Search Results (340)

Secondary cell wall (SCW) formation and lignin biosynthesis are critical biological processes that determine wood properties. Masson pine (Pinus massoniana Lamb) is a fast-growing conifer species with significant economic value for the pulp and paper industry. While R2R3-MYB transcription factors are known as master regulators of SCW biosynthesis, the specific R2R3-MYB members regulating lignin formation in Masson pine remain largely uncharacterized. In this study, we identified 317 R2R3-MYB genes in the Masson pine genome. Phylogenetic analysis revealed that PmMYB289, a member of the P20 subgroup, is highly homologous to the Arabidopsis SCW regulators AtMYB52 and AtMYB54. Expression profiling demonstrated that PmMYB289 is predominantly expressed in highly lignified old stems. Transcriptional activation assays confirmed that PmMYB289 lacks autoactivation activity. Subcellular localization analysis revealed that PmMYB289 was localized to the nucleus. Ectopic overexpression of PmMYB289 in tobacco (Nicotiana benthamiana) resulted in dwarfed plant growth, reduced stem diameter, and curled leaves. Molecular analysis of these transgenic lines showed a significant downregulation of most key SCW biosynthetic genes, with the exception of NbPAL1. These findings indicate that PmMYB289 acts as a crucial transcriptional repressor in SCW biosynthesis, providing valuable genetic resources for the molecular breeding of superior Masson pine varieties. Full article

To develop safe and effective preservatives for fresh-cut produce, this study elucidates the multi-pathway mechanisms through which Melatonin (MT) regulates postharvest senescence in fresh-cut potatoes. Treatment with 0.1 mmol/L exogenous MT effectively inhibited browning and softening during storage. In terms of browning control, MT suppressed PPO and POD activities by 46% and ~10% at the end of storage (day 12), while enhancing enzymatic and non-enzymatic antioxidant capacity by 1.1- to 1.6-fold on average throughout storage. This alleviated oxidative damage and membrane lipid peroxidation, thereby reducing tissue browning. Regarding texture maintenance, MT downregulated PME and cellulase activities by 23% and 19% at the end of storage, activated phenylpropanoid metabolism, and inhibited starch degradation (maintaining 19% higher starch content), thus preserving cell wall structure and firmness (9.2% higher at the end of storage). Further analysis revealed that MT antagonized ethylene biosynthesis, upregulated StMYB168 expression (5.8-fold higher than control on average), and activated endogenous MT biosynthesis, establishing a self-sustaining positive regulatory cycle. Correlation analysis confirmed close relationships among physiological processes, signaling responses, and quality traits, with significant associations between firmness and starch content (r = 0.72), color indices and PPO/POD (|r| > 0.65), and MT biosynthesis genes and metabolic pathways (r = 0.65–0.75) (p < 0.01). Full article

Phosphorus (P) deficiency severely limits the growth and yield of crop plants, and anthocyanin accumulation is a key adaptive physiological response to low-P stress. However, the role of MYB transcription factors in regulating anthocyanin biosynthesis under P-deficient conditions and the application of favorable haplotypes in foxtail millet low-P tolerance breeding remain unclear. Here, we performed genome-wide identification of SiMYB genes, elucidated their evolutionary characteristics, and identified key members regulating anthocyanin accumulation under P deficiency to provide genetic resources and a theoretical basis for foxtail millet molecular breeding aimed at improving nutrient use efficiency. Specifically, a total of 229 SiMYB genes were identified in the foxtail millet genome and classified into three subgroups, with the R2R3-MYB subfamily accounting for 59.8%. Phylogenetic and synteny analyses across 15 plant species revealed diverse divergence times and complex relationships, with 29 R2R3-MYB genes showing conserved collinearity with rice and maize orthologs. Association analysis using 196 foxtail millet accessions showed that 38 single nucleotide polymorphisms (SNPs) from 16 SiMYB genes were significantly associated with leaf anthocyanin content under P deficiency (p < 0.001). Notably, the SiMYB169 gene exhibited differential tissue expression and was highly upregulated in the leaves of a P-tolerant genotype after 24 h of P deficiency treatment. Furthermore, accessions carrying the favorable G allele of SiMYB169 showed significantly higher anthocyanin accumulation under P deficiency (p < 0.01). Network prediction analysis found that SiMYB169 interacted with key genes and multiple transcription factors in the biosynthesis pathway of anthocyanin. These findings highlight SiMYB169 as an evolutionarily conserved regulator that modulated anthocyanin biosynthesis under P-deficient conditions. Full article

Aquilegia oxysepala is a characteristic wildflower of Northeast China, which has great application potential owing to its unique floral morphology and strong adaptability. The R2R3-MYB is one of the largest transcription factor families and has important roles in anthocyanin biosynthesis. A total of 90 AoMYBs were identified from A. oxysepala and divided into 29 subfamilies via phylogenetic analysis. Using bioinformatics methods, a systematic analysis was conducted on the physicochemical properties, gene structures, conserved motifs, and other characteristics of these genes. Based on the transcriptomic data of A. oxysepala and A. oxysepala f. pallidiflora across different floral developmental stages, 32 differentially expressed genes (DEGs) belonging to the R2R3-MYB family were screened, and their expression patterns were analyzed. The results indicated that AoMYB32 and AoMYB34 were significantly upregulated only at the pre-anthesis stage (PrA) in A. oxysepala, whereas their expression levels remained relatively low in A. oxysepala f. pallidiflora during the same stage. Correlation network analysis indicated that AoMYB34 was positively correlated with six functional genes associated with anthocyanin synthesis, namely PAL-2, C4H, 4CL, CHS, F3′5′H, and ANS. Reverse transcription quantitative PCR (RT-qPCR) validation revealed that AoMYB32 and AoMYB34 exhibited significant upregulation at the PrA stage in A. oxysepala, while their expression showed no obvious fluctuations across the entire flowering period in A. oxysepala f. pallidiflora. In summary, it is postulated that AoMYB32 and AoMYB34 are candidate genes associated with flower color variation formation of A. oxysepala. This study provides a theoretical basis and genetic resources for deciphering the mechanism of flower color formation and facilitating flower color improvement breeding in A. oxysepala. Full article

Zinc finger proteins (ZFPs) are a diverse group of plant transcription factors essential for regulating development, signaling, and stress responses. In this study, we performed a genome-wide identification and integrative analysis of 140 C3H-type zinc finger transcription factor genes in the soybean genome, exhibiting an uneven distribution across all 20 chromosomes. These C3H-ZFPs contained one (37), two (58), three (19), four (7), five (17), or six (2) C3H domains and were classified into 14 subsets based on their domain architecture. All C3H genes encoding proteins harbored the conserved C3H-ZFP domain and displayed various physicochemical characteristics. Phylogenetic analysis grouped them into 10 clades, closely related to other species like Arabidopsis, rice and alfalfa. Promoter analysis revealed cis-elements associated with stress response (~39.1%), light response (~37.3%), phytohormones (~18.5%), and development (~4.97%). Duplication analysis revealed 78 pairs of segmental and eight tandem duplication events, with purifying selection indicated by Ka/Ks (nonsynonymous/synonymous) ratios, indicating that these C3H-ZFP duplicates were largely maintained under purifying selection. A total of 388 miRNAs from 196 gene families were predicted to target 140 C3H-ZFP genes, with most enriched miRNAs targeting C3H-ZFP genes, including the miR156, miR395, and miR396 families. Transcription factor binding sites for MYB, AP2, MIKC_MADS, BBR-BPC, ERF, C2H2, and Dof were found upstream of most C3H-ZFP genes. RNA-Seq and qRT-PCR analyses showed tissue-specific expression and stress-responsive expression patterns, with several C3H-ZFP genes, especially GmC3H1, GmC3H63, GmC3H124, and GmC3H127, being significantly upregulated under abiotic stress conditions. Together, these results provide a comprehensive overview of soybean C3H-ZFP genes and identify promising candidates for future functional studies on development and abiotic stress adaptation. Full article

Low-temperature stress is a major factor limiting the development of the chrysanthemum industry. Chrysanthemum indicum L., wild germplasm with strong cold tolerance within the genus, is an ideal material for mining cold resistance genes. Through preliminary transcriptome analysis of C. indicum under low-temperature stress (PRJNA1391062), we found that multiple R2R3-MYB family members were significantly differentially expressed (|log₂FC| ≥ 1, p < 0.05), suggesting that this family may play important roles in cold stress responses. Within the C. indicum genome, we identified 63 R2R3-MYB members (CiMYBs) through HMMER and BLAST searches combined with domain validation. Phylogenetic analysis classified these genes into 19 subgroups, with most key nodes supported by bootstrap values > 80%. Promoter cis-element analysis revealed enrichment of elements related to light responsiveness, hormone signaling, and stress responses, including 41 low-temperature responsive elements distributed across 28 genes and 32 drought-induced MYB-binding sites present in 23 genes. Synteny analysis identified 13 duplicated gene pairs within the C. indicum genome and 41 collinear gene pairs between C. indicum and Arabidopsis thaliana L. Transcriptome data under low-temperature stress showed that 22 of the 63 CiMYB members were differentially expressed under 4 °C acclimation and −4 °C freezing stress, and they could be classified into three response patterns: acute stress-responsive (rapid upregulation upon initial stress), acclimation-induced (significant activation after 4 °C acclimation), and freezing-suppressed (downregulation after −4 °C freezing). Six differentially expressed genes were randomly selected for RT-qPCR validation, and the results showed consistent trends with the transcriptome data. This study provides a comprehensive identification of R2R3-MYB family members in C. indicum and reveals their expression divergence under low-temperature stress, offering candidate gene resources for deciphering the cold adaptation mechanisms of C. indicum and breeding new cold-resistant chrysanthemum cultivars. Full article

R2R3-MYB and bHLH transcription factors (TFs) are key regulators of floral secondary metabolism and epidermal development in flowering plants. Orchids exhibit remarkable floral diversity, which is critical for pollination success and ornamental value, yet the evolutionary and functional diversification of these TF families within the genus remains largely unexplored. Here, we conducted a comprehensive pan-genome dissection of R2R3-MYB and bHLH TF families across 18 Dendrobium species, integrating orthologs assignment, phylogenetics, duplication profiling, cis-regulatory annotation, and tissue-specific expression analysis. We identified 3074 R2R3-MYB and 2282 bHLH genes, classified into 69 and 61 orthologous gene groups (OGGs), respectively. Core OGGs accounted for two-thirds of both families, indicating strong evolutionary conservation, whereas variable OGGs reflected lineage-specific diversification. Phylogenetic analyses resolved R2R3-MYBs into 24 canonical subfamilies and revealed conserved heterogeneous expansion patterns in bHLH subfamilies. Promoter architectures of R2R3-MYB genes were enriched in hormone-, stress-, and light-responsive elements, whereas bHLH promoters were dominated by development-related motifs. Tissue-specific expression profiling in Dendrobium ‘Chao Praya Smile’ showed that floral bud-enriched genes were associated with flavonoid/anthocyanin biosynthesis, whereas root-enriched genes were linked to stress and hormone responses. Integration of pan-genomics and transcriptomics highlighted evolutionary trajectory and functional divergence between core and variable gene sets within Dendrobium. Our study establishes a comprehensive, genus-wide framework for understanding the evolutionary and functional characteristics of MYB–bHLH regulatory networks in Dendrobium. These findings provide valuable genetic resources and key candidate targets for functional characterization and molecular breeding, with important implications for genetic improvement of reproductive traits, floral quality, stress resistance, and ornamental and agronomic value in orchids. Full article

MYB transcription factors (TFs) are crucial for plant growth, development, and response to abiotic stress. However, their exact functions in abiotic stress responses in rapeseed remain largely unexplored. In this study, we identified and characterized BnaMYB73, a member of the R2R3-MYB subfamily, and investigated its role in abiotic stress tolerance. The transcription level of BnaMYB73 was significantly upregulated in response to salt and osmotic stress. Transgenic Arabidopsis thaliana lines expressing BnaMYB73 displayed significantly enhanced tolerance to salt and osmotic stress, while showing no phenotypic differences in growth compared with wild-type (WT) plants under normal conditions. Physiological analyses revealed that the BnaMYB73-expressing plants accumulated higher proline levels, exhibited elevated superoxide dismutase (SOD) and peroxidase (POD) activities, and reduced malondialdehyde (MDA) content under stress conditions. Moreover, the BnaMYB73-expressing plants significantly upregulated key stress-responsive genes, including AtRD29B, AtDREB2A, AtRAB18, AtP5CS1, AtSOS1 and AtCAT1. Collectively, these findings establish BnaMYB73 functions as a stress-responsive transcription factor that enhances abiotic stress tolerance and provide a promising target for breeding stress-resilient rapeseed cultivars. Full article

Longan (Dimocarpus longan Lour.) is highly sensitive to low temperature, which severely restricts its cultivation and industrial development. MYB transcription factors serve as key regulators in plant responses to cold stress. In this study, an R2R3-MYB gene DlMYB108 was cloned from ‘Shixia’ longan. Sequence analysis showed that DlMYB108 contains two typical MYB repeats and shares high homology with cold-responsive MYB108 proteins from other plants. Expression pattern analysis revealed that DlMYB108 is highly expressed in young leaves, which are more sensitive to cold stress, and is significantly induced by low-temperature treatment. Subcellular localization and transcriptional activation assays confirmed that DlMYB108 is a nuclear-localized transcriptional activator. Yeast one-hybrid and dual-luciferase assays demonstrated that DlMYB108 specifically binds to the promoters of DlCBF2 and DlCBF3 and activates their transcription. Heterologous expression of DlMYB108 in Arabidopsis significantly enhanced cold tolerance, accompanied by reduced ion leakage, malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation, as well as upregulated expression of CBF and cold-responsive genes. Collectively, DlMYB108 positively regulates longan cold tolerance through activating DlCBF2 and DlCBF3 expression, providing a valuable candidate gene for cold-tolerant longan breeding. Full article

Cibotium barometz (L.) J. Sm., a medicinally significant fern in traditional Chinese medicine, is little explored at the genomic level regarding its bioactive compounds. Using an integrated approach combining Illumina and PacBio sequencing technologies, we profiled its root, rachis, and pinna transcriptomes, identifying 12,718, 21,341, and 11,441 unigenes, respectively. Our analysis systematically characterized the transcriptional features of transcription factors (TFs), simple sequence repeats (SSRs), long non-coding RNAs (lncRNAs), and differentially expressed genes (DEGs). Enrichment analyses highlighted the roles of highly expressed unigenes in secondary metabolism. Seventeen key enzymes involved in polysaccharide biosynthesis showed tissue-specific expression patterns. Notably, total polysaccharide content correlated positively with UDP-arabinose 4-epimerase (UXE) expression but negatively with phosphoglucomutase (PGM) and 3,5-epimerase/4-reductase (UER1). Flavonoid accumulation inversely correlated with chalcone synthase (CHS) expression. Two lignin pathways (H-lignin and G-lignin) were characterized, with phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) as key genes. The absence of ferulate-5-hydroxylase (F5H) explains the undetected S-lignin pathway. Regulatory network analysis revealed positive correlations between PAL expression and NAC72/NAC78/WRKY35 and C4H expression and WRKY65/WRKY69/WRKY71, while a negative correlation was revealed between flavonoid 3′,5′-hydroxylase (F3′5′H) and MYB3R4. This study provides comprehensive transcriptomic insights into C. barometz bioactive compound biosynthesis, serving as a foundation for mechanistic research. Full article

Kiwiberry (Actinidia arguta) has been rapidly commercialized. However, fruits produced in northern growing regions predominantly have green peels, and the red/purple peel phenotypes remain relatively rare, which limits the discovery and utilization of red-peel germplasm. Peel reddening is primarily caused by the accumulation of anthocyanins, and R2R3-MYB transcription factors are key regulators of the flavonoid/anthocyanin biosynthetic pathway. However, the MYB transcription factor family in the genus Actinidia has been less studied, with few systematic analyses linked to color phenotypes. Therefore, we performed a genome-wide search for R2R3-MYB family members in A. arguta and characterized their physicochemical properties, phylogeny, chromosomal distribution, gene duplication events, and synteny relationships. Furthermore, RNA-Seq analysis, phylogenetic analysis, and gene expression patterns of the rare northern red-peel cultivar ‘Yanlong 1’ revealed that AaMYB1 and AaMYB36 are key candidate genes closely associated with anthocyanin biosynthesis in the fruit peel. Validation experiments revealed that both genes exhibited significantly higher expression during the coloration stage than during the green fruit stage, as well as significantly higher expression in the red-peel cultivar than in green-peel cultivars. Four key structural genes (UFGT, CHS, DFR, and ANS), especially, CHS, DFR, and ANS, displayed a similar pattern of upregulation. These correlative results suggest that AaMYB1 and AaMYB36 are candidate positive regulators of peel-specific anthocyanin accumulation. These results provide important targets for developing molecular markers and improving the red-peel trait in northern A. arguta through breeding. Full article

Drought stress significantly limits crop yield by disturbing plant water status and redox homeostasis, leading to oxidative stress and growth suppression. Anthocyanins, with their strong antioxidant properties, are closely linked to abiotic stress adaptation. The R2R3-MYB transcription factor SlANT1 promotes anthocyanin biosynthesis in tomato, yet its role in drought resistance remains poorly understood. This study explored the function of SlANT1 in tomato under drought conditions. SlANT1 expression was upregulated under both drought and high salinity. The overexpression of SlANT1 resulted in higher anthocyanin accumulation and reduced leaf and stem dimensions. Under drought, SlANT1-overexpression (SlANT1-OE) plants maintained a greater leaf relative water content, showed less negative water potential, wilted less, and recovered faster after rewatering. These plants also accumulated lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). While antioxidant enzyme activities were generally reduced, anthocyanin-dependent ROS scavenging was significantly enhanced. SlANT1 overexpression also modulated carbohydrate metabolism and aquaporin gene expression, elevating sucrose, fructose, glucose, and soluble protein while decreasing starch, thereby supporting osmotic adjustment. Notably, while stomata remained partially open in SlANT1-OE plants during drought, they exhibited reduced stomatal density, which likely compensated for the wider apertures and helped maintain favorable water status, while still sustaining higher photosynthetic rates and photosystem II integrity. These findings demonstrate that SlANT1 enhances drought tolerance through coordinated mechanisms involving anthocyanin-mediated antioxidant protection, improved water relations, and the reprogramming of carbohydrate and aquaporin pathways. SlANT1 thus represents a promising target for breeding drought-resilient, high-anthocyanin tomato varieties. Full article

Drought stress induces pronounced metabolic and transcriptional reprogramming of glucosinolate (GLS) biosynthesis in Brassica oleracea. An integrative approach combining HPLC-based quantification of individual GLSs, quantitative real-time PCR of core biosynthetic and regulatory genes, correlation-based network analysis, and in silico promoter characterization was applied to evaluate drought responses across genetically diverse accessions. Drought triggered strong, accession-specific shifts in GLS composition, with sinigrin content increasing from 35.9% to 55.1% in BR1 and glucoerucin reaching up to 80.2% in CCP1, while indolic GLSs such as glucobrassicin and neoglucobrassicin accounted for >75% of total GLSs in CV2 and CCP3. Hierarchical clustering separated accessions into four distinct drought response clusters independent of morphotype. Correlation analysis revealed drought-induced rewiring of GLS interdependencies, characterized by strengthened positive associations among aliphatic GLSs (r > 0.75). Gene expression profiling identified conserved MYB-centered regulatory modules (MYB28, MYB29, MYB34, MYB122) alongside strong accession-specific induction of CYP79F1 (up to 6.3-fold), FMOGS-OX5 (up to 4.8-fold), and ST5a (up to 5.1-fold). Promoter analysis revealed enrichment of ABA- and stress-responsive cis-regulatory elements. These findings delineate a genotype-dependent regulatory framework underlying GLS plasticity and identify quantitative metabolic and transcriptional markers relevant for breeding drought-resilient Brassica cultivars. Full article

Powdery mildew (PM) is a major disease affecting bitter gourd cultivation, and resolving the molecular regulatory mechanisms underlying PM resistance is important for bitter gourd molecular breeding for resistance. In this study, morphological and molecular methods were used to identify the PM pathogen in bitter gourd, and comparative transcriptome analysis was performed on leaves of the resistant cultivar R and the susceptible cultivar S after PM infection. The morphological and molecular identification results showed that the PM pathogen in bitter gourd was Podosphaera xanthii. Scanning electron microscopy results revealed that the P. xanthii exhibited distinct growth patterns in the R and S after P. xanthii infection. Compared to the S, the R exhibited 3966, 2729, 5891, and 3878 differentially expressed genes (DEGs) at 0, 2, 3, and 4 days after P. xanthii infection, respectively. KEGG enrichment analysis showed that DEGs were primarily enriched in plant–pathogen interactions, MAPK signaling pathway plants, and plant hormone signal transduction pathways. Transcription factor (TF) analysis of differentially expressed genes revealed that MYB, bHLH, and ERF family members could be involved in the defense process against the P. xanthii infection. Moreover, the analysis of the MLO genes revealed that Moc10g30350.1 could be involved in regulating PM resistance. These findings could enrich the molecular theoretical basis for resistance to PM, and provide new insights for the molecular breeding process of bitter gourd resistance to PM. Full article

Seed coat color in peanut (Arachis hypogaea L.) is a critical agronomic trait that affects both nutritional quality and market appeal. In this study, we identified two bHLH transcription factor genes, AhWSC1a and AhWSC1b, homologues of Arabidopsis TRANSPARENT TESTA 8, as indispensable gatekeepers of basal flavonoid pigmentation. QTL-seq analysis of a recombinant inbred line population derived from a black-testa parent (S3) and a white-testa parent (S2) revealed that recessive loss-of-function mutations in both AhWSC1a/1b abolish proanthocyanidin biosynthesis, resulting in a white testa. Integrated metabolomic and transcriptomic profiling confirmed the absence of proanthocyanidins and a strong repression of late anthocyanin-pathway genes (DFR, LDOX) in the mutants. Molecular assays further demonstrated that AhWSC1 physically interacts with the R2R3-MYB regulator AhTc1 to form a functional MBW complex that activates AhDFR and AhLDOX transcription. In this research, we also found that the black testa phenotype may arise from elevated AhTc1 expression associated with a structural variant (SV); however, in the SV background, the introduction of ahwsc1a/1b mutant leads to a significant suppression of AhTc1 expression. Notably, because AhWSC1 is transcriptionally silent in hairy-root systems, overexpression of AhTc1 alone failed to induce these late-stage anthocyanin biosynthesis genes, highlighting AhWSC1 as an indispensable, rate-limiting hub of anthocyanin biosynthesis pathway regulation. Collectively, our findings establish AhWSC1a and AhWSC1b as master regulators of peanut testa pigmentation, elucidate the molecular basis of classical white testa inheritance, and provide genetic targets for precision-breeding of nutritionally enhanced cultivars. Full article