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Journal of Microbiological Methods Jun 2024The ability to acquire three-dimensional (3D) information of cellular structures without the need for fluorescent tags or staining makes holotomographic imaging a...
The ability to acquire three-dimensional (3D) information of cellular structures without the need for fluorescent tags or staining makes holotomographic imaging a powerful tool in cellular biology. It provides valuable insights by measuring the refractive index (RI), an optical parameter describing the phase delay of light that passes through the living cell. Here, we demonstrate holotomographic imaging on industrial relevant ascomycete fungi and study their development and morphogenesis. This includes conidial germination, subcellular dynamics, and cytoplasmic flow during hyphal growth in Aspergillus niger. In addition, growth and budding of Aureobasidium pullulans cells are captured using holotomographic microscopy. Coupled to fluorescence imaging, lipid droplets, vacuoles, the mitochondrial network, and nuclei are targeted and analyzed in the 3D RI reconstructed images. While lipid droplets and vacuoles can be assigned to a specific RI pattern, mitochondria and nuclei were not pronounced. We show, that the lower sensitivity of RI measurements derives from the fungal cell wall that acts as an additional barrier for the illumination light of the microscope. After cell wall digest of hyphae and protoplast formation of A. niger expressing GFP-tagged histone H2A, location of nuclei could be determined by non-invasive RI measurements. Furthermore, we used coupled fluorescence microscopy to observe migration of nuclei in unperturbed hyphal segments and duplication during growth on a single-cell level. Detailed micromorphological studies in Saccharomyces cerevisiae and Trichoderma reesei are challenging due to cell size restrictions. Overall, holotomography opens up new avenues for exploring dynamic cellular processes in real time and enables the visualization of fungi from a new perspective.
PubMed: 38945304
DOI: 10.1016/j.mimet.2024.106983 -
Tree Physiology Jun 2024Stress tolerance in apple (Malus domestica) can be improved by grafting to a stress-tolerant rootstock, such as 'SH6' (Malus honanensis × M. domestica 'Ralls Genet')....
The transcription factor MhZAT10 enhances antioxidant capacity by directly activating the antioxidant genes MhMSD1, MhAPX3a, and MhCAT1 in apple rootstock SH6 (Malus honanensis × M. domestica).
Stress tolerance in apple (Malus domestica) can be improved by grafting to a stress-tolerant rootstock, such as 'SH6' (Malus honanensis × M. domestica 'Ralls Genet'). However, the mechanisms of stress tolerance in this rootstock are unclear. In Arabidopsis (Arabidopsis thaliana), the transcription factor ZINC FINGER OF ARABIDOPSIS THALIANA 10 (ZAT10) is a key component of plant tolerance to multiple abiotic stresses and positively regulates antioxidant enzymes. However, how reactive oxygen species (ROS) are eliminated upon activation of ZAT10 in response to abiotic stress remains elusive. Here, we report that MhZAT10 in the rootstock SH6 directly activates the transcription of three genes encoding the antioxidant enzymes MANGANESE SUPEROXIDE DISMUTASE 1 (MhMSD1), ASCORBATE PEROXIDASE 3A (MhAPX3a), and CATALASE 1 (MhCAT1) by binding to their promoters. Heterologous expression in Arabidopsis protoplasts showed that MhMSD1, MhAPX3a, and MhCAT1 localize in multiple subcellular compartments. Overexpressing MhMSD1, MhAPX3a, or MhCAT1 in SH6 fruit calli resulted in higher superoxide dismutase, ascorbate peroxidase, and catalase enzyme activities in their respective overexpressing calli than in those overexpressing MhZAT10. Notably, the calli overexpressing MhZAT10 exhibited better growth and lower ROS levels under simulated osmotic stress. Apple SH6 plants overexpressing MhZAT10 in their roots via Agrobacterium rhizogenes-mediated transformation also showed enhanced tolerance to osmotic stress, with higher leaf photosynthetic capacity, relative water content in roots, and antioxidant enzyme activity, as well as less ROS accumulation. Overall, our study demonstrates that the transcription factor MhZAT10 synergistically regulates the transcription of multiple antioxidant-related genes and elevates ROS detoxification.
PubMed: 38943359
DOI: 10.1093/treephys/tpae077 -
Viruses Jun 2024Disease resistance gene (R gene)-encoded nucleotide-binding leucine-rich repeat proteins (NLRs) are critical players in plant host defence mechanisms because of their...
Disease resistance gene (R gene)-encoded nucleotide-binding leucine-rich repeat proteins (NLRs) are critical players in plant host defence mechanisms because of their role as receptors that recognise pathogen effectors and trigger plant effector-triggered immunity (ETI). This study aimed to determine the putative role of a cassava coiled-coil (CC)-NLR (CNL) gene () (single allele) located on chromosome 12 in the tolerance or susceptibility to South African cassava mosaic virus (SACMV), one of the causal agents of cassava mosaic disease (CMD). A transient protoplast system was used to knock down the expression of by clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9). The -targeting CRISPR vectors and/or SACMV DNA A and DNA B infectious clones were used to transfect protoplasts isolated from leaf mesophyll cells from the SACMV-tolerant cassava () cultivar TME3. The CRISPR/Cas9 silencing vector significantly reduced expression in protoplasts whether with or without SACMV co-infection. Notably, SACMV DNA A replication was higher in protoplasts with lower expression levels than in non-silenced protoplasts. Mutagenesis studies revealed that protoplast co-transfection with CRISPR- silencing vector + SACMV and transfection with only SACMV induced nucleotide substitution mutations that led to altered amino acids in the highly conserved MHD motif of the -translated polypeptide. This may abolish or alter the regulatory role of the MHD motif in controlling R protein activity and could contribute to the increase in SACMV-DNA A accumulation observed in -silenced protoplasts. The results herein demonstrate for the first time a role for a CNL gene in tolerance to a geminivirus in TME3.
Topics: Manihot; Plant Diseases; Begomovirus; Virus Replication; Plant Proteins; Geminiviridae; CRISPR-Cas Systems; Disease Resistance; Protoplasts; Leucine-Rich Repeat Proteins
PubMed: 38932233
DOI: 10.3390/v16060941 -
Plants (Basel, Switzerland) Jun 2024Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major...
Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical roles in plant responses to various stresses. In this study, we found that , an gene from the soybean , showed drastic upregulation under drought stress. Subcellular localization experiments in tobacco epidermal cells and tobacco protoplasts showed that GmADF13 was localized in the nucleus and cytoplasm. We characterized its biological function in transgenic and hairy root composite soybean plants. plants transformed with displayed a more robust drought tolerance than wild-type plants, including having a higher seed germination rate, longer roots, and healthy leaves under drought conditions. Similarly, -overexpressing (OE) soybean plants generated via the -mediated transformation of the hairy roots showed an improved drought tolerance. Leaves from OE plants showed higher relative water, chlorophyll, and proline contents, had a higher antioxidant enzyme activity, and had decreased malondialdehyde, hydrogen peroxide, and superoxide anion levels compared to those of control plants. Furthermore, under drought stress, OE activated the transcription of several drought-stress-related genes, such as , , , , and . Thus, is a positive regulator of the drought stress response, and it may play an essential role in plant growth under drought stress conditions. These results provide new insights into the functional elucidation of soybean . They may be helpful for breeding new soybean cultivars with a strong drought tolerance and further understanding how help plants adapt to abiotic stress.
PubMed: 38931083
DOI: 10.3390/plants13121651 -
Pathogens (Basel, Switzerland) May 2024pv. () is a significant phytopathogen causing black rot disease in crucifers. Its virulence relies heavily on the type III secretion system (T3SS), facilitating...
pv. () is a significant phytopathogen causing black rot disease in crucifers. Its virulence relies heavily on the type III secretion system (T3SS), facilitating effector translocation into plant cells. The type III effectors (T3Es) disrupt cellular processes, promoting pathogen proliferation. However, only a few T3Es from have been thoroughly characterized. In this study, we further investigated two effectors using the T3Es-deficient mutant and the protoplast system. XopE2 triggers immune responses via an unidentified activator of the salicylic acid (SA) signaling pathway, whereas XopL suppresses the expression of genes associated with patterns-triggered immunity (PTI) and the SA signaling pathway. These two effectors exert opposing effects on immune responses. Additionally, we examined the relationship between the specific domains and functions of these two effector proteins. Our findings demonstrate that the N-myristoylation motif and N-terminal domain are essential for the subcellular localization and virulence of XopE2 and XopL, respectively. These novel insights enhance our understanding of the pathogenic mechanisms of T3Es and contribute to developing effective strategies for controlling bacterial disease.
PubMed: 38921746
DOI: 10.3390/pathogens13060448 -
Biosensors Jun 2024Plant cells' ability to withstand abiotic stress is strongly linked to modifications in their mechanical characteristics. Nevertheless, the lack of a workable method for...
Plant cells' ability to withstand abiotic stress is strongly linked to modifications in their mechanical characteristics. Nevertheless, the lack of a workable method for consistently tracking plant cells' mechanical properties severely restricts our comprehension of the mechanical alterations in plant cells under stress. In this study, we used the Double Resonator Piezoelectric Cytometry (DRPC) method to dynamically and non-invasively track changes in the surface stress (ΔS) generated and viscoelasticity (storage modulus G' and loss modulus G″) of protoplasts and suspension cells of rice under a drought stress of 5-25% PEG6000. The findings demonstrate that rice suspension cells and protoplasts react mechanically differently to 5-15% PEG6000 stress, implying distinct resistance mechanisms. However, neither of them can withstand 25% PEG6000 stress; they respond mechanically similarly to 25% PEG6000 stress. The results of DRPC are further corroborated by the morphological alterations of rice cells and protoplasts observed under an optical microscope. To sum up, the DRPC technique functions as a precise cellular mechanical sensor and offers novel research tools for the evaluation of plant cell adversity and differentiating between the mechanical reactions of cells and protoplasts under abiotic stress.
Topics: Oryza; Protoplasts; Polyethylene Glycols; Stress, Physiological; Droughts; Plant Cells
PubMed: 38920607
DOI: 10.3390/bios14060303 -
Horticulture Research Jan 2024CRISPR-Cas technologies allow for precise modifications in plant genomes and promise to revolutionize agriculture. These technologies depend on the delivery of editing...
CRISPR-Cas technologies allow for precise modifications in plant genomes and promise to revolutionize agriculture. These technologies depend on the delivery of editing components into plant cells and the regeneration of fully edited plants. In vegetatively propagated plants, such as grape, protoplast culture provides one of the best avenues for producing non-chimeric and transgene-free genome-edited plants. However, poor regeneration of plants from protoplasts has hindered their implementation for genome editing. Here, we report an efficient protocol for regenerating plants from protoplasts from multiple grape varieties. By encapsulating the protoplasts in calcium alginate beads and co-culturing them with feeder cultures, the protoplasts divide to form callus colonies that regenerate into embryos and ultimately plants. This protocol worked successfully in wine and table grape () varieties, as well as grape rootstocks and the grapevine wild relative . Moreover, by transfecting protoplasts with CRISPR-plasmid or ribonucleoprotein (RNP) complexes, we regenerated albino plants with edits in gene in three varieties and in . The results reveal the potential of this platform to facilitate genome editing in species.
PubMed: 38895602
DOI: 10.1093/hr/uhad266 -
International Journal of Molecular... May 2024Heavy metals are dangerous contaminants that constitute a threat to human health because they persist in soils and are easily transferred into the food chain, causing...
Heavy metals are dangerous contaminants that constitute a threat to human health because they persist in soils and are easily transferred into the food chain, causing damage to human health. Among heavy metals, nickel appears to be one of the most dangerous, being responsible for different disorders. Public health protection requires nickel detection in the environment and food chains. Biosensors represent simple, rapid, and sensitive methods for detecting nickel contamination. In this paper, we report on the setting up a whole-cell-based system, in which protoplasts, obtained from leaves, were used as transducers to detect the presence of heavy metal ions and, in particular, nickel ions. Protoplasts were genetically modified with a plasmid containing the reporter gene () under control of the promoter region of a sunflower gene coding for a small Heat Shock Protein (HSP). Using this device, the presence of heavy metal ions was detected. Thus, the possibility of using this whole-cell system as a novel tool to detect the presence of nickel ions in food matrices was assessed.
Topics: Nickel; Protoplasts; Nicotiana; Biosensing Techniques; Green Fluorescent Proteins; Food Contamination; Metals, Heavy
PubMed: 38892274
DOI: 10.3390/ijms25116090 -
International Journal of Molecular... May 2024Amino acid permeases (AAPs) transporters are crucial for the long-distance transport of amino acids in plants, from source to sink. While and rice have been extensively...
Amino acid permeases (AAPs) transporters are crucial for the long-distance transport of amino acids in plants, from source to sink. While and rice have been extensively studied, research on foxtail millet is limited. This study identified two transcripts of , both of which were induced by NO and showed similar expression patterns. The overexpression of and in inhibited plant growth and seed size, although SiAAP9 was found to transport more amino acids into seeds. Furthermore, transgenic showed increased tolerance to high concentrations of glutamate (Glu) and histidine (His). The high overexpression level of suggested its protein was not only located on the plasma membrane but potentially on other organelles, as well. Interestingly, sequence deletion reduced SiAAP9's sensitivity to Brefeldin A (BFA), and SiAAP9 had ectopic localization on the endoplasmic reticulum (ER). Protoplast amino acid uptake experiments indicated that SiAAP9 enhanced Glu transport into foxtail millet cells. Overall, the two transcripts of have similar functions, but SiAAP9L shows a higher colocalization with BFA compartments compared to SiAAP9S. Our research identifies a potential candidate gene for enhancing the nutritional quality of foxtail millet through breeding.
Topics: Arabidopsis; Plants, Genetically Modified; Gene Expression Regulation, Plant; Plant Proteins; Endoplasmic Reticulum; Seeds; Setaria Plant; Amino Acid Transport Systems; Protein Transport; Brefeldin A; Amino Acids; Glutamic Acid
PubMed: 38892028
DOI: 10.3390/ijms25115840 -
Nano Letters Jun 2024Tobacco mild green mosaic virus (TMGMV)-like nanocarriers were designed for gene delivery to plant cells. High aspect ratio TMGMVs were coated with a polycationic...
Tobacco mild green mosaic virus (TMGMV)-like nanocarriers were designed for gene delivery to plant cells. High aspect ratio TMGMVs were coated with a polycationic biopolymer, poly(allylamine) hydrochloride (PAH), to generate highly charged nanomaterials (TMGMV-PAH; 56.20 ± 4.7 mV) that efficiently load (1:6 TMGMV:DNA mass ratio) and deliver single-stranded and plasmid DNA to plant cells. The TMGMV-PAH were taken up through energy-independent mechanisms in protoplasts. TMGMV-PAH delivered a plasmid DNA encoding a green fluorescent protein (GFP) to the protoplast nucleus (70% viability), as evidenced by GFP expression using confocal microscopy and Western blot analysis. TMGMV-PAH were inactivated (iTMGMV-PAH) using UV cross-linking to prevent systemic infection in intact plants. Inactivated iTMGMV-PAH-mediated pDNA delivery and gene expression of GFP was determined using confocal microscopy and RT-qPCR. Virus-like nanocarrier-mediated gene delivery can act as a facile and biocompatible tool for advancing genetic engineering in plants.
PubMed: 38887996
DOI: 10.1021/acs.nanolett.3c04735