Search Results (230)

The short peptide AlaGluAspLeu (AEDL) stimulates shoot and root development in Nicotiana tabacum. Growing tobacco in the presence of AEDL was found to induce autophagy and programmed cell death, as demonstrated using immunodetection of the autophagy marker ATG8 and cytochrome c in the cytoplasm, as well as the detection of DNA breaks using the TUNEL assay. A detailed study of the ultrastructure of Nicotiana tabacum root cells grown in the presence of AEDL using transmission electron microscopy revealed fundamental structural differences from control cells. Control cells contained only lytic vacuoles, while in the presence of AEDL, tobacco root meristem cells contained predominantly protein-storing vacuoles and amyloplasts with numerous starch granules in the stroma. Characteristic types of phagophores were identified, forming numerous small autophagosomes with cytoplasmic regions, multivesicular bodies, or concentric membranes, possibly with cytoskeletal elements. Expression of autophagy protein genes revealed a decrease in TOR expression, which promoted autophagy activation and prevented ATG13 phosphorylation. ATG8 gene expression significantly increased in the presence of the AEDL peptide. Schematic diagrams of autophagy processes in root cells of control plants and those grown in the presence of AEDL are presented. Based on these data, it was concluded that stimulation of tobacco plant development in the presence of the AEDL peptide at a concentration of 10⁻⁷ M occurs due to the activation of metabolic processes and autophagy. Moreover, the synthesis of metabolites exceeds the required amount of nutrients, which accumulate in vacuoles and leucoplasts. Full article

Ethylparaben (EtP) is an emerging pollutant that is widely found in the environment, particularly in agricultural landscapes. With the extensive contamination of agricultural soils and irrigation waters, there is a rising concern about their potential impact on crop yields. To provide some of the first evidence that EtP may be more than just an agricultural contaminant, but a potential pollutant, we evaluated the systemic toxicities and cellular responses triggered by EtP in seed roots of Daucus carota, Lycopersicum esculentum, and Cucumis sativus, and in bulb roots of Allium cepa, at environmentally relevant concentrations of 1, 10, 100, and 1000 ng·L⁻¹. The seeds and bulbs remained in contact with the concentrations for 7 days. Distilled water and Tween 80 at 1000 ng·L⁻¹ were used as negative controls. The results were subjected to Kruskal–Wallis analysis of variance followed by Dunn’s test (p ≤ 0.05). In all plants, all concentrations significantly altered the activity of catalase, ascorbate peroxidase, guaiacol peroxidase, and superoxide dismutase. In carrot (10, 100, and 1000 ng·L⁻¹), tomato (1000 ng·L⁻¹), and cucumber (all concentrations), such concentrations caused lipid peroxidation, leading to the accumulation of hydrogen peroxide, as well as hydroxyl and superoxide radicals in the cells. These oxidants caused a delay in the progression of the cell cycle and alterations to the mitotic spindle in the root meristems, significantly inhibiting root growth in the plants evaluated. Recurrent contamination with EtP can potentially harm soil quality, posing a risk to both agricultural productivity and the environment. Full article

Regulatory changes in the EU for safety purposes require strict control and high safety standards for essential oils obtained by steam distillation, as they are classified as chemical mixtures with potential toxic effects. Subcritical water extracts (SWEs) are considered safer. This study evaluated the cytotoxicity and genotoxicity of SWEs from Rosa damascena Mill. and Rosa alba L. in three test systems at different hierarchical levels: higher plants (root meristems of Hordeum vulgare), somatic cells of Mus musculus ICR strain, and human lymphocytes in vitro. The chromatographic fingerprint of the extracts revealed the presence of key components such as flavonoids, phenolic acids, and glycoside derivatives, with species-dependent variations and concentrations. No significant cytotoxicity was detected in the concentration range of 6–20%. SWE from R. alba showed a higher level of safety at high doses. Genotoxicity tests showed a weak, dose-dependent induction of chromosomal aberrations and micronuclei in barley and lymphocytes (greater in R. alba), a lack of genotoxicity in mouse bone marrow, and a slight increase in micronuclei in mouse erythrocytes after exposure to R. alba extract. The results highlight the suitability of SWEs from R. damascena and R. alba for safe application in the medical, food, and cosmetic industries. Full article

On acid soils, aluminum (Al³⁺) is typically toxic to plants, though certain species like Pogostemon cablin (patchouli) show growth stimulation. This study reveals that Al functions as a root development stimulant in patchouli under acidic conditions. Treatment with 1.0 mM AlCl₃ for 34 days significantly enhanced root architecture, increasing total root length by 172.12% and root dry weight by 161.75%, without affecting shoot biomass. Structural analysis showed Al accumulation in root tip meristems and lateral root primordia, triggering a 103.77% increase in meristem activity and a 111.9% promotion of cell elongation. Physiological assays showed that Al treatment reduced H₂O₂ and malondialdehyde (MDA) levels by 49.2% and 67.6%, respectively, while boosting glutathione (GSH) content by 187.5%, thereby mitigating oxidative membrane damage mainly through the non-enzymatic antioxidant system. Moreover, Al deprivation impaired lateral root elongation, highlighting its functional importance. Gene expression profiling further indicated that Al regulated pathways related to cell proliferation, cell wall remodeling, and lateral root development. Taken together, our findings uncover a novel mechanism by which Al, traditionally regarded as toxic, acts as a stimulator of root development in patchouli, providing new insights into the molecular networks underlying plant abiotic stress responses. Full article

Sulfur metabolism plays an important role in plant growth and environmental adaptation. Sulfate transporters (SULTRs) are essential players that mediate sulfur acquisition and distribution in many plants, thereby influencing the cellular redox homeostasis under abiotic stress. In this study, we identified 16 putative HvSULTRs genes in barley at the genome-wide level. The conservation and divergence of the SULTR gene family were assessed through a phylogenetic tree and gene structure analysis, revealing that these genes are closely distributed along the chromosomes. Furthermore, the expression pattern of SULTRs in multiple tissues, including flower, root, leaf, stem, seeds, female, male, root meristem, and apical meristem, were analyzed among ten land plants using a public database. Interestingly, the expression of HvSULTR2, HvSULTR4, and HvSULTR5 was upregulated after four days of heat treatment, suggesting their importance in barley’s adaptive response to heat stress. In addition, HvSULTR11 was confirmed to be localized at the plasma membrane and display functional interactions with Hv14-3-3A/Hv14-3-3D. In addition, haplotypes of the HvSULTR11 based on SNP (Single Nucleotide Polymorphism) were divided into ten types across 123 barley varieties. Together, these results provide a new clue to clarify the molecular mechanism of SULTRs in stress response and a new candidate gene resource to enhance the stress (e.g., heat and drought) tolerance in barley. Full article

The root system is an important determinant affecting the growth, adaptivity and stress resistance of citrus plants. Currently, the genetic regulatory network underlying root growth and development in citrus remains largely unknown. We report that a PtrAUX/IAA-ARF complex mediates the growth and development of roots in citrus through regulating the transcription of PtrSAUR. The auxin signaling pathway plays an essential role in regulating the growth and development of roots. In this study, we found that in citrus Poncirus trifoliata, PtrIAA12, encoding a canonical Aux/IAA protein, was highly expressed in the meristem and elongation zone of the root. Functional characterization showed that overexpression and silence of PtrIAA12 significantly enhanced and suppressed the elongation of primary roots, respectively. Further analysis revealed that PtrIAA12 could interact with some members of PtrARFs, of which, PtrARF8 was identified to be the transcriptional factor of PtrSAUR17. Investigation of PtrSAUR17 transgenic plants verified that PtrSAUR17 is a key gene regulating the growth of roots in citrus. In conclusion, PtrIAA12 and PtrARF8 are the key members of the AUX/IAA-ARF complex in citrus controlling the growth and development of roots through regulating the transcription of PtrSAUR17. Full article

Non-CG DNA methylation plays a critical role in regulating root development and stress responses in Arabidopsis thaliana under cadmium (Cd²⁺) exposure. We compared wild type (WT) plants with the ddc triple mutant (deficient in DRM1, DRM2, and CMT3) to assess how epigenetic modifications affect the root apical meristem (RAM) under 100 µM and 150 µM CdCl₂ treatments. Cd²⁺ exposure led to RAM disorganization, reduced cortical cell number, and quiescent center (QC) cell loss in WT roots, while ddc mutants maintained meristem integrity and exhibited QC cell expansion. Auxin signaling, assessed via pDR5::GFP, was disrupted in WT roots at high Cd²⁺ levels but remained stable in ddc mutants. Similarly, WT roots showed elevated reactive oxygen species accumulation under stress, whereas ddc mutants displayed a reduced oxidative response. These results suggest that non-CG DNA methylation suppresses key regulators of stem cell maintenance, hormonal balance, and redox homeostasis during heavy metal stress. Loss of this methylation in the ddc mutant confers enhanced resilience to Cd²⁺ toxicity, highlighting an epigenetic mechanism underlying root stress adaptation. Full article

We investigated the effect of Agrobacterium rhizogenes-mediated transformation mof rolB on adventitious root development and endogenous hormones in ‘duli’ (Pyrus betulaefolia) via transcriptomic analysis of wild-type (WT) and rolB-transformed plants. The formation of root primordia occurred earlier in transgenic ‘duli’ than in the WT plants. At seven days, 57% of the transgenic seedlings had formed root primordia, whereas root primordia first appeared at seven days in WT ‘duli’. The rooting rate of transgenic ‘duli’ and WT plants was 90% and 77.14%, respectively. rolB significantly promoted the formation of secondary roots. Within 20 days, auxin (IAA), gibberellic acid (GA₃), and zeatin riboside (ZR) were higher and abscisic acid (ABA) was lower in transgenic ‘duli’ than in WT plants. Gene Ontology analysis revealed high enrichment in signaling pathways and ADP binding, and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that several differentially expressed genes were enriched in flavonoid and carotenoid-related pathways and plant hormone signal transduction. rolB induced changes in the expression patterns of several genes involved in hormone biosynthesis, metabolism, and signal transduction pathways in ‘duli’. Weighted gene co-expression network analysis identified the DEGs associated with endogenous hormone levels and indicated that the central genes of modules most strongly correlated with ABA, ZR, IAA, and GA₃ regulate protein synthesis, signaling, and root tissue meristem activity. Protein–protein interaction analysis yielded a co-expression network of physiological and transcriptomic data during rooting and identified key genes at the network core. These findings provide valuable insights into the regulatory mechanisms of rolB and its influence on root development in ‘duli’. Full article

Sweet basil (Ocimum basilicum L.) is one of the most well-known aromatic herbs, which are economically important for food and pharmaceutical purposes. In vitro regeneration protocols are a fundamental part of molecular approaches, such as genome editing, which are used to enhance crop quality and pathogen resistance. In this research, in vitro regeneration methods were developed to examine the morphogenic aptitude of four different explant types from five commercial cvs of Ocimum basilicum L. (‘Prospera’, ‘Paoletto’, ‘Italiko FT’, ‘Dark opal’, and ‘Bolloso napoletano’). ‘Prospera’ showed the highest direct regeneration efficiency in all of the explant types (100% in the roots, 36% ± 0.02 in the cotyledons, 7.5% ± 0.2 in the hypocotyls, and 50% ± 0.04 in the cotyledonary nodes). The roots were found to be the most effective explant type, producing nodule-like meristems (100% in ‘Prospera’ and ‘FT Italiko’, 95.24% ± 0.01 in ‘Bolloso napoletano’), as precursors of shoots. Histological analysis was confirmed to be a suitable method to detect meristematic activity during the early morphogenic process and to evaluate the explants’ regeneration potential. Full article

Background: Transcription factors (TFs) critically regulate gene expression, orchestrating plant growth, development, and stress responses. The conserved IDD (INDETERMINATE DOMAIN) TF family modulates key developmental processes, including root, stem, and seed morphogenesis. Dendrocalamus latiflorus Munro, an economically vital sympodial bamboo in southern China, suffers significant yield losses due to prevalent bamboo shoot abortion, impacting both edible shoot production and timber output. Despite the documented roles of IDD TFs in shoot apical meristem expression and lateral organ regulation, their genome-wide characterization in D. latiflorus remains unstudied. Methods: Using IDD members from Arabidopsis thaliana, Oryza sativa, and Phyllostachys edulis as references, we identified 45 DlIDD genes in D. latiflorus. Comprehensive bioinformatics analyses included gene characterization, protein physicochemical assessment, phylogenetic reconstruction, and examination of gene structures/conserved domains. Differential expression of DlIDD genes was profiled between dormant and sprouting bamboo shoots to infer putative functions. Results: The 45 DlIDD genes were phylogenetically classified into three subfamilies and unevenly distributed across 34 chromosomes. Whole-genome duplication (WGD) events drove the expansion of this gene family. Promoter analyses revealed enriched cis-regulatory elements associated with hormone response and developmental regulation. Functional analyses suggested potential roles for DlIDD genes in bamboo shoot development. Conclusions: This study provides a foundation for future research to elucidate the functions of IDD TFs and their regulatory mechanisms in bamboo shoot morphogenesis and lateral bud development within woody monocots. Full article

The AP2/ERF transcription factor family plays a vital role in regulating rice growth and development. Recent years have seen notable progress in understanding the functions of AP2/ERF transcription factors in rice. Studies indicate that these factors not only control the differentiation of rice inflorescence meristems but also participate in developing organs such as roots, stems, and leaves. However, the specific molecular mechanisms of AP2/ERF transcription factors, their interactions with other proteins, and how they precisely regulate the expression of particular genes still require further research. This paper systematically reviews recent advances in the functional studies of AP2/ERF transcription factors in rice growth and development, focusing on their roles in inflorescence development, grain formation, and the development of roots, stems, and leaves. It also discusses their potential applications in molecular breeding. By compiling recent research findings, this review aims to provide both theoretical insights and practical guidance for a better understanding of the regulatory networks involving AP2/ERF transcription factors and their use in rice genetic improvement. Full article

The growth and yield of the aboveground parts of maize (Zea mays L.) are closely associated with development of the root system. LBD (Lateral Organ Boundaries Domain) transcription factors are crucial for the regulation of lateral organ development in plants. However, to date, little information has been uncovered about the LBD gene family in maize. In this research, a genome-wide identification revealed 45 LBD gene members in maize. The subsequent phylogeny, structure, and profiles of expression were analyzed. These genes were found to be dispersed across all 10 maize chromosomes and expressed in diverse tissues, including the roots, leaves, stems, pericarp, and vegetative meristems. Notably, ZmLBD12 exhibited specific expression in roots. Subsequent over-expression of ZmLBD12 in Arabidopsis thaliana demonstrated its role in lateral root development, identifying it as a candidate gene for further investigation of root development in maize. Our findings provide a systematic analysis of ZmLBD genes and highlight ZmLBD12 as a potential target gene for developing high-yielding, lodging-resistant maize varieties. Full article

In this study, the effect of growth regulators on shoot proliferation and rooting were evaluated to develop an efficient micropropagation protocol for the Cannabis sativa L. cultivars ‘Cherry Soda’ and ‘Purple’. Apical meristems were isolated from actively growing shoots of stock plants and transferred to Driver and Kuniyuki Walnut (DKW) culture medium containing either 0.0, 0.5, 1.0, 2.0, or 5.0 μM meta-Topolin to study their shoot proliferation response. Resulting shoot cultures were transferred to medium containing varying levels of Indole Acetic Acid (IAA), Indole Butyric Acid (IBA), or Naphthalene Acetic Acid (NAA), solely or in combination, and were subjected to a 10-day dark incubation followed by a 16 h/8 h light/dark period to identify the best treatment for root production. Among the different shoot proliferation treatments studied, the maximum number of shoots was produced on the control medium that was devoid of any meta-Topolin. Cultures grown on medium containing 5.0 μM meta-Topolin exhibited hyperhydricity, where shoots appeared translucent and pale green in color; were characterized by water-soaked lesions; and leaves appeared curled and brittle in contrast to healthy looking cultures. Among the various rooting treatments studied, shoots grown in the dark for 10 days exhibited the highest frequency of rooting on medium containing 4.0 μM NAA or 6.0 μM IBA + 1.0 μM NAA. Full developed plants with a robust shoot and root system were transferred to soil, acclimatized under conditions for high humidity, and then transferred to ambient conditions in 4 weeks. The micropropagation protocol developed here allows for rapid multiplication of disease-free plants in C. sativa cultivars. Full article

The capacity of plants to generate new organs and tissues throughout their life cycle depends on the activity of the stem cells contained in meristematic tissues. Plant stem cells are organized in small, clustered populations referred to as stem cell niches. In addition to generating new undifferentiated cells, stem cell niches also provide the positional information that maintains stem cell self-renewal properties and controls the non-cell-autonomous differentiation of surrounding tissues. In this review, we aim to analyze and discuss the most recent literature describing the molecular mechanism controlling the activity and the organization of the stem cell niche in the root of the model plant Arabidopsis thaliana (L.) Heynh. In particular, we will focus on the complex molecular regulatory networks that control the balance between stemness and differentiation in distal stem cells, as well as the maintenance of the mitotically inactive state of the quiescent center. Full article

Human activities are increasing the occurrence of megafires that alter ecological dynamics in forest ecosystems. The objective of this study was to understand the impacts of a 610 km² megafire on patterns of tree regeneration and herbivory across three forest types (aspen/fir, oak/maple, and pinyon/juniper). Seventeen transect pairs in adjacent burned/unburned forest stands (6 aspen/fir, 5 oak/maple, and 6 pinyon/juniper) were measured. Sapling density, meristem removal, and height were measured across the transect network over a three-year period from 2019 to 2021. Tree species able to resprout from surviving roots (oak and aspen) generally responded positively to fire while species that typically regenerate by seeding showed little post-fire regeneration. Browse pressure was concentrated on deciduous tree species and was greater in burned areas but the effect diminished over the three-year study period. Meristem removal by herbivores was below the critical threshold, resulting in vertical growth over time. Our results indicate that forest regeneration within the megafire scar was generally positive and experienced sustainable levels of ungulate browsing that were likely to result in forest recruitment success. Full article