif 3 is the most conserved motif. There are numerous ABA and MeJA response elements in MYB-related genes. ABA and MeJA treatments significantly shortened the vase life of R. chinensis, while the flower diameter on day 3 was the largest, suggesting that ABA and MeJA might induce MYB-related gene expression during cut flower senescence. The expression of MYB-related genes is tissue specific, most of which show the highest expression levels in petals. Notably, among six plant growth regulator treatments, ABA treatment significantly increased RcMYB002 expression in R. chinensis, suggesting that RcMYB002 may be a crucial gene for ABA response. This study provides a reference for further research on the function of MYB-related genes in R. chinensis. Full article

The MYB gene family, widely distributed across a variety of plants, plays a crucial role in the phenylpropane metabolic pathway. In this study, we identified 146 R2R3-MYB genes in the ‘NanGuo’ pear genome by screening its gene sequences. Phylogenetic analysis divided these genes into seven subfamilies, and we examined each for stability through analyses of conserved structural domains and motifs. In addition, differences in the expression levels between two varieties, the ‘NanGuo’ pear and its red bud sport variant ‘NanHong’ pear, were investigated using quantitative real-time PCR (qRT-PCR). The results revealed that the expression levels of 12 R2R3-MYB transcription factors (TFs) corresponded with the trends in anthocyanin content. Specifically, the expression trends of eight R2R3-MYB TFs positively correlated with anthocyanin accumulation, whereas four exhibited opposite trends, suggesting their negatively regulatory role in anthocyanin accumulation. This study not only enhances our understanding of the MYB gene family in the ‘NanGuo’ pear genome but also lays a solid foundation for future research into the functional roles of PuMYBs. Full article

Abiotic stresses such as nitrogen deficiency, drought, and salinity significantly impact coconut production, yet the molecular mechanisms underlying coconut’s response to these stresses are poorly understood. MYB proteins, a large and diverse family of transcription factors (TF), play crucial roles in plant responses to various abiotic stresses, but their genome-wide characterization and functional roles in coconut have not been comprehensively explored. This study identified 214 CnMYB genes (39 1R–MYB, 171 R2R3–MYB, 2 3R–MYB, and 2 4R–MYB) in the coconut genome. Phylogenetic analysis revealed that these genes are unevenly distributed across the 16 chromosomes, with conserved consensus sequences, motifs, and gene structures within the same subgroups. Synteny analysis indicated that segmental duplication primarily drove CnMYB evolution in coconut, with low nonsynonymous/synonymous ratios suggesting strong purifying selection. The gene ontology (GO) annotation of protein sequences provided insights into the biological functions of the CnMYB gene family. CnMYB47/70/83/119/186 and CnMYB2/45/85/158/195 were identified as homologous genes linked to nitrogen deficiency, drought, and salinity stress through BLAST, highlighting the key role of CnMYB genes in abiotic stress tolerance. Quantitative analysis of PCR showed 10 CnMYB genes in leaves and petioles and found that the expression of CnMYB45/47/70/83/85/119/186 was higher in 3-month-old than one-year-old coconut, whereas CnMYB2/158/195 was higher in one-year-old coconut. Moreover, the expression of CnMYB70, CnMYB2, and CnMYB2/158 was high under nitrogen deficiency, drought, and salinity stress, respectively. The predicted secondary and tertiary structures of three key CnMYB proteins involved in abiotic stress revealed distinct inter-proteomic features. The predicted interaction between CnMYB2/158 and Hsp70 supports its role in coconut’s drought and salinity stress responses. These results expand our understanding of the relationships between the evolution and function of MYB genes, and provide valuable insights into the MYB gene family’s role in abiotic stress in coconut. Full article

The light plays a key role in regulating anthocyanin biosynthesis in plants. However, the molecular basis of anthocyanin synthesis in grape skins irradiated at night with supplemental white light (W), red light (R), blue light (B), and blue light for 3 h, 6 h, 9 h, and 12 h (B3, B6, B9, and B12) is not known. In the present study, the total anthocyanin content in grape skins was significant under different light (DL) and blue-light time (DT) treatments, and the best result was obtained with B9. Analysis of RNA-seq data determined that the key genes in the anthocyanin synthesis pathway, PAL, CHS, DFR, GT, CFIP, VIT_14s0068g00920, VIT_06s0009g02860, and VIT_06s0004g08150, were significantly up-regulated under night-time supplemental light treatments, which led to the significant expression of the phenylpropanoid biosynthesis, phenylalanine metabolism, flavonoid biosynthesis, flavone and flavonol biosynthesis, and the anthocyanin biosynthesis pathway, which were significantly expressed, promoting the accumulation of anthocyanin. The B caused significant expression of PAL (VIT_08s0040g01710), CFIP (VIT_13s0067g03820, VIT_13s0067g02870) and DFR (VIT_18s0001g12800), which may be one of the reasons for the better effect of B compared to W anthocyanin enrichment in grape skins. The DT treatment resulted in significant expression of GT (VIT_11s0052g01600), Peroxidase, VIT_09s0018g01190, and VIT_11s0037g00570. In addition, many TFs such as bHLH, MYB, ERF, WRKY, C2H2, MYB-related, and NAC were found to be involved in the synthesis of anthocyanins under light regulation. These results provide new insights into plants’ nocturnal supplemental-light regulation of anthocyanin accumulation. Full article

The MYB transcription factors (TFs) have substantial functions in anthocyanin synthesis as well as being widely associated with plant responses to various adversities. In the present investigation, we found an unreported MYB TF from Solanum aculeatissimum (a wild relative of eggplant) and named it SaMYB113 in reference to its homologous gene. Bioinformatics analysis demonstrated that the open reading frame of SaMYB113 was 825 bp in length, encoding 275 amino acids, with a typical R2R3-MYB gene structure, and predicted subcellular localization in the nucleus. Analysis of the tissue-specific expression pattern through qRT-PCR showed that the SaMYB113 was expressed at a high level in young stems as well as leaves of S. aculeatissimum. Transgenic Arabidopsis and tobacco plants overexpressing SaMYB113 pertinent to the control of the 35S promoter exhibited a distinct purple color trait, suggesting a significant change in their anthocyanin content. Furthermore, we obtained three tobacco transgenic lines with significant differences in anthocyanin accumulation and analyzed the differences in anthocyanin content by LC-MS/MS. The findings demonstrated that overexpression of SaMYB113 caused tobacco to have considerably raised levels of several anthocyanin components, with the most significant increases in delphinidin-like anthocyanins and cyanidin-like anthocyanins. The qRT-PCR findings revealed significant differences in the expression levels of structural genes for anthocyanin synthesis among various transgenic lines. In summary, this study demonstrated that the SaMYB113 gene has a substantial impact on anthocyanin synthesis, and overexpression of the SaMYB113 gene leads to significant modifications to the expression levels of a variety of anthocyanin-synthesizing genes, which leads to complex changes in anthocyanin content and affects plant phenotypes. This present research offers the molecular foundation for the research of the mechanism of anthocyanin formation within plants, as well as providing some reference for the improvement of traits in solanum crops. Full article

MYB transcription factors (TFs) play vital roles in plant growth, development, and response to adversity. Although the MYB gene family has been studied in many plant species, there is still little known about the function of R2R3 MYB TFs in sweet potato in response to abiotic stresses. In this study, an R2R3 MYB gene, IbMYB330 was isolated from sweet potato (Ipomoea batatas). IbMYB330 was ectopically expressed in tobacco and the functional characterization was performed by overexpression in transgenic plants. The IbMYB330 protein has a 268 amino acid sequence and contains two highly conserved MYB domains. The molecular weight and isoelectric point of IbMYB330 are 29.24 kD and 9.12, respectively. The expression of IbMYB330 in sweet potato is tissue-specific, and levels in the root were significantly higher than that in the leaf and stem. It showed that the expression of IbMYB330 was strongly induced by PEG-6000, NaCl, and H₂O₂. Ectopic expression of IbMYB330 led to increased transcript levels of stress-related genes such as SOD, POD, APX, and P5CS. Moreover, compared to the wild-type (WT), transgenic tobacco overexpression of IbMYB330 enhanced the tolerance to drought and salt stress treatment as CAT activity, POD activity, proline content, and protein content in transgenic tobacco had increased, while MDA content had decreased. Taken together, our study demonstrated that IbMYB330 plays a role in enhancing the resistance of sweet potato to stresses. These findings lay the groundwork for future research on the R2R3-MYB genes of sweet potato and indicates that IbMYB330 may be a candidate gene for improving abiotic stress tolerance in crops. Full article

MYB transcription factors (TFs) have been shown to be important regulators of plant growth and development, and the R2R3−MYB family plays an important role in the regulation of plant primary and secondary metabolism, growth, and development. In this study, the PmMYB45 gene sequence was successfully cloned from Pinus massoniana, with an open reading frame of 1476 bp, encoding 491 amino acids. The results of subcellular localization and transcriptional self-activation showed that the gene was localized in the nucleus and was self-activating. qPCR showed that the highest expression of PmMYB45 was found in stems. PmMYB45 can promote lignin synthesis when overexpressed in tobacco. These results suggest that PmMYB45 promotes lignin synthesis by regulating the lignin biosynthesis pathway. These findings improve our understanding of the mechanism of lignin biosynthesis in P. massoniana and provide a basis for molecular breeding functions. It also provides insights into the role of the MYB transcription factor family in lignin accumulation. Full article

Anthocyanins are water-soluble flavonoid pigments that play a crucial role in plant growth and metabolism. They serve as attractants for animals by providing plants with red, blue, and purple pigments, facilitating pollination and seed dispersal. The fruits of solanaceous plants, tomato (Solanum lycopersicum) and eggplant (Solanum melongena), primarily accumulate anthocyanins in the fruit peels, while the ripe fruits of Atropa belladonna (Ab) have a dark purple flesh due to anthocyanin accumulation. In this study, an R2R3-MYB transcription factor (TF), AbMYB1, was identified through association analysis of gene expression and anthocyanin accumulation in different tissues of A. belladonna. Its role in regulating anthocyanin biosynthesis was investigated through gene overexpression and RNA interference (RNAi). Overexpression of AbMYB1 significantly enhanced the expression of anthocyanin biosynthesis genes, such as AbF3H, AbF3′5′H, AbDFR, AbANS, and Ab3GT, leading to increased anthocyanin production. Conversely, RNAi-mediated suppression of AbMYB1 resulted in decreased expression of most anthocyanin biosynthesis genes, as well as reduced anthocyanin contents in A. belladonna. Overall, AbMYB1 was identified as a fruit-expressed R2R3-MYB TF that positively regulated anthocyanin biosynthesis in A. belladonna. This study provides valuable insights into the regulation of anthocyanin biosynthesis in Solanaceae plants, laying the foundation for understanding anthocyanin accumulation especially in the whole fruits of solanaceous plants. Full article

MYBs constitute the second largest transcription factor (TF) superfamily in flowering plants with substantial structural and functional diversity, which have been brought into focus because they affect flower colors by regulating anthocyanin biosynthesis. Up to now, the genomic data of several Chrysanthemum species have been released, which provides us with abundant genomic resources for revealing the evolution of the MYB gene family in Chrysanthemum species. In the present study, comparative analyses of the MYB gene family in six representative species, including C. lavandulifolium, C. seticuspe, C. ×morifolium, Helianthus annuus, Lactuca sativa, and Arabidopsis thaliana, were performed. A total of 1104 MYBs, which were classified into four subfamilies and 35 lineages, were identified in the three Chrysanthemum species (C. lavandulifolium, C. seticuspe, and C. ×morifolium). We found that whole-genome duplication and tandem duplication are the main duplication mechanisms that drove the occurrence of duplicates in CmMYBs (particularly in the R2R3-MYB subfamily) during the evolution of the cultivated chrysanthemums. Sequence structure and selective pressure analyses of the MYB gene family revealed that some of R2R3-MYBs were subjected to positive selection, which are mostly located on the distal telomere segments of the chromosomes and contain motifs 7 and 8. In addition, the gene expression analysis of CmMYBs in different organs and at various capitulum developmental stages of C. ×morifolium indicated that CmMYBS2, CmMYB96, and CmMYB109 might be the negative regulators for anthocyanin biosynthesis. Our results provide the phylogenetic context for research on the genetic and functional evolution of the MYB gene family in Chrysanthemum species and deepen our understanding of the regulatory mechanism of MYB TFs on the flower color of C. ×morifolium. Full article

Chinese flowering cabbage is an important bolting stem vegetable widely grown in southern China, but severe losses caused by soft rot disease are very common in this crop. The MYB transcription factor (TF) family is the largest TF family in plants and plays diverse roles in response to stresses. However, the responses of MYB TFs to biotic stress in Chinese flowering cabbage have not been systematically studied. Herein, 255 R2R3-MYB genes were identified in the genome of Chinese flowering cabbage and classified into 29 subgroups based on phylogenetic comparisons with Arabidopsis thaliana. Gene duplication events involved 182 gene duplication pairs, and we found that two tandem duplication events involving R2R3-MYB genes in Chinese flowering cabbage may also affect gene family expansion. Transcriptome data analysis indicated that MYB TF genes are highly enriched in differentially expressed gene (DEG) sets. Combined with phylogenetic and transcriptome analysis, we identified 12 R2R3-MYB genes that potentially play a role in the response to soft rot stress. Our research provides a foundation for further research on the response of R2R3-MYB genes to soft rot stress in Chinese flowering cabbage. Full article