Search Results (342)

Cotton fiber initiation determines the fiber yield, yet the genetic basis underlying lint and fuzz initiation has still not been fully uncovered. Here, map-based cloning was carried out to identify the fiberless mutant genes derived from a cross between Gossypium hirsutum acc. WT and a natural fiberless mutant, fbl_SHZ. The 12:3:1 segregation ratio in F₂ populations (including 1848 and 3100 individuals that were developed in 2016 and 2018, respectively) revealed dominant epistasis, with the fuzz gene exerting dominance over the lint gene. Genetic linkage analysis revealed that GhMYB25like_A12 controls fuzz fiber initiation, while both GhMYB25like_A12 and GhMYB25like_D12 regulate lint fiber development. Sequencing analyses showed that the fbl_SHZ mutant exhibited a K104M mutation in the R2R3 domain of GhMYB25like_A12 and a transposable element insertion in GhMYB25like_D12, leading to fiberless seeds. Knockout of GhMYB25like_A12 produced fuzzless seeds, knockout of GhMYB25like_D12 led to no obvious change in seeds, and knockout of both (GhMYB25like_A12&D12) resulted in fiberless seeds. The 12:3:1 ratio reappeared in the F₂ population developed from the GhMYB25like_A12&D12 mutated plants as female and Jin668 as the male, which further confirmed the genetic interaction observed in fbl_SHZ. RNA-seq analysis revealed that GhMYB25like regulates cotton fiber initiation through multiple pathways, especially fatty acid metabolism. This study elucidates the key genes and their genetic interaction mechanisms governing cotton fiber initiation, providing a theoretical foundation for genetic improvement of cotton fiber traits. Full article

Background: Colorectal cancer (CRC) is strongly influenced by miRNAs as well as the circadian system. Methods: High-throughput sequencing of miRNAs expressed in the rat colon during 24 h light (L)/dark (D) cycle was performed to identify rhythmically expressed miRNAs. The role of miR-150-5p in CRC progression was analyzed in DLD1 cell line and human CRC tissues. Results: Nearly 10% of mature miRNAs showed a daily rhythm in expression. A peak of miRNAs’ levels was in most cases observed during the first half of the D phase of the LD cycle. The highest amplitude was detected in expression of miR-150-5p and miR-142-3p. In the L phase of the LD cycle, the maximum in miR-30d-5p expression was detected. Gene ontology enrichment analysis revealed that genes interfering with miRNAs with peak expression during the D phase influence apoptosis, angiogenesis, the immune system, and EGF and TGF-beta signaling. Rhythm in miR-150-5p, miR-142-3p, and miR-30d-5p expression was confirmed by real-time PCR. Oncogenes bcl2 and myb and clock gene cry1 were identified as miR-150-5p targets. miR-150-5p administration promoted camptothecin-induced apoptosis. Expression of myb showed a rhythmic profile in DLD1 cells with inverted acrophase with respect to miR-150-5p. miR-150-5p was decreased in cancer compared to adjacent tissue in CRC patients. Decrease in miR-150-5p was age dependent. Older patients with lower expression of miR-150-5p and higher expression of cry1 showed worse survival in comparison with younger patients. Conclusions: miRNA signaling differs between the L and D phases of the LD cycle. miR-150-5p, targeting myb, bcl2, and cry1, can influence CRC progression in a phase-dependent manner. Full article

Dunaliella salina, a unicellular and eukaryotic alga, has been found to be one of the most salt-tolerant eukaryotes with a wide range of practical applications. To elucidate the underlying molecular mechanisms of D. salina in response to salinity stress, we performed transcriptome sequencing on samples under different stress conditions. A total of 82,333 unigenes were generated, 4720, 1111 and 2611 differentially expressed genes (DEGs) were identified under high salt stress, oxidative stress and hypertonic stress, respectively. Our analysis revealed that D. salina responds to salinity stress through a complex network of molecular mechanisms. Under high salt stress, starch degradation is regulated by AMY (α-amylase) and PYG (glycogen phosphorylase) with alternative expression patterns. This process is hypothesized to be initially constrained by low ATP levels due to impaired photosynthesis. The clustering analysis of DEGs indicated that starch and sucrose metabolism, as well as glycerol metabolism, are specifically reprogrammed under high salt stress. Glycerol metabolism, particularly involving GPDHs, plays a crucial role in maintaining osmotic balance under salinity stress. Key glycerol metabolism genes were up-regulated under salinity conditions, indicating the importance of this pathway in osmotic regulation. The G3P shuttle, involving mitochondrial GPDHs (c25199_g1 and c23777_g1), contributes to redox imbalance management under high salt, oxidative and hypertonic stresses. Notably, c23777_g1 is involved in the G3P shuttle under high salt, oxidative and hypertonic stresses, while c25199_g1 is specifically induced by hypertonic stress. The R2R3-MYB gene (c23845_g1) may respond to different effects of salinity stress by regulating the transcription of ROS-related genes. Our study provides a detailed understanding of the molecular responses of D. salina to salinity stress. We reveal the critical roles of starch and sucrose metabolism, glycerol metabolism and transcription factors in the D. salina adaptation to salinity. Full article

The establishment of a transient expression system in petals is significant for elucidating gene functions in flowering trees characterized by a prolonged juvenile phase. Genetic improvements in Camellia japonica have been hindered due to the absence of a functional validation platform. In this study, we explored an Agrobacterium-mediated and readily observable transient expression system in camellia petals to systematically optimize four critical factors affecting transformation efficiency. As a result, the bud stage, ‘Banliuxiang’ genotype, OD600 of 1.0, and 1-day co-cultivation achieved the highest intensity of transient expression, and overexpression of the Ruby1 reporter gene induced substantial anthocyanin synthesis, manifested as distinct red pigmentation. Furthermore, the optimized transient expression system revealed that the R2R3-MYB transcription factor CjMYB5, which interacted with CjGL3, promoted anthocyanin biosynthesis in camellia petals by transactivating key DFR structural genes. This transient expression platform not only advances functional genomics studies in ornamental woody species but also lays a foundation for molecular breeding programs in C. japonica. Full article

Background: Rumex patientia (Polygonaceae), a perennial herbaceous species predominantly found in northern temperate regions, has been historically utilized in traditional Chinese medicine for its hematological regulatory properties, including blood cooling, hemostasis, and detoxification. Despite the pharmacological value of this species, unvalidated reference genes compromise precise gene expression profiling. Methods: We initially selected eight candidate genes (ACT, GAPDH, YLS, SKD1, UBQ, UBC, EF-1α, TUA) from R. patientia transcriptomes and then assessed their transcriptional stability using RT-qPCR across root, stem, and leaf tissues under four abiotic stresses: cold, drought, salinity, and heavy metal exposure. Results: ACT emerged as the most stable reference gene in three specific scenarios: root/leaf tissues under cold stress, stems during drought exposure, and roots subjected to salt treatment, revealing distinct tissue–stress response patterns. TUA emerged as the most stable reference in cold- and salt-challenged stems, while SKD1 exhibited superior stability in drought-affected roots/leaves, heavy-metal-stressed tissues, and salt-treated leaves. Validation via the drought-inducible MYB transcription factor confirmed reference gene reliability. Conclusions: This work pioneers a standardized reference gene framework for R. patientia under multi-stress conditions, offering essential methodological foundations for subsequent molecular research in this medicinal plant. Full article

Background: Aluminum (Al) toxicity severely limits Medicago sativa (alfalfa) production on acidic soils, resulting in major yield losses worldwide. The highly conserved miRNA156 (miR156) functions by downregulating at least 11 SQUAMOSA promoter-binding protein-like (SPL) transcription factors in alfalfa, including SPL13, but its role in Al stress remains unclear. This study aimed to investigate the miR156/SPL regulatory network’s function in alfalfa under Al stress. Methods: Gene expression analyses, histochemical staining, nutrient profiling, phenotypic assays, transcriptome profiling, and ChIP-seq were conducted on alfalfa plants with altered miR156 and SPL13 expression to assess their roles in the Al stress response. Results: Al stress induced SPL13 expression while repressing miR156 in the roots. Elevated miR156 intensified Al accumulation, lipid peroxidation, and plasma membrane damage, accompanied by reduced leaf nitrogen, magnesium, sulfur, and phosphorus content. Phenotypically, increased SPL13 enhanced the root length and Al tolerance, whereas SPL13 silencing reduced tolerance. Transcriptome profiling of SPL13-silenced plants identified differentially expressed genes involved in the Al response, including aluminum-activated malate transporters and various transcription factors (GRAS, Myb-related, bHLH041, NAC, WRKY53, bZIP, and MADS-box). ChIP-seq revealed that SPL13 directly regulates genes encoding a protein kinase, cytochrome P450, and fasciclin-like arabinogalactan proteins. Conclusions: The MsmiR156/MsSPL13 network plays a crucial regulatory role in alfalfa’s response to Al toxicity. These findings provide novel genetic targets and foundational knowledge to advance molecular breeding for enhanced Al tolerance in alfalfa. Full article

Starch is the primary component of the endosperm and plays a crucial role in rice quality. Although the enzymes involved in starch synthesis have been extensively studied, the transcription factors that regulate these enzymes remain largely unknown. Here, we identified a MYB family transcription factor, OsMYBR1, that regulates starch biosynthesis in rice. OsMYBR1 is highly expressed during endosperm development. Mutations of OsMYBR1 result in reduced grain thickness and a decrease in 1000-grain weight. The endosperm of osmybr1 mutants exhibit rounded and loosely packed starch granules, decreased amylose content, altered fine structure of amylopectin, and modified physicochemical properties. The analysis of RT-qPCR showed that the expression of several starch-synthesis enzyme-coding genes (SSEGs), including OsGBSSⅠ, OsAGPL1, OsAGPL2, OsBEⅡb, OsISA1, PHOL, and OsSSⅢa, is altered in osmybr1 mutants. Further experiments indicated that OsMYBR1 directly binds to the promoters of OsGBSSⅠ, OsAGPL1, OsAGPL2, OsISA1, OsBEⅡb, and PHOL, resulting in an increase in the expression of OsGBSSⅠ but a decrease in the expression of OsAGPL2, OsISA1, and OsSSⅢa. In contrast, OsMYBR1-overexpressing endosperm appears normal, with starch granule morphology, increased amylopectin content, and improved alkali spreading value, indicating enhanced rice eating and cooking quality (ECQ). These findings suggest that the overexpression of OsMYBR1 could be a promising strategy for improving rice ECQ. Full article

Dendrobium candidum is a traditional Chinese medicinal herb with green and red stems. D. candidum, which has red stems, is highly nutritious. However, there is a need to clarify the mechanisms of transcriptional regulation underlying anthocyanin biosynthesis in D. candidum. In this study, we found that the red stem of D. candidum has a high anthocyanin content and a wide variety of types. Cyanidin derivatives of anthocyanins were found to be responsible for red pigmentation in red leaves. An R3-MYB transcription factor, DcMYB56, which modulates anthocyanin biosynthesis, along with homologs of other plants, was isolated and identified. Compared with that in green stems, DcMYB56 expression in D. candidum red stems markedly increased. The binding of DcMYB56 to the DcCHS8, DcF3′H, DcF3′5′H, and DcANS1 gene promoters controlled DcMYB56 expression levels. The overexpression of DcMYB56 in Arabidopsis thaliana resulted in a red phenotype and substantially increased the anthocyanin content. Our findings suggest that DcMYB56 is important for anthocyanin biosynthesis, which thus sheds new light on the modulation of anthocyanin biosynthesis-associated transcription factors in D. candidum. Full article

The leaf plastochron serves as an indicator of the rate of leaf appearance, biomass accumulation, and branch number, while also impacting plant architecture and seed yield. However, research on the leaf plastochron of crops remains limited. In this study, 2116C exhibited a rapid leaf plastochron compared to ZH18 during both rosette and bud periods. There were significant positive correlations among the leaf plastochron and primary branch number of the F₂ populations (r ranging from 0.395 to 0.635, p < 0.01). Genetic analyses over two years demonstrated that two equally dominant genes might govern the leaf plastochron. Through bulk segregant analysis sequencing (BSA-seq), three novel genomic intervals were identified on chromosomes A02 (9.04–9.48 Mb and 13.52–13.66 Mb) and A04 (19.84–20.14 Mb) of ZS11 and Darmor-bzh reference genomes. By gene functional annotations, single-nucleotide variation (SNV) analyses, transcriptome data from parents, genetic progeny, and natural accessions, we identified ten candidate genes within the intervals, including FLOWERING LOCUS T, RGL1, MYB-like, CYP96A8, BLH3, NIT2, ASK6, and three CLAVATA3/ESR (CLE)-related genes. These findings lay the molecular foundation for further exploration into the leaf plastochron and the implications in plastochron-related breeding in rapeseed. Full article

Spatholobus suberectus Dunn is rich in flavonoids, which were previously demonstrated to respond to changing light conditions. In this study, through weighted gene co-expression network analysis (WGCNA), MYB genes were screened as the potential regulator for these light-intensity-induced changes. One MYB gene, SsMYB106, was chosen for in-depth research. Analysis showed that SsMYB106 was an R2R3-type MYB transcription factor, regulated by light, and involved in controlling the light responses of S. suberectus. SsMYB106 was then transiently overexpressed in S. suberectus flowers and stably overexpressed in Nicotiana benthamiana Domin. SsMYB106 overexpression promoted flavonoids (especially catechins) accumulation, and affected expressions of all the flavonoid biosynthetic pathway genes. In transient overexpression, SsDFR1 was the only significantly decreased gene, while other 17 genes were significantly increased. In stable overexpression, nearly all genes were upregulated or at least unchanged. SsMYB106 overexpression also might function in inhibiting anthocyanin and lignin biosynthesis. This study deepens our understanding of SsMYBs gene functions in regulating and enhancing flavonoids, and would be beneficial for designing high-valued S. suberectus in future. Full article

The R2R3-MYB transcription factor GAMYB plays crucial roles in plant growth and development, but the biological functions of SlGAMYB1 in tomato remain poorly understood. Here, we investigated the roles of SlGAMYB1 by overexpressing a miR159-resistant version (35S:SlGAMYB1^m) in tomato. Transgenic plants exhibited a dwarf phenotype with reduced internode elongation, which was associated with decreased bioactive gibberellin (GA) levels due to transcriptional repression of SlGA3ox1 and activation of SlGA2ox1/2/4/5. Additionally, 35S:SlGAMYB1^m altered leaf morphology by inhibiting cell proliferation through downregulation of cell cycle genes, resulting in larger but fewer epidermal cells. Intriguingly, 35S:SlGAMYB1^m plants displayed increased floral organ number, a process likely mediated by the upregulation of SlWUS rather than GA signaling. These findings demonstrate that SlGAMYB1 regulates diverse aspects of tomato development through both GA-dependent and independent pathways, providing new insights into the functional diversification of GAMYB genes and potential strategies for genetic improvement of tomato architecture and yield. Full article

Purple cowpea accumulates abundant anthocyanins in its epidermis, with R2R3-MYB transcription factors serving as potential regulators of anthocyanin accumulation. This study systematically deciphered the genome-wide characteristics of cowpea R2R3-MYB transcription factors, elucidating their critical roles in plant anthocyanin accumulation. Employing a combined strategy of HMMER Hidden Markov Model searches and BLASTP homology alignment, we successfully identified 127 non-redundant VuR2R3-MYB transcription factors. The encoded proteins exhibited remarkable physicochemical diversity: the average length reached 338.8 amino acid residues, with theoretical isoelectric points distributed between 4.79 and 10.91 residues. When performing a phylogenetic analysis with Arabidopsis homologs, 27 distinct subgroups were identified. Among them, the S4–S7 clades showed conserved protein architectures, which might play a role in regulating the phenylpropanoid pathway. An analysis of the gene architecture revealed patterns of intron/exon organization. Specifically, 85 out of 127 loci (66.9%) presented the typical two-intron configuration, whereas 18 genes had no introns. An investigation of the promoters found that, on average, each gene had 52 cis-regulatory elements. These elements were mainly light-responsive motifs and phytohormone-related elements. Chromosomal mapping indicated an uneven distribution of these genes across 11 chromosomes. Duplication analysis further showed 13 tandem repeats and 54 segmentally duplicated pairs. An analysis of evolutionary constraints demonstrated that purifying selection was predominant (Ka/Ks < 0.5) among paralogous pairs. Through comparative transcriptomics of pod color variants, 19 differentially expressed MYB regulators were identified. These included VuR2R3-MYB23 (MYB3 homolog), VuR2R3-MYB95 (MYB4 homolog), VuR2R3-MYB53 (MYB114 homolog), and VuR2R3-MYB92 (MYB5 homolog), which showed a strong correlation with the patterns of anthocyanin accumulation. Our findings are expected to contribute to elucidating the potential regulatory mechanisms through which R2R3-MYB transcription factors mediate anthocyanin biosynthesis and accumulation. Full article

Cotton fiber length is an important measurement for application in the textile industry, and researchers are seeking to cultivate cotton plants with longer fibers. In this study, cotton fiber genes were systematically reviewed through meta-analysis in terms of extending and shortening fiber and the use of different research technologies for the first time. PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Baidu Xueshu databases were included as literature retrieval sources. A total of 21,467 articles were retrieved, and 45 articles were used in the final analysis. Data analysis was performed using RevMan 5.4 software. To shorten cotton fiber length, clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology was superior to virus-induced gene silencing (VIGS) technology and RNA interference (RNAi) technology [p = 0.002, MD = −1.05, 95% CI (−1.73, −0.37), Chi² = 39.89]. To increase cotton fiber length, CRISPR-Cas9 technology had a similar effect as VIGS technology [p = 0.12, MD = −0.59, 95% CI (−1.33, −0.15), Chi² = 0.17]. When some genes (GhLAC15, GhALDH7B4, GhMDHAR1A/GhDHAR2A, STTM-miR396b, GhMYB44, GhFP2, GhMYB7, GhKNL1, GhTCP4, GhHDA5, GhGalT1, GhKNOX6, GhXB38D, and GhBZR3) were damaged, cotton fiber length increased. Furthermore, we found that after gene interference, the fiber-shortening genes occurred more frequently than the fiber-elongating genes. Synergistic research on these genes may better promote cotton fiber elongation. Full article

Lilies are one of the most popular ornamental flowers in the world. However, the abundant pollen produced in their anthers causes significant inconvenience for producers and consumers. Pollen abortion induced by molecular breeding techniques is one of the effective ways to solve this problem. In this study, the LoTDF1 gene, which is involved in regulating lily anther development, was identified and cloned from lily anthers based on transcriptome data. The open reading frame of LoTDF1 is 936 bp and encodes a protein with 311 amino acids. Multiple sequence alignment and phylogenetic tree analysis revealed that the LoTDF1 protein contained a conserved R2R3 domain, belonging to the MYB transcription factor family. Subcellular localization and transcriptional activation assays demonstrated that LoTDF1 localized to the nucleus and functioned as a transcription activator. The transcriptional activation domain was located within the last 195 amino acids (117–311a) of the C-terminus, and there may be more than one transcriptional activation domain in the region. The expression level of the LoTDF1 gene was highest during the pollen mother cell (PMC) stage of lily anther development (2 cm anther), followed by the tetrad stage (4 cm anther). In situ hybridization experiments further confirmed that LoTDF1 transcripts were predominantly localized in PMCs, tapetal cells, middle layer cells, dyads, and tetrads. The experiment data suggest that LoTDF1 plays a critical role in regulating early anther development in lily. LoTDF1 could be a promising candidate gene for molecular breeding strategies aimed at developing pollen-free lily cultivars to enhance commercial and consumer appeal. Full article

The seed-coat color and seed size have an impact on both the evolutionary fitness and the grain yield of crops. Soybean is a major oil crop, and the seed-coat color and seed size exhibit natural diversity among the different soybean varieties. Here, we found an R2R3-MYB transcription factor of GmMYB62, which shows a significant increase in expression as the seed-coat color changes from yellow to black in different soybean varieties. The GmMYB62 was specifically highly expressed in reproductive organs, especially in floral organs in soybeans. The GmMYB62 encodes a nuclear protein that contains two MYB domains. In the phylogenetic analysis, the GmMYB62 was relatively conserved after the divergence of the monocots and dicots, and it also grouped with transcriptional repressors of MYBs in anthocyanin synthesis. The GmMYB62 was overexpressed in Arabidopsis and the seeds displayed a pale-brown coat in GmMYB62 overexpression lines, in contrast to the dark-brown seed coat observed in wild-type of Col-0. The anthocyanin content in the GmMYB62 overexpression lines was dramatically reduced when compared to Col-0. Additionally, the seeds in overexpression lines showed shorter lengths, larger widths, and lower thousand-seed weights than those in Col-0. Furthermore, the genes related to anthocyanin synthesis and seed size regulation were investigated, and expression of eight genes that involved in anthocyanin synthesis pathway, like chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), and anthocyanidin synthase (ANS) were severely inhibited in the GmMYB62 overexpression lines when compared to Col-0. In addition, the ARGOS-LIKE (ARL), B-Type Cyclin 1 (CYCB1), and enhancer of DA1-1 (EOD3), which govern cell expansion and proliferation, were highly expressed in GmMYB62 overexpression lines when compared to Col-0. Overall, this study sheds new light on the control of seed-coat color and seed size by GmMYB62 and provides potentially valuable targets for improving crop seed quality. Full article