Search Results (59)

Cauliflower (Brassica oleracea var. botrytis) curd formation is a highly complex developmental process governed by tightly coordinated genetic and physiological regulation. Here, we performed transcriptome sequencing of curd and peduncle tissues across multiple developmental stages, generating 171.52 Gb of high-quality data. Genes associated with photosynthesis and glucosinolate biosynthesis were strongly upregulated in the shoot apical meristem (SAM), highlighting substantial metabolic investment during the pre-initiation phase of curd morphogenesis. Key floral transition regulators, particularly AP2 and MADS-box transcription factors, were activated to drive the vegetative-to-reproductive switch and initiate curd primordia, ultimately giving rise to the arrested inflorescence architecture characteristic of cauliflower. Furthermore, hormone signaling pathways—including auxin (AUX), jasmonic acid (JA), and brassinosteroid (BR)—showed marked activation during SAM proliferation and peduncle elongation, underscoring their crucial roles in structural patterning. Collectively, our findings delineate an integrated regulatory network that links metabolic activity, hormone signaling, and developmental programs, providing novel molecular insights into curd formation and identifying potential breeding targets for the genetic improvement of Brassicaceae crops. Full article

Root suckering is a key mode of clonal propagation in white poplar group, such as aspens (Populus section Leuce), enabling rapid vegetative spread, yet the molecular triggers remain elusive. Here, we developed a rapid protocol that produces abundant root suckers with the root cutting of white poplar (Populus davidiana × P. bolleana) roots in greenhouse. Anatomical analyses and daily resolution transcriptomes resolved three sequential developmental stages: primordium initiation (Days 0–1), SAM (shoot apical meristem) establishment (Days 1–4), and organ differentiation/growth (Days 4–6). Weighted gene co-expression network analysis revealed that auxin- and cytokinin-mediated signaling, integrated with nitrogen metabolism, orchestrates SAM formation and maintenance. Exogenous application of 0.5–1.0 mg L⁻¹ NAA suppressed sucker emergence by 48–60%, whereas inhibition of cytokinin biosynthesis with lovastatin reduced initiation by 60%. These data establish that auxin negatively regulates and cytokinin is indispensable for de novo shoot apical meristem establishment during poplar root-suckering, underscoring that a precise auxin–cytokinin balance governs the timing and extent of this developmental process. Cambial regulators WUSCHEL-Related Homeobox 4-1/2 (WOX4-1/2), together with core meristem regulators WUSCHEL (WUS) and SHOOT MERISTEMLESS (STM), were specifically induced during SAM establishment that underpin vascular integration between the nascent shoot and the parental root. These results uncover the molecular pathway controlling root suckering and provide potential targets for molecular breeding to either enhance or suppress root suckering in Populus. Full article

Climate change and widespread micronutrient deficiencies threaten food security in the semi-arid tropics. Finger millet (Eleusine coracana (L.) Gaertn.) is a climate-resilient “nutri-cereal” rich in calcium, zinc, iron and dietary fiber. Finger millet is a promising crop for addressing climate stress and nutrient deficiencies. However, it remains under-explored and relatively neglected in breeding and genetic improvement programs compared to major cereals. This review synthesizes recent biotechnological advances and outlines future directions for finger millet improvement. Foundational resources now include a chromosome-scale reference genome, expanding transcriptome, diverse global germplasm panels, and growing reports of genome-wide association studies (GWAS) and quantitative trait loci (QTL) for key traits including yield, stress tolerance, blast resistance, and mineral contents. Tissue culture studies reported both somatic embryogenesis and direct regeneration. Stable genetic transformation has been achieved in finger millet via Agrobacterium-mediated methods, particularly using shoot apical meristem (SAM) and by biolistics (gene gun) methods. Genome editing has not yet been reported, but we propose a practical roadmap leveraging reported tissue culture genetic transformation protocols for applying the CRISPR/Cas system for trait improvements. Using new biotechnological methods, along with pangenome, speed breeding, and helpful microbiomes, will make finger millet a strong and reliable food source for the future. Full article

Soybean (Glycine max (L.) Merr.) flowering time and plant height are critical agronomic traits that significantly influence yield and environmental adaptability. To clarify the regulatory mechanisms of flowering-related genes and their associations with plant height, a genome-wide identification of such genes in soybean were performed. This analysis used Arabidopsis thaliana flowering genes as references, employing BLASTP searches and pathway classification. All of the identified flowering-related genes were classified into eight regulatory pathways, with the photoperiod pathway (Ph) being the most prominent. Evolutionary and expression analyses revealed that core regulators (e.g., GmFTs, GmSOC1s) are conserved across pathways and are preferentially expressed in shoot apical meristems (SAMs). Additionally, both flowering-related genes and key hormones (e.g., IAA, GA, ABA) exhibited rhythmic responses to light signals. CRISPR-Cas9-mediated validation confirmed that genes GmSAUR46b regulates both flowering time and plant height, as mutants of this gene showed early flowering and reduced height. Notably, a large proportion of previously mapped flowering genes overlapped with our identified ones, while some remained undetected, likely due to whole-genome duplication and adaptive evolution, which generate new regulatory networks. Most of the identified flowering-related genes, however, have not been mapped, which highlights substantial uncharacterized potential in soybean flowering and plant height regulation. This provides a valuable molecular framework to guide soybean molecular breeding for enhanced yield and environmental adaptability. Full article

Background: The flowering transition is a critical process determining the onset of reproductive development and fruit production. The molecular mechanisms underlying this process in coconuts are poorly understood; however, recent studies have identified CnHd3a as a potential regulator of the floral transition in coconuts. Methods: In this study, we characterized the molecular structure of CnHd3a and analyzed its alternative splicing forms in tall and dwarf varieties of coconut palms during the flowering transition. We used qRT-PCR to measure the expression levels of CnHd3a at different developmental stages. Results: CnHd3a was expressed in leaves and the shoot apical meristem (SAM) during the flowering transition in both coconut varieties and flower tissues during flower development. Interestingly, the expression levels of complex isoforms of CnHd3a were higher in the leaves of dwarf coconuts than in those of tall coconuts, suggesting their involvement in shortening the vegetative growth phase of dwarf coconuts. The gene structure of CnHd3a was found to be conserved across different plant species, indicating the evolutionary conservation of the floral transition process. Conclusions: Our findings provide insight into the molecular mechanisms underlying the floral transition and flower development processes in coconut palm. The tissue-specific expression patterns of CnHd3a isoforms show their potential roles in growth and development. Further investigations focusing on the functional characterization of CnHd3a isoforms will have practical implications for coconut breeding and cultivation strategies. Full article

Viral infections in stone fruit crops cause substantial economic losses across all sectors of production. Despite their significance, viruses affecting stone fruits remain under-investigated in Kazakhstan. Among these, plum pox virus (PPV, genus Potyvirus, family Potyviridae), commonly known as Sharka, is the most critical viral pathogen worldwide, severely threatening the sustainable cultivation of stone fruits and posing risks to food security. This study aimed to evaluate virus management strategies in stone fruit crops to facilitate the production of healthy planting material from valuable genotypes. Field surveys were conducted in plum and apricot orchards located in the Almaty region (Southeast Kazakhstan) and the Saryagash region (Southern Kazakhstan). Plant samples were tested for the presence of the following viruses: apple chlorotic leaf spot virus (ACLSV), apple mosaic virus (ApMV), PPV, prune dwarf virus (PDV), prunus necrotic ringspot virus (PNRSV), cherry green ring mottle virus (CGRMV), and myrobalan latent ringspot virus (MLRSV). Real-time RT-PCR diagnostics confirmed the presence of PPV in the ‘Stanley’ and ‘Ansar’ cultivars and Prunus armeniaca genotypes, while both PPV and ACLSV were detected in the ‘Ayana’ variety. Chemotherapy (Ribavirin), thermotherapy, cryotherapy, and shoot apical meristem (SAM) culture, both individually and in combination, were used to eliminate viruses and regenerate virus-free plants. Successful virus eradication was achieved for PPV and ACLSV. However, the ‘Stanley’ and ‘Ansar’ cultivars did not survive the treatment process, likely due to high thermo- or cryo-sensitivity. As a result of this research, an in vitro collection of virus-free plants was established, comprising eight rootstocks, six plum cultivars, and three apricot genotypes. Full article

The peptide ligands of the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) family have been previously identified as essential signals for both short- and long-distance communication in plants, particularly during stem cell homeostasis, cell fate determination, and growth and development. To date, most studies on the CLE family have focused on model plants and especially those involving stem and apical meristems. Relatively little is known about the role of CLE peptides in tall trees and other plant meristems. In this review, we summarize the role of CLE genes in regulating plant Root Apical Meristem (RAM), Shoot Apical Meristem (SAM), Procambium, Leaf and Floral Meristem (FM), as well as their involvement in multiple signaling pathways. We also highlight the evolutionary conservation of the CLE gene family and provide a comprehensive summary of its distribution across various plant developmental tissues. This paper aims to provide insights into novel regulatory networks of CLE in plant meristems, offering guidance for understanding intercellular signaling pathways in forest trees and the development of new plant organs. Full article

Populus species are important resources for ecological conservation and certain industry productions, and are also considered model tree species for scientific research. For tree species, in vitro plant regeneration is an important method of propagation due to the advantage of high multiplication rate. Although many molecular determinants for poplar regeneration have been investigated, the complete regulatory hierarchy network remains unclear. In this study, we tracked the temporal changes of endogenous hormone contents, physiological characteristics and transcriptional profiles during callus induction and adventitious organogenesis in a stem of Populus alba L. to explore the regulatory dynamics of in vitro regeneration in poplars. The results imply that auxin may promote the formation of callus in P. alba by activating the expression of WOX11/12. By up-regulating the expression of CUC1/2, the development of callus begins to initiate apical meristem (SAM) at day 12. The cytokinin-mediated pathway regulates the adventitious shoot formation by ESR1 and WUS. The precursors of active gibberellin GA1, GA53 and GA19 were accumulated in the early stage of callus induction, and then they continued to decrease. JA may function on adventitious shoot regeneration due to its accumulation after 12 days of induction. The dominant hormonal components and regulatory factors during regeneration were identified. Based on the results, a regeneration pathway regulated by auxin and cytokinin for poplars is proposed. The key regulators identified in this study will accelerate the exploration and understanding of the asexual reproduction mechanism of poplar trees. Full article

The determinate inflorescence trait of Brassica napus L. is associated with various desirable agricultural characteristics. BnTFL1s (BnaA10.TFL1 and BnaC09.TFL1), which encode the transcription factor TERMINAL FLOWER 1 (TFL1), have previously been identified as candidate genes controlling this trait through map-based cloning. However, the mechanism underlying the effects of the BnTFL1 proteins remains unclear. Further, proteins generally interact with each other to fulfill their biological functions. The objective of this study was to construct a cDNA library of the shoot apical meristem (SAM) of B. napus and screen for proteins that interact with BnTFL1s, to better understand its mechanism of action. The recombination efficiency of the yeast two-hybrid (Y2H) library that we constructed was 100%, with insertion fragment lengths ranging from 750 to 2000 bp and a capacity of approximately 1.44 × 10⁷ CFUs (colony-forming units), sufficient for screening protein interactions. Additionally, the bait vector pGBKT7-BnTFL1s was transformed into yeast cells alongside positive and negative controls, demonstrating no toxicity to the yeast cells and no self-activation. This bait was used to screen the SAM cDNA library of B. napus, ultimately identifying two BnTFL1s-interacting proteins: 14-3-3-like protein GF14 omega GRF2. These interactions were verified through one-to-one interaction experiments. This study provides a foundation for further research on the biological functions of the BnTFL1s genes and their regulatory role in inflorescence formation in B. napus, while providing a reference for studying similar mechanisms in other plants. Full article

White clover (Trifolium repens) is vulnerable to drought stress. In response to abiotic stress, plants are regulated by NAC transcription factors. The NAC in white clover has not been thoroughly documented until recently. We have identified one white clover NAC transcription factor called TrNAC002. TrNAC002’s coding sequence is localized to specific regions on the 3P and 5O chromosomes of white clover and is part of a single-copy nuclear gene. Subcellular localization demonstrates that TrNAC002 is located in the nucleus, while the transcriptional activity assay indicates its transcriptional activity. Arabidopsis plants overexpressing TrNAC002 (OE) exhibit enlarged leaves and increased lateral root growth compared to the wild type (WT). Additionally, the expression levels of the shoot apical meristem (SAM), WUSCHEL (WUS), DNA-binding protein (DBP), and auxin-induced in root cultures3 (AIR3) genes are significantly higher in OE as compared to WT. These findings imply that TrNAC002 could promote vegetative growth by increasing the expression of these genes. Under natural drought stress, OE can survive in dry soil for a longer period of time than WT. Furthermore, OE exhibits a lower level of reactive oxygen species (ROS) level and a higher content of flavonoids than WT. This is also positively correlated with an increased flavonoid content. In white clover, the expression of TrNAC002, chalcone synthase (CHS), and chalcone isomerase (CHI) in leaves demonstrates significant upregulation after drought stress and ABA treatment, as does the flavonoid content. However, the pTRV-VIGS experiment suggests that pTRV2-TrNAC002 white clover shrinks compared to the Mock and Water controls. Additionally, pTRV2-TrNAC002 white clover displays a statistically higher malondialdehyde (MDA) content than the Mock and Water controls, and a significantly lower level of total antioxidant activities, flavonoid content, CHS and CHI relative expression than that of the Mock and Water controls. These findings indicate that TrNAC002 responds to drought and modulates flavonoid biosynthesis in white clover. This study is the first to suggest that TrNAC002 likely responds to drought via ABA and enhances plant drought resistance by synthesizing flavonoids. Full article

The reduction of leaves was a key event in the evolution of the succulent syndrome in Cactaceae, evolving from large, photosynthetic leaves in Pereskia to nearly suppressed microscopic foliar buds in succulent Cactoideae. This leaf reduction was accompanied by the development of spines. Early histological studies, dating back a century, of the shoot apical meristem (SAM) in several species concluded that, in succulent cacti, axillary buds became areoles and leaves transformed into spines. However, these conclusions were based on limited observations, given the challenges of obtaining SAM samples from long-lived, often endangered species. Here, we present a complete study of early aerial organ development in seedlings of the iconic Carnegiea gigantea (saguaro), characterizing the different stages of seedling development. We focus on the SAM to track the emergence and development of primordia and aerial organs, closely following the spine development from undifferentiated structures. We demonstrate that young, few-days-old saguaro seedlings provide a valuable model for morpho-anatomical and molecular studies in Cactaceae. We also outline optimal laboratory practices for germinating saguaro seeds and conducting histological studies. Our observations confirm the absence of clear foliar structures and the presence of a distinct type of primordia, hypothesized to be foliar but lacking definitive foliar features. Based on our observations and a review of the literature, we revive the discussion on the ontogenetic origin of spines and propose saguaro seedlings as a promising model for studying the genetic identity of SAM primordia. Full article

Liparis loeselii (L.) Rich, an endangered member of the Orchidaceae family, is found in alkaline fens. With the declining populations of L. loeselii, there is a pressing need to reintroduce this species in Central Europe. As in vitro germination is a crucial tool for obtaining plants for introduction into the environment, we looked at the morphological changes occurring during the early stages of L. loeselii development in vitro. As the early stages of orchid development, especially the protocorm stage, are thought to be responsible for SAM formation and the initiation of symbiotic association, we focused on cell wall elements whose epitopes have been found in similar processes in other species: the extensin and pectin rhamnogalacturonan I (RG-I) side chain epitopes. We addressed the following questions: Does the cell wall of L. loeselii change its composition during the early stages of development, as noted in other species? Are there noticeable similarities in the cell wall to organs of different species whose function is to contact microorganisms? Are there regularities that allow the recognition of individual structures on this basis? Immunolocalization revealed changes in the distribution of certain extensins (JIM11 and JIM20) and RG-I (LM5 and LM6) side chain epitopes. Extensins, a type of cell wall protein, were observed during the initial stages of the formation of PLB and the shoot apical meristem of protocorms and PLBs. RG-I, on the other hand, was found to play a significant role in the development of the protocorm and PLB. In pseudobulbs, which appeared on the protocorms, extensins occurred in their storage part. However, RG-I side chains (1→4)-β-galactans (LM5), and (1→5)-α-L-arabinans (LM6) were not found in pseudobulbs. We revealed that a common feature of protocorms and PLBs was an increased amount of extensins, which were detected with the JIM11 antibody, and pectins, which were detected with the LM5 antibody, that were present together, which may prove helpful in determining the identity of the induced structures and distinguishing them from pseudobulbs. Thus, our study unveiled the role of extensins and RG-I during the growth of protocorms and PLBs. We suggest that PLBs may mimic the wall remodelling that occurs in protocorms, which indicates that using cell wall components is an invitation to be colonised by a fungal partner. However, this needs to be tested in future research. The findings of this research can help interpret future studies on the propagation, acclimatisation, and introduction of L. loeselii into the natural environment. Full article

Plant grafting using dwarfing rootstocks is one of the important cultivation measures in the sweet cherry (Prunus avium) industry. In this work, we aimed to explore the effects of the dwarfing rootstock “Pd1” (Prunus tomentosa) on sweet cherry ‘Shuguang2’ scions by performing morphological observations using the paraffin slice technique, detecting GA (gibberellin) and IAA (auxin) contents using UPLC-QTRAP-MS (ultra-performance liquid chromatography coupled with a hybrid triple quadrupole-linear ion trap mass spectrometer), and implementing integration analyses of the epigenome and transcriptome using whole-genome bisulfite sequencing and transcriptome sequencing. Anatomical analysis indicated that the cell division ability of the SAM (shoot apical meristem) in dwarfing plants was reduced. Pd1 rootstock significantly decreased the levels of GAs and IAA in sweet cherry scions. Methylome analysis showed that the sweet cherry genome presented 15.2~18.6%, 59.88~61.55%, 28.09~33.78%, and 2.99~5.28% methylation at total C, CG, CHG, and CHH sites, respectively. Shoot tips from dwarfing plants exhibited a hypermethylated pattern mostly due to increased CHH methylation, while leaves exhibited a hypomethylated pattern. According to GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis, DMGs (differentially methylated genes) and DEGs (differentially expressed genes) were enriched in hormone-related GO terms and KEGG pathways. Global correlation analysis between methylation and transcription revealed that mCpG in the gene body region enhanced gene expression and mCHH in the region near the TSS (transcription start site) was positively correlated with gene expression. Next, we found some hormone-related genes and TFs with significant changes in methylation and transcription, including SAURs, ARF, GA2ox, ABS1, bZIP, MYB, and NAC. This study presents a methylome map of the sweet cherry genome, revealed widespread DNA methylation alterations in scions caused by dwarfing rootstock, and obtained abundant genes with methylation and transcription alterations that are potentially involved in rootstock-induced growth changes in sweet cherry scions. Our findings can lay a good basis for further epigenetic studies on sweet cherry dwarfing and provide valuable new insight into understanding rootstock–scion interactions. Full article

Land plants grow throughout their life cycle via the continuous activity of stem cell reservoirs contained within their apical meristems. The shoot apical meristem (SAM) of Arabidopsis and other land plants responds to a variety of environmental cues, yet little is known about the response of meristems to seasonal changes in day length, or photoperiod. Here, the vegetative and reproductive growth of Arabidopsis wild-type and clavata3 (clv3) plants in different photoperiod conditions was analyzed. It was found that SAM size in wild-type Arabidopsis plants grown in long-day (LD) conditions gradually increased from embryonic to reproductive development. clv3 plants produced significantly more leaves as well as larger inflorescence meristems and more floral buds than wild-type plants in LD and short-day (SD) conditions, demonstrating that CLV3 signaling limits vegetative and inflorescence meristem activity in both photoperiods. The clv3 phenotypes were more severe in SDs, indicating a greater requirement for CLV3 restriction of SAM function when the days are short. In contrast, clv3 floral meristem size and carpel number were unchanged between LD and SD conditions, which shows that the photoperiod does not affect the regulation of floral meristem activity through the CLV3 pathway. This study reveals that CLV3 signaling specifically restricts vegetative and inflorescence meristem activity in both LD and SD photoperiods but plays a more prominent role during short days. Full article

Numerous biotechnological applications require a fast and efficient clonal propagation of whole plants under controlled laboratory conditions. For most plant species, the de novo regeneration of shoots from the cuttings of various plant organs can be obtained on nutrient media supplemented with plant hormones, auxin and cytokinin. While auxin is needed during the early stages of the process that include the establishment of pluripotent primordia and the subsequent acquisition of organogenic competence, cytokinin-supplemented media are required to induce these primordia to differentiate into developing shoots. The perception of cytokinin through the receptor ARABIDOPSIS HISTIDINE KINASE4 (AHK4) is crucial for the activation of the two main regulators of the establishment and maintenance of shoot apical meristems (SAMs): SHOOTMERISTEMLESS (STM) and the WUSCHEL-CLAVATA3 (WUS-CLV3) regulatory circuit. In this review, we summarize the current knowledge of the roles of the cytokinin signaling cascade in the perception and transduction of signals that are crucial for the de novo establishment of SAMs and lead to the desired biotechnological output—adventitious shoot multiplication. We highlight the functional differences between individual members of the multigene families involved in cytokinin signal transduction, and demonstrate how complex genetic regulation can be achieved through functional specialization of individual gene family members. Full article