Project description:The pathological interaction between oak trees and Phytophthora cinnamomi has implications in the cork oak decline observed over the last decades in the Iberian Peninsula. During host colonization, the phytopathogen secretes effector molecules like elicitins to increase disease effectiveness. The objective of this study was to unravel the proteome changes associated to with the cork oak immune response triggered by P. cinnamomi inoculation in a long-term assay, through SWATH-MS quantitative proteomics performed in the oak leaves. Using the Arabidopis thaliana proteome database as a reference, 424 proteins have been confidently quantified in cork oak leaves, of which 80 proteins showed a p-value below 0.05 or a fold-change greater than 2 or less than 0.5 in their levels between control and inoculated samples being considered as altered. The inoculation of cork oak roots with P. cinnamomi increased the levels of proteins associated with protein-DNA complex assembly, lipid oxidation, response to endoplasmic reticulum stress, and pyridine-containing compound metabolic process in the leaves. In opposition, several proteins associated with cellular metabolic compound salvage and monosaccharide catabolic process had significantly decreased abundances. The most significant abundance variations were observed for the Ribulose 1,5-Bisphosphate Carboxylase small subunit (RBCS1A), Heat Shock protein 90-1 (Hsp90-1), Lipoxygenase 2 (LOX2) and Histone superfamily protein H3.3 (A8MRLO/At4G40030) revealing a pertinent role for these proteins in the host-pathogen interaction mechanism. This work represents the first SWATH-MS analysis performed in cork oak plants inoculated with P. cinnamomi and highlights host proteins that have a relevant action in the homeostatic states that emerge from the interaction between the oomycete and the host in the long term and in a distal organ.
Project description:This work aimed to characterize the molecular adaptations occurring in cork oak (Quercus suber) stems in adaptation to drought, and identify key genetic pathways regulating phellem development. One-year-old cork oak plants were grown for additional 6 months under well-watered (WW) or water-deficit (WD) conditions and main stems were targeted for transcriptomic analysis. WD had a negative impact on secondary growth, decreasing the activity of the vascular cambium and phellogen. Following a tissue-specific approach, we analyzed the transcriptional changes imposed by WD in phellem (outer bark), inner bark, and xylem, and found a global downregulation of genes related to cell division, cell wall biogenesis, lignin and/or suberin biosynthesis. Phellem and phloem showed a concerted upregulation of photosynthesis-related genes, suggesting a determinant role of stem photosynthesis in the adaptation of young plants to long-term drought. The data gathered will be important to further harness the diverse genetic background of this species for the development of optimized management practices.
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.
Project description:We used wheat as rotational crop to assess the influence of continuous cropping on microbiome in Pinellia ternata rhizosphere and the remediation of rotational cropping to the impacted microbiota. Illumina high-throughput sequencing technology was utilized for this method to explore the rhizosphere microbial structure and diversity based on continuous and rotational cropping.
Project description:Arsenic (As) bioavailability in the rice rhizosphere is influenced by many microbial interactions, particularly by metal-transforming functional groups at the root-soil interface. This study was conducted to examine As-transforming microbes and As-speciation in the rice rhizosphere compartments, in response to two different water management practices (continuous and intermittently flooded), established on fields with high to low soil-As concentration. Microbial functional gene composition in the rhizosphere and root-plaque compartments were characterized using the GeoChip 4.0 microarray. Arsenic speciation and concentrations were analyzed in the rhizosphere soil, root-plaque, porewater and grain samples. Results indicated that intermittent flooding significantly altered As-speciation in the rhizosphere, and reduced methyl-As and AsIII concentrations in the pore water, root-plaque and rice grain. Ordination and taxonomic analysis of detected gene-probes indicated that root-plaque and rhizosphere assembled significantly different metal-transforming functional groups. Taxonomic non-redundancy was evident, suggesting that As-reduction, -oxidation and -methylation processes were performed by different microbial groups. As-transformation was coupled to different biogeochemical cycling processes establishing functional non-redundancy of rice-rhizosphere microbiome in response to both rhizosphere compartmentalization and experimental treatments. This study confirmed diverse As-biotransformation at root-soil interface and provided novel insights on their responses to water management, which can be applied for mitigating As-bioavailability and accumulation in rice grains.
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.