Project description:The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. Despite the research on the topic has unravelled the role of several enzymes and transcription factors, many questions remain open, especially those regarding cell development. Here we use the outer bark of cork oak (cork), holm oak (rhytidome), and their natural hybrids’ to further understand the mechanisms underlying periderm development. Cork is an outstanding model as it consists of a thick and very homogeneous periderm produced by a permanent mother-cell layer (phellogen). Conversely, holm oak contains a more heterogeneous bark including several thin periderms mixed with phloem, also known as a rhytidome. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach cork development, allowing an accurate identification of candidate genes and processes. The present study underscores that biotic stress and cell death signalling are enhanced in rhytidome-type barks while lipid metabolism and cell cycle are enriched in cork-type barks. Based on the DEGs most expressed related to development, we highlight that cell division, cell expansion, and cell differentiation could account for the differences found between cork and rhytidome-type barks.
Project description:The periderm of trees produces cork cells, whose cell walls are modified with suberin. We compared the transcriptome of outer bark (cork) vs inner bark (control containing secondary phloem and vacular meristem) to infer genes related to suberim metabolism.
Project description:The phellogen or cork cambium is a bifacial stem cell population from which derivatives are formed by periclinal divisions and specified on opposing sides as phelloderm (inwardly) and phellem or cork (outwardly). Altogether the three layers constitute the periderm which covers and protects the radially-grown organs (stems, roots and tubers) and wounded tissues from dehydration and pathogen attack. The phellem is the final responsible of the protective function of periderm and despite its vital importance, just the suberin biosynthetic process has been studied molecularly while other processes are poorly understood. To shed some light on the phellem cell development from its formation to its final maturation, we used the innercork living material of cork planks extracted from cork oak (Quercus suber) in which we analysed the transcriptome at three time-points: at the beginning (April), maximum (June) and final (July) cork seasonal growth. Since cork presents seasonal growth and the process from phellogen derivative proliferation and specification to phellem cells is continuous, the time-course cork samples were used to approach the phellem cell formation and development. The June enrichment of phellem cells undergoing suberization was confirmed transcriptionally, observing highest expression of suberin-related genes in this month, thus validating our strategy. To highlight the major molecular processes embracing from phellogen to mature phellem cell, the differentially expressed genes between time-points were clustered based on their expression pattern. April transcriptome upregulates the processes involved in the meristem proliferation and maintenance and the triggering of cell differentiation, in agreement with the enrichment of phellogenic cells from which phellem cells are specified. The processes upregulated in Juny and July cork samples, were secondary metabolic processes compatible with the biosynthesis of secondary metabolites deposited within phellem cell wall such as suberin, lignin, extractives including fatty aciyl-derived compounds and triterpenes and also soluble aromatic compounds. The processes with a maximum in July showed upregulation of polyssacharides- and lignin-related processes compatible with a reinforcement of the cork cell wall, presumably related with the latecork formation with smaller and thickened-cells at the end of the growing season. For the above mentioned processes, we discuss the putative function of the most relevant genes in the context of phellem ontogeny. This work provides the most important molecular mechanisms during phellem cell development and provide relevant data for the understanding of the seasonal growth of cork, a material of important circular economic value.
2021-06-16 | GSE155544 | GEO
Project description:Nutrition during early development and pregnancy (NuPED) cohort
| PRJNA735622 | ENA
Project description:Nutrition during early development and pregnancy (NuPED) cohort
Project description:Cork quality is a technological trait of large interest for the Mediterranean cork industry. Our manuscript analyses the proteins and phenolics of cork producing cells in order to collect data about the molecular/biochemical pathways determining cork quality. To the best of our knowledge, this information is sparse in the research and technological community but it would be a valuable tool for breeding. We show that cells leading to the production stoppable (highly valued) and non-stoppable cork have contrasting profiles regarding soluble and cell-wall bound phenolics. The difference was also observed when considering the protein profiles but the discrimination between cork quality groups is not as remarkable as when considering phenolics. In any case, the mitochondrial metabolism points out for higher energy demand in non-stoppable cork producing cells.
Project description:Polymyxins have been a mainstay for the treatment of extensively drug resistant (XDR) Gram-negative bacteria for the past two decades. Many questions regarding the clinical use of polymyxins have been answered, but whether the administration of polymyxins in combination with other antibiotics leads to better outcomes remains unknown. This review discusses the limitations of observational studies that suggest a benefit of combinations of colistin and carbapenems to treat infections caused by carbapenem-resistant Enterobacteriaceae (CRE), especially Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae, and summarizes the results of randomized controlled trials in which treatment with colistin in combination with meropenem or rifampin does not lead to better clinical outcomes than colisitn monotherapy in infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB). Although the introduction of new antibiotics makes it possible to treat certain strains of CRE and carbapenem-resistant P. aeruginosa (CRPA) with polymyxin-sparing regimens, the use of polymyxins is, for now, still necessary in CRAB and in CRE and CRPA harboring metallo-beta-lactamases. Therefore, strategies must be developed to optimize polymyxin-based treatments, informed by in vitro hollow fiber models, careful clinical observations, and high-quality evidence from appropriately designed trials.