Search Results (53)

The Jumonji C (JMJ-C) domain-containing gene family regulates epigenetic and developmental processes in plants. We identified 55 JMJ-C genes in Populus alba × Populus glandulosa using HMM and BLASTp analyses. Chromosomal mapping revealed an asymmetric distribution with conserved synteny. Phylogenetic reconstruction revealed that PagJMJ genes segregate into five evolutionarily conserved subfamilies, exhibiting classification patterns identical to those of Arabidopsis thaliana and Populus trichocarpa. Synteny analysis indicated a closer relationship with P. trichocarpa than with A. thaliana. Motif and promoter analyses highlighted subfamily-specific features and diverse cis-elements, particularly light-responsive motifs. Expression profiling revealed tissue-specific patterns, with key genes enriched in roots, vascular tissues, and leaves. Developmental analysis in cambium and xylem identified four expression clusters related to wood formation. Co-expression analysis identified six key PagJMJ genes (PagJMJ6, 29, 34, 39, 53, and 55) strongly associated with wood formation-related transcription factors. ChIP-qPCR analysis revealed that key genes co-expressed with PagJMJ genes were marked by H3K4me3 and H3K9me2 modifications. These findings provide insights into the evolutionary and functional roles of PagJMJ genes in poplar vascular development and wood formation. Full article

This study aimed to investigate the cracking characteristics of various sweet potato germplasm resources, explore their genetic associations, and identify crack-resistant varieties. Using 40 sweet potato varieties as experimental materials, we systematically analyzed their cracking traits and assessed 24 parameters. The results indicated that genotypic differences significantly influenced sweet potato cracking (p = 1.11 × 10⁻¹⁶). Correlation analyses revealed that skin thickness (r = −0.81, p < 0.01), skin hardness (r = −0.50, p < 0.01), and starch content (r = −0.51, p < 0.01) were highly significantly negatively correlated with cracking incidence. Microscopic observations of the cell structure revealed that the development quality of the cork cambium and vascular cambium during the secondary growth stage plays a crucial role in maintaining the structural stability of the tuber skin, whereas the internal expansion force during the rapid growth phase is a direct factor that induces cracking. A multiple regression prediction model (R² = 0.85) was established based on ten core indices. Furthermore, a comprehensive evaluation system for sweet potato cracking resistance was developed by integrating principal component analysis and the entropy-weighted TOPSIS model (kappa = 0.752, p = 5 × 10⁻⁶), identifying seven extremely crack-resistant and nine crack-resistant varieties. This study is the first to construct a multidimensional evaluation system for cracking traits in sweet potato, offering a reference for breeding crack-resistant varieties and developing cultivation, prevention, and management strategies. Full article

Proteins of the PF10950 family feature the DUF2775 domain of unknown function. The most studied are specific tissue (ST) proteins with tandem repeats, which are putative precursors of cyclopeptide alkaloids. Here, we study uncharacterised short ST (SST) proteins with the DUFF2775 domain by analysing 194 sequences from 120 species of 39 taxonomic families in silico. SST proteins have a signal peptide and their size and several other characteristics depend on their individual taxonomic family. Sequence analyses revealed that SST proteins contain two well-conserved regions, one resembling the ST repeat, which could constitute the core of cyclopeptide alkaloids. We studied the unique SST1 gene of Arabidopsis thaliana, which is adjacent to and co-expressed with a gene encoding a protein with a BURP domain, associated with cyclopeptide production. The empirical analysis indicated that the SST1 promoter is mainly activated in the roots, where most of the transcripts accumulate, and that the SST1 protein accumulates in the root vascular cambium. At the cellular level, SST fused to GFP appears in vesicles that co-localise with the endoplasmic reticulum and the vacuole. Thus, SSTs are a new type of PF10950 protein found in core eudicots with two conserved regions that could be involved in root biology. Full article

Anthocyanins, crucial flavonoids in plants, enhance stress tolerance in alfalfa and are attracting attention due to their antioxidant properties. This study analyzed red- and green-stemmed alfalfa using spectrophotometry, frozen sections, and LC-MS/MS. Anthocyanins were concentrated in stem vascular cambium, with red stems peaking at 61.08 mg g⁻¹ DW during the bud stage. Seven anthocyanidins were identified, with their corresponding aglycones including cyanidin, peonidin, and malvidin. At early flowering, red-stemmed alfalfa contained 35 classes of anthocyanins compared to 17 in green-stemmed varieties, with cyanidin-3-O-glucoside levels significantly higher in red stems (4.423 μg g⁻¹, p < 0.05). Red-stemmed alfalfa also showed higher contents of acid detergent fiber, crude fat, Cu, Fe, and Zn (p < 0.05), especially Zn (p < 0.01). Correlation analysis revealed a strong positive link between cyanidin and crude fat (Spearman’s ρ = 0.93, p < 0.01) and a significant negative correlation with neutral detergent fiber (ρ = −0.88, p < 0.05). Cyanidin and peonidin are associated with stem color differentiation, with cyanidin contributing predominantly to red pigmentation, whereas zinc and crude fat exhibit a synergistic correlation with anthocyanin accumulation. These findings may inform breeding strategies to develop anthocyanin-enriched alfalfa. Full article

The secondary lateral meristem—the vascular cambium (hereafter cambium)—is the largest meristem of the plant kingdom. It is almost always composed of two types of stem cells: (1) the axial (fusiform) initials, the most common and better known and studied, and (2) the ray initials that give rise to the vascular rays (hereafter rays), i.e., the radial component of the secondary xylem and phloem, which are less common and much less studied, and in many studies ignored. There is great flexibility in switching from axial initials to ray initials and vice versa. Ray initials commonly compose ca. 10–40% of the cambium of mature tree trunks, but nothing or very little in typical young model plants used for molecular cambial studies, such as Arabidopsis thaliana and young internodes of Populus spp. cuttings. I suggest paying more attention to the regulation of the differentiation of ray initials and their derivatives, and to the little-known complicated relations between the axial and ray cambial initials when they contact each other, as well as the special development of pits in their derivatives in cambial molecular studies by using mature trunks of various large woody plants rather than studying A. thaliana or young internodes of Populus cuttings. Full article

The presence of shade-tolerant tree invaders has been recently noted in tropical and temperate forest understories. Maximum growth rate is an important trait for exotic trees becoming invaders in a forest. This study aimed to determine the growth rate of Eriobotrya japonica in a secondary cloud forest in central Veracruz, Mexico. The objectives of this study were to determine wood density, tree ring boundaries and number, and their relationship to diameter at breast height (DBH) and climate data. Tree ring counts were obtained using Python-based software with subsequent visual validation. Growth rates were measured using diametric tape, dendrometric bands, and the pinning method. The number of rings increased with DBH, presenting values ranging from 14 to 27. Tree rings were delimited by fibers that were five times narrower in the ring limit zone than in the intra-ring zone. The growth ring delimitation zones were formed when vascular cambium activity stalled during the relatively dry-cold season (January–February). The growth rate of E. japonica was statistically similar (ca. 0.2 mm yr⁻¹) regardless of the method employed to measure it. Relative growth rate was low (0.02 cm cm⁻¹ yr⁻¹). Wood density (0.76 g cm⁻³) values lay within the upper values for mature forest trees. Eriobotrya japonica is a potential invader, with traits such as high wood density and a relatively low growth rate, which are characteristic of the shade-tolerant tree species. Full article

Heartwood, serving as the central constituent of the xylem, plays a crucial role in the growth, development, and resilience of trees. The process of heartwood formation constitutes a complex biological phenomenon influenced by various factors. A thorough examination of the mechanisms underpinning heartwood formation not only enhances our understanding of the growth and developmental paradigms regulating trees but also provides essential theoretical support and practical insights for the timber industry, forestry management, and ecological conservation. This paper offers an overview of the foundational processes involved in heartwood formation in plants. Furthermore, it presents a comprehensive review of the latest research advancements in this domain, covering five key aspects: metabolism, hormonal regulation, transcriptional regulation, cell biology, and environmental influences. This review serves as a valuable basis for future research endeavors in related academic fields. Full article

All multicellular organisms undergo senescence, but the continuous division of the vascular cambium in plants enables certain tree species to survive for hundreds or even thousands of years. Previous studies have focused on the development of the vascular cambium, but the mechanisms regulating age-related changes remain poorly understood. This study investigated age-related changes in the vascular cambium of P. euphratica trees aged 50 to 350 years. The number of cambium cells in the 50-year-old tree group was 10 ± 2, while the number of cambium cells in the 200-year-old and 350-year-old tree groups significantly decreased. The thickness of the cambium cells exhibited a similar trend. In addition, the net photosynthetic and transpiration rates continue to increase with age, but no notable differences were found in factors like average leaf area, palisade tissue thickness, and stomatal density. A total of 6491 differentially expressed genes (DEGs) were identified in the vascular cambium of P. euphratica at three distinct ages using RNA sequencing. The expression patterns of DEGs associated with cell division and differentiation, lignin biosynthesis, plant hormones, and transcription factors were analyzed. DEGs related to XTH, EXP, PAL, C4H, ABA, Br, GA, and others are highly expressed in older trees, whilst those encoding expansins, kinases, cyclins, 4CL, Auxin, Eth, SA, and others are more prevalent in younger trees. Gene family members, such as NAC, MYB, HD-ZIP III, WRKY, and GRF, have various regulatory functions in the vascular cambium. The findings offer insights into how ancient P. euphratica trees maintain vitality by balancing growth and aging, providing a foundation for future research on their longevity mechanisms. Full article

Taxodium ascendens has been extensively cultivated in the wetlands of the Yangtze River in south China and has significantly contributed to ecology and timber production. Until now, research on T. ascendens genomics has yet to be conducted due to its large and complex genome, which hinders the development of T. ascendens genomic resources. Combined with the microstructural changes during cambium cell differentiation across various growth periods, we investigate the transcriptome expression and regulatory mechanisms governing cambium activity in T. ascendens. Using RNA sequencing (RNA-Seq) technology, we identified the genes involved in the cambium development of cells at three stages (dormancy, reactivation, and activity). These genes encode the regulatory and control factors associated with the cambial activity, cell division, cell expansion, and biosynthesis of cell wall components. Blast comparison revealed that three genes (TR_DN69961_c0_g1, TRINITY_DN17100_c1_g1, TRINITY_DN111727_c0_g1) from the MYB and NAC families might regulate transcription during lignin formation in wood thickening. These results illustrate the dynamic changes in the transcriptional network during vascular cambium development. Additionally, they shed light on the genetic regulation mechanism of secondary growth in T. ascendens and guide further elucidation of the candidate genes involved in regulating cambium differentiation and wood formation. Full article

Indented growth rings were found long ago to be experimentally induced in Pinus halepensis Miller by thin parallel axial scratching of the bark up to the vascular cambium with a sharp blade. Here, we show that when the bark and vascular cambium of P. halepensis are wounded by wide and long parallel axial wounds (“windows”) rather than by thin scratches, the induced indented growth rings become dramatically more indented. All ten trees that were wounded by long parallel “windows” responded with very strong growth (especially in the first two years) that resulted in the formation of very conspicuous, extremely indented growth rings in the wood formed in between the long and wide woundings. This is true for both the trunks that were wounded all around their circumference and those that were wounded only in part of their circumference. We also suggest further lines of research. Full article

Wildfires are unplanned conflagrations perceived as a threat by humans. However, fires are essential for the survival of fire-adapted plants. On the one hand, wildfires cause major damage worldwide, burning large areas of forests and landscapes, threatening towns and villages, and generating high levels of air pollution. On the other hand, fire-adapted plants (pyrophytes) in the fire landscapes of the Earth are able to survive exposure to heat (e.g., because of their thick bark, which protects their living tissue) and benefit from fire directly (e.g., fire initiates cone opening and seed release) or indirectly (e.g., fewer competing plants of fire-sensitive species remain, seeds germinate in the ash-fertilized soil). We present the experimental set-up and results of a fire experiment on bark samples used as a basis to assess the fire tolerance of various trees. Fire tolerance is defined as the ability of a tree to survive a surface fire (up to 200 °C and 5 min duration). The measure of the fire tolerance for a tree species is the time taken for the vascular cambium under the insulating bark to reach the critical temperature of 60 °C. Within an educational module, we provide worksheets for teachers and students enabling them to analyze the fire tolerance of various tree barks. Full article

In potato, phloem tissues transport sugars and signal molecules to the tuber for growth and storage. The CLAVATA3/ESR-like (CLE) family of plant peptides plays an important role in regulating plant development. In this study, we identified a set of phloem-expressed CLE genes in Solanum tuberosum L. (StCLEs). We analyzed the phloem transcriptome of potato and found that 10 out of 41 StCLE genes were expressed in phloem cells, with StCLE12 and StCLE19 showing the highest expression levels. StCLE12 has an identical CLE domain to the Arabidopsis TDIF peptides, which are known to play a crucial role in maintaining the vascular meristem. StCLE19 has the highest sequence similarity to the Arabidopsis CLE25 peptide, which is involved in the formation of the phloem element and signaling in response to dehydration stress. The overexpression of StCLE12 and another potato TDIF-like gene, StCLE8, promoted vascular cell proliferation and delayed leaf senescence. On the other hand, plants with overexpression of StCLE19 were unable to form adventitious roots and demonstrated the absence of ordered cambium cell layers in the vascular bundles. Full article

Timber, the most prevalent organic material on this planet, is the result of a secondary xylem emerging from vascular cambium. Yet, the intricate processes governing its seasonal generation are largely a mystery. To better understand the cyclic growth of vascular tissues in elm, we undertook an extensive study examining the anatomy, physiology, and genetic expressions in Ulmus pumila. We chose three robust 15-year-old elm trees for our study. The cultivars used in this study were collected from the Inner Mongolia Autonomous Region in China and nurtured in the tree farm of Shandong Normal University. Monthly samples of 2-year-old elm branches were taken from the tree from February to September. Marked seasonal shifts in elm branch vascular tissues were observed by phenotypic observation: In February, the cambium of the branch emerged from dormancy, spurring growth. By May, elms began generating secondary xylem, or latewood, recognized by its tiny pores and dense cell structure. From June to August, there was a marked increase in the thickness of the secondary xylem. Transcriptome sequencing provides a potential molecular mechanism for the thickening of elm branches and their response to stress. In February, the tree enhanced its genetic responses to cold and drought stress. The amplified expression of CDKB, CYCB, WOX4, and ARF5 in the months of February and March reinforced their essential role in the development of the vascular cambium in elm. Starting in May, the elm deployed carbohydrates as a carbon resource to synthesize the abundant cellulose and lignin necessary for the formation of the secondary wall. Major genes participating in cellulose (SUC and CESA homologs), xylan (UGD, UXS, IRX9, IRX10, and IRX14), and lignin (PAL, C4H, 4CL, HCT, C3H, COMT, and CAD) biosynthetic pathways for secondary wall formation were up-regulated by May or/and June. In conclusion, our findings provided a foundation for an in-depth exploration of the molecular processes dictating the seasonal growth of elm timber. Full article

Carrot (Daucus carota L.) is a highly consumed vegetable rich in carotenoids, known for their potent antioxidant, anti-inflammatory, and immune-protecting properties. While genetic and molecular studies have largely focused on wild and Western carrot cultivars (cvs), little is known about the evolutionary interactions between closely related Eastern and Western cvs. In this study, we conducted comparative transcriptome profiling of root tissues from Eastern (UHSBC-23-1) and Western (UHSBC-100) carrot cv. to better understand differentially expressed genes (DEGs) associated with storage root development and vascular cambium (VC) tissue patterning. Through reference-guided TopHat mapping, we achieved an average mapping rate of 73.87% and identified a total of 3544 DEGs (p < 0.05). Functional annotation and gene ontology classification revealed 97 functional categories, including 33 biological processes, 19 cellular components, 45 metabolic processes, and 26 KEGG pathways. Notably, Eastern cv. exhibited enrichment in cell wall, plant-pathogen interaction, and signal transduction terms, while Western cv. showed dominance in photosynthesis, metabolic process, and carbon metabolism terms. Moreover, constructed gene regulatory network (GRN) for both cvs. obtained orthologs with 1222 VC-responsive genes of Arabidopsis thaliana. In Western cv, GRN revealed VC-responsive gene clusters primarily associated with photosynthetic processes and carbon metabolism. In contrast, Eastern cv. exhibited a higher number of stress-responsive genes, and transcription factors (e.g., MYB15, WRKY46, AP2/ERF TF connected via signaling pathways with NAC036) were identified as master regulators of xylem vessel differentiation and secondary cell wall thickening. By elucidating the comparative transcriptome profiles of Eastern and Western cvs. for the first time, our study provides valuable insights into the differentially expressed genes involved in root development and VC tissue patterning. The identification of key regulatory genes and their roles in these processes represents a significant advancement in our understanding of the evolutionary relations and molecular mechanisms underlying secondary growth of carrot and regulation by vascular cambium. Full article

The periosteum is a thin layer of connective tissue covering bone. It is an essential component for bone development and fracture healing. There has been considerable research exploring the application of the periosteum in bone regeneration since the 19th century. An increasing number of studies are focusing on periosteal progenitor cells found within the periosteum and the use of hydrogels as scaffold materials for periosteum engineering and guided bone development. Here, we provide an overview of the research investigating the use of the periosteum for bone repair, with consideration given to the anatomy and function of the periosteum, the importance of the cambium layer, the culture of periosteal progenitor cells, periosteum-induced ossification, periosteal perfusion, periosteum engineering, scaffold vascularization, and hydrogel-based synthetic periostea. Full article