Protoplasma最新文献

Mutation of MEDIATOR 18 leads to death of highly proliferating cells within the Arabidopsis root apical meristem, which impairs root growth. Phosphate (Pi) is a macronutrient required to support mitotic activity in meristems, and its deficiency causes root growth inhibition; thus, we hypothesized that Pi availability could influence cell viability as well. With this in mind, in vitro experiments were performed varying the Pi concentration (0, 1, 10, and 250 µM) in the growth medium of Arabidopsis WT seedlings and med18-1 mutants to analyze meristem integrity and root hair development and correlate it with gene expression of selected promoter-reporter gene fusions. We found that WT (Col-0) seedlings entered the already reported determinate root growth program that terminates mitosis and differentiates primary root meristems at low (0, 1, and 10 µM) Pi concentrations. Unexpectedly, in marked contrast to the WT, med18-1 null mutant seedlings had healthy meristems under low Pi availability, and the cell death occurred only at high Pi (250 µM Pi). Root hair density and length were greater in med18-1 mutants than WT at all Pi concentrations tested. Gene expression analyses for cell cycle, auxin, and damage response as well as detection of hydrogen peroxide indicated that MED18 promotes the transit from cell division into differentiation of primary root tips induced by Pi starvation but protects the root meristem from genotoxic stress upon zeocin application. These results uncover an unexpected finding in which the lack of an essential macronutrient decreases the genotoxic pressure to highly proliferating plant cells.

The antioxidant defense mechanisms that shield eukaryotes from oxidative stress depend heavily on the enzyme catalase (CAT). These proteins, which are found in nearly all living creatures, perform crucial functions in regulating how plants react to biotic and abiotic stimuli by regulating the breakdown of H₂O₂. CAT is encoded by a small gene family in plants. In the current study, the first catalase gene from oat (Avena sativa L.) designated AsCAT1 was isolated and characterized. The corresponding AsCAT1 protein has 492 amino acids and presented a significant similarity with other catalase proteins in subfamily 1, according to phylogenetic study. A peroxisomal targeting signature (PTS1), as shown for other catalase proteins, is present at the C-terminal portion of AsCAT1 which confers a peroxisomal localization of this protein. AsCAT1 protein has a catalytic activity that could be stimulated by different cations. The expression of AsCAT1 protein in bacterial cells conferred tolerance to some abiotic stresses (NaCl, sorbitol, and LiCl). AsCAT1 is highly expressed in leaves, but its expression is low in roots as previously shown for other monocotyledonous plants. Interestingly, AsCAT1 gene expression is upregulated in response to a variety of stimuli, including hormonal, osmotic, salt, and heavy metal exposures. Our data strongly suggest that AsCAT1 is a crucial gene implicated in oat to aid this species in fending off environmental challenges. Such results help in further understanding the functions of catalase proteins in monocotyledonous plants in general and oat in particular.

Jasmonates are important plant hormones widely involved in processes such as plant growth and stress responses. However, the effects of jasmonic acid on the growth, development, and quality formation in carrots (Daucus carota L.) are less frequently reported. In this study, treatments of 100 µmol/L methyl jasmonate (MeJA), 200 µmol/L MeJA, and 10 mmol/L sodium diethyldithiocarbamate (DIECA) were established, with water serving as the control group, to investigate the effects of different concentrations of MeJA and its inhibitor DIECA on carrot growth and development, fleshy root structure, and the accumulation of lignin and carotenoids. Compared to the control, MeJA treatment significantly increased the number of xylem vessels in the carrot fleshy root, with thickened cell walls, enhanced lignin-related enzyme activities, and well-developed xylem. Different concentrations of MeJA promoted the accumulation of both lignin and carotenoids in carrots, whereas DIECA treatment did the opposite. Gene expression analysis indicated that MeJA altered the transcript levels of genes in carotenoid and lignin metabolism. The research findings in this paper would provide new insights into jasmonic acid-mediated carrot root development and quality formation.

Physcomitrium patens (formerly Physcomitrella patens), a model moss species, has emerged as an invaluable system for studying autophagy in plants. This review highlights the unique advantages of P. patens for autophagy research, including its efficient homologous recombination in mitotic cells, simple body plan, haploid-presiding life cycle, and accessibility to microscopic observation. I discuss recent advances in understanding autophagy mechanisms in P. patens, particularly focusing on the role of core autophagy-related (ATG) genes in growth, development, stress responses, and cell death. The characterization of autophagy-deficient mutants revealed unexpected roles of autophagy in promoting cell death under oxidative stress and desiccation, in contrast with classical survival functions. I also examine the conservation and divergence of the autophagy machinery between mosses and vascular plants, emphasizing how P. patens bridges evolutionary gaps in our understanding of plant autophagy. Finally, I outline future perspectives on the use of this model system to address fundamental questions about selective autophagy, autophagosome dynamics, and the integration of autophagy with developmental programs.

The paper presents unknown ultrastructure observed by scanning electron microscope (SEM) of aedeagus, spermatheca and body morphology of Psylliodes valida Weise, 1889 (Coleoptera: Chrysomelidae: Galerucinae) from Türkiye. This species, which belongs to one of the genera that is very important in biological control, is a new record for Çorum province and the Central Anatolia Region, where it was collected in August 2023.The genus Psylliodes Latreille includes 200 species in the worldwide, while it is represented by 42 species in Türkiye. As known, aedeagus, spermatheca and body morphology are taxonomically important structures. However, before the present study, the structural morphology of these features in Psylliodes Latreille had not been addressed in any previous research, leaving a notable gap in the literature For this reason, ultrastructural and detailed investigations of aedeagus, spermatheca and body morphology of Psylliodes Latreille from Türkiye were firstly studied with SEM to contain male and female genital descriptions of Psylliodes valida Weise, 1889. Photos in SEM are also given in the text.

Understanding protein-protein interactions (PPIs) in planta is essential for deciphering the molecular mechanisms underlying plant development and responses to environmental stresses. Here, we demonstrate the application of the split firefly luciferase complementation assay (SplitLUC) using a cooled charge-coupled device (CCD)-based plant imaging system and a microplate reader to detect and quantify PPIs in planta. As an example, we investigated the previously reported interaction between DET1- and DDB1-ASSOCIATED 1 (DDA1), a component of the CULLIN4 (CUL4)-E3 ubiquitin ligase complex, and PYR1-like 8 (PYL8), a known substrate of the same complex. Co-infiltration of Agrobacterium strains carrying DDA1-nLUC and cLUC-PYL8 constructs resulted in a robust luminescent signal upon addition of D-luciferin, which was visualised and quantified using the NightSHADE evo Plant Imaging System. Control combinations lacking either fusion partner or containing only empty vectors did not produce detectable luminescence, confirming the specificity of the interaction. To account for infiltration efficiency and variability in transgene expression, the luminescence values were normalised against fluorescence from co-infiltrated TagRFP, measured using a Tecan Spark microplate reader. This normalisation strategy effectively mitigated leaf-to-leaf variation in luminescence signals and demonstrated that the SplitLUC assay, when combined with fluorescence-based normalisation, provides a robust and reliable quantitative method for studying PPIs in planta. We propose that this approach is well-suited for investigating weaker interactions, assessing the influence of additional (bridge) proteins, and mapping interaction domains within the proteins of interest.

This research represents the first comprehensive biochemical analysis of mature fruits from apple trees of the Chloromeles section, specifically examining Malus coronaria, Malus ioensis, Malus × platycarpa and Malus × soulardii. The experimental investigations revealed distinctive compositional characteristics in lipids, carbohydrates, flavonoids, and chlorophylls that markedly differentiate these species from other representatives of the genus Malus. Specifically, our research revealed the absence of procyanidin B1 and a high content of chlorogenic acid, accompanied by remarkably low quantities of cinnamic acid and its derivatives. Linoleic acid represented approximately 50% of the total fatty acid profile, which is substantially lower compared to the lipid content commonly observed in domesticated apple varieties. Conversely, the linolenic acid concentration was significantly higher. Fructose levels in fruit tissues of the Chloromeles section ranged from 15% in M. ioensis to 50% in M. coronaria, the section's largest fruiting species. Additionally, the analysis revealed the presence of transport sugars and highly etherified protopectins. Unlike other Malus, the Chloromeles section mature fruits exhibited high chlorophyll and low carotenoid contents. These pigments were present in both the peel and pulp tissues. The observed composition, including elevated transport sugar and protopectin levels, is typically associated with fruits at early ripening stages. This may contribute to the suboptimal flavor development, despite the presence of a relatively high total soluble sugar content.

The Tumour Protein D52 (TPD52) family, including TPD52, TPD52L1, and TPD52L2, plays critical roles in membrane trafficking, lipid metabolism, and oncogenic signalling, with its overexpression linked to multiple cancers. Phosphorylation is a key regulator of their functions, yet their phosphoproteomic landscape remains underexplored. This study integrates over 3,825 public human phosphoproteomic datasets to map phosphorylation profiles of TPD52, TPD52L1, and TPD52L2, identifying dominant phosphosites like S171, S176, S149, and S12, S166 within conserved coiled-coil and PEST-like domains. CAMK2D was identified as a predominant shared kinase, alongside CDK2 and GRK5, associating these modifications with calcium signaling, cell cycle progression, and cytoskeletal remodeling. Co-phosphoregulation highlighted positive interactions with ABRAXAS2 and negative correlations with ABLIM3, implicating involvement in ubiquitin-mediated degradation, epithelial-mesenchymal transition (EMT), and cytokinesis. Notably, hypophosphorylation at TPD52_S171/S176 was observed in hepatocellular and lung carcinomas, whereas hyperphosphorylation at TPD52L2_S166 prevailed in ovarian and pancreatic cancers, underscoring biomarker utility. Phosphorylation-driven interactomes emphasized roles in vesicular trafficking and oncogenesis This study catalogues the phosphorylation events and explores the potential of TPD52 family as a phosphoregulated hub in cancer biology, with CAMK2D as a potential therapeutic target.