Brassinosteroids (BR) are steroidal phytohormones essential for plant growth, development, and stress resistance. They fulfil this role partially by modulating cell wall structure and composition through the control of gene expression involved in primary and secondary cell wall biosynthesis and metabolism. This affects the deposition of cellulose, lignin, and other components, and modifies the inner architecture of the wall, allowing it to adapt to the developmental status and environmental conditions.
View Article and Find Full Text PDFEndoplasmic reticulum-plasma membrane contact sites (ER-PM CSs) are evolutionarily conserved membrane domains found in all eukaryotes, where the ER closely interfaces with the PM. This short distance is achieved in plants through the action of tether proteins such as synaptotagmins (SYTs). Arabidopsis comprises five SYT members (SYT1-SYT5), but whether they possess overlapping or distinct biological functions remains elusive.
View Article and Find Full Text PDFBiological membranes play a crucial role in actively hosting, modulating and coordinating a wide range of molecular events essential for cellular function. Membranes are organized into diverse domains giving rise to dynamic molecular patchworks. However, the very definition of membrane domains has been the subject of continuous debate.
View Article and Find Full Text PDFPlant synaptotagmins (SYTs) are resident proteins of the endoplasmic reticulum (ER). They are characterized by an N-terminal transmembrane region and C2 domains at the C-terminus, which tether the ER to the plasma membrane (PM). In addition to their tethering role, SYTs contain a lipid-harboring SMP domain, essential for shuttling lipids between the ER and the PM.
View Article and Find Full Text PDFControlled primary cell wall remodeling allows plant growth under stressful conditions, but how these changes are conveyed to adjust cellulose synthesis is not understood. Here, we identify the TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins as new members of the cellulose synthase complex (CSC) and describe their unique and hitherto unknown dynamic association with the CSC under cellulose-deficient conditions. We find that TTLs are essential for maintaining cellulose synthesis under high-salinity conditions, establishing a stress-resilient cortical microtubule array, and stabilizing CSCs at the plasma membrane.
View Article and Find Full Text PDFPurpose: Ultralow-field (ULF) point-of-care MRI systems allow image acquisition without interrupting medical provision, with neonatal clinical care being an important potential application. The ability to measure neonatal brain tissue T is a key enabling technology for subsequent structural image contrast optimization, as well as being a potential biomarker for brain development. Here we describe an optimized strategy for neonatal T mapping at ULF.
View Article and Find Full Text PDFBrassinosteroids (BRs) play key roles in diverse plant growth processes through a complex signaling pathway. Components orchestrating the BR signaling pathway include receptors such as kinases, transcription factors, protein kinases and phosphatases. The proper functioning of the receptor kinase BRI1 and the transcription factors BES1/BZR1 depends on their dephosphorylation by type 2A protein phosphatases (PP2A).
View Article and Find Full Text PDFIn this glossary of plant cell structures, we asked experts to summarize a present-day view of plant organelles and structures, including a discussion of outstanding questions. In the following short reviews, the authors discuss the complexities of the plant cell endomembrane system, exciting connections between organelles, novel insights into peroxisome structure and function, dynamics of mitochondria, and the mysteries that need to be unlocked from the plant cell wall. These discussions are focused through a lens of new microscopy techniques.
View Article and Find Full Text PDFAutophagy is a catabolic and recycling pathway that maintains cellular homeostasis under normal growth and stress conditions. Two major types of autophagy, microautophagy and macroautophagy, have been described in plants. During macroautophagy, cellular content is engulfed by a double-membrane vesicle called autophagosome.
View Article and Find Full Text PDFNon-vesicular lipid transfer at ER and plasma membrane (PM) contact sites (CS) is crucial for the maintenance of membrane lipid homeostasis. Extended synaptotagmins (E-Syts) play a central role in this process as they act as molecular tethers of ER and PM and as lipid transfer proteins between these organelles. E-Syts are proteins constitutively anchored to the ER through an N-terminal hydrophobic segment and bind the PM via a variable number of C-terminal C2 domains.
View Article and Find Full Text PDFEndoplasmic reticulum-plasma membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased PM integrity under multiple abiotic stresses, such as freezing, high salt, osmotic stress, and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity.
View Article and Find Full Text PDFThe enzymes involved in l-ascorbate biosynthesis in photosynthetic organisms (the Smirnoff-Wheeler [SW] pathway) are well established. Here, we analyzed their subcellular localizations and potential physical interactions and assessed their role in the control of ascorbate synthesis. Transient expression of C terminal-tagged fusions of SW genes in Nicotiana benthamiana and Arabidopsis thaliana mutants complemented with genomic constructs showed that while GDP-d-mannose epimerase is cytosolic, all the enzymes from GDP-d-mannose pyrophosphorylase (GMP) to l-galactose dehydrogenase (l-GalDH) show a dual cytosolic/nuclear localization.
View Article and Find Full Text PDFIn contrast to climacteric fruits such as tomato, the knowledge on key regulatory genes controlling the ripening of strawberry, a nonclimacteric fruit, is still limited. NAC transcription factors (TFs) mediate different developmental processes in plants. Here, we identified and characterized Ripening Inducing Factor (FaRIF), a NAC TF that is highly expressed and induced in strawberry receptacles during ripening.
View Article and Find Full Text PDFMutations in the Arabidopsis () gene cause reduced tolerance to osmotic stress evidenced by an arrest in root growth and root swelling, which makes it an interesting model to explore how root growth is controlled under stress conditions. We found that osmotic stress reduced the growth rate of the primary root by inhibiting the cell elongation in the elongation zone followed by a reduction in the number of cortical cells in the proximal meristem. We then studied the stiffness of epidermal cell walls in the root elongation zone of mutants under osmotic stress using atomic force microscopy.
View Article and Find Full Text PDFThe theory of evolution is one of the greatest scientific achievements in the intellectual history of humankind, yet it is still contentious within certain social groups. Despite being as robust and evidence-based as any other notable scientific theory, some people show a strong reluctance to accept it. In this study, we used the Measure of Acceptance of the Theory of Evolution (MATE) and Knowledge of Evolution Exam (KEE) questionnaires with university students from four academic degree programs (Chemistry, English, History, and Biology) of ten universities from Spain to measure, respectively, acceptance and knowledge of evolutionary theory among third-year undergraduate students (nMATE = 978; nKEE = 981).
View Article and Find Full Text PDFThe aim of this work was to study the sexual dimorphism of the occlusal surface of the maxillary postcanine dentition using geometric morphometric techniques. This study evaluated 139 individuals as part of five osteological collections from municipal cemeteries in the province of Granada (Spain). The landmarks and semilandmarks were analysed by principal components analysis, canonical variate analysis and discriminant analysis.
View Article and Find Full Text PDFJ Exp Bot
July 2020
In plant cells, environmental stressors promote changes in connectivity between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM). Although this process is tightly regulated in space and time, the molecular signals and structural components mediating these changes in interorganelle communication are only starting to be characterized. In this report, we confirm the presence of a putative tethering complex containing the synaptotagmins 1 and 5 (SYT1 and SYT5) and the Ca2+- and lipid-binding protein 1 (CLB1/SYT7).
View Article and Find Full Text PDFFaMADS9 is the strawberry (Fragaria x ananassa) gene that exhibits the highest homology to the tomato (Solanum lycopersicum) RIN gene. Transgenic lines were obtained in which FaMADS9 was silenced. The fruits of these lines did not show differences in basic parameters, such as fruit firmness or colour, but exhibited lower Brix values in three of the four independent lines.
View Article and Find Full Text PDFDespite the high mortality that have been associated with pregnancy and childbirth in past populations, few cases of the remains of pregnant women burials are described in the bioarchaeological reports. This paper is focused on the case of a double inhumation found in the Medieval Muslim Necropolis (11 to 15 centuries) of in Granada (Spain). A complete skeleton of a woman and the skeletal remains of a full-term fetus located under the mother's left femur, were discovered in this burial.
View Article and Find Full Text PDFOne of the most important adaptations of seagrasses during sea colonization was the capacity to grow at the low micromolar nitrate concentrations present in the sea. In contrast to terrestrial plants that use H symporters for high-affinity NO uptake, seagrasses such as L. use a Na-dependent high-affinity nitrate transporter.
View Article and Find Full Text PDFBrassinosteroids (BRs) form a group of steroidal hormones essential for plant growth, development, and stress responses. BRs are perceived extracellularly by plasma membrane receptor-like kinases that activate an interconnected signal transduction cascade, leading to the transcriptional regulation of BR-responsive genes. () genes are specific for land plants, and their encoded proteins are defined by the presence of protein-protein interaction motives, that is, an intrinsic disordered region at the N terminus, six tetratricopeptide repeat domains, and a C terminus with homology to thioredoxins.
View Article and Find Full Text PDFThroughout evolution, a number of animals including humans have lost the ability to synthesize ascorbic acid (ascorbate, vitamin C), an essential molecule in the physiology of animals and plants. In addition to its main role as an antioxidant and cofactor in redox reactions, recent reports have shown an important role of ascorbate in the activation of epigenetic mechanisms controlling cell differentiation, dysregulation of which can lead to the development of certain types of cancer. Although fruits and vegetables constitute the main source of ascorbate in the human diet, rising its content has not been a major breeding goal, despite the large inter- and intraspecific variation in ascorbate content in fruit crops.
View Article and Find Full Text PDFThe interorganelle communication mediated by membrane contact sites (MCSs) is an evolutionary hallmark of eukaryotic cells. MCS connections enable the nonvesicular exchange of information between organelles and allow them to coordinate responses to changing cellular environments. In plants, the importance of MCS components in the responses to environmental stress has been widely established, but the molecular mechanisms regulating interorganelle connectivity during stress still remain opaque.
View Article and Find Full Text PDFTraumatic injuries are commonly reported in paleopathology. However, fractures of the odontoid process in past populations are uncommon and therefore such injuries may be easily overlooked. This paper describes alterations of the first and second cervical vertebrae, the atlas and axis, of a male individual of advanced age from the medieval necropolis of Maro (Málaga, Spain).
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