DSpace Angular :: Browsing by Author "Meneses, Claudio"

Browsing by Author "Meneses, Claudio"

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A First Omics Data Integration Approach in Hass Avocados to Evaluate Rootstock-Scion Interactions: From Aerial and Root Plant Growth to Fruit Development
(2024) Nunez-Lillo, Gerardo; Ponce, Excequel; Beyer, Clemens P.; Alvaro, Juan E.; Meneses, Claudio; Pedreschi, Romina
Grafting, the careful selection of rootstocks and scions, has played a crucial role maintaining Chilean avocado fruit quality standards in a scenario in which climate change and drought-related issues have considerably decreased avocado fruit production in the last fifteen years. The historical use of seedling rootstocks in Chile has experienced a recent shift towards clonal rootstocks, driven by the potential to produce more consistent and predictable crops. This research aims to compare Hass avocado plants grafted on Mexicola seedling and Dusa (R) clonal rootstocks in a soilless and protected system using (i) a differential expression analysis of root and leaf samples and (ii) a fruit transcriptomic and metabolomic integration analysis to improve our understanding of rootstock-scion interaction and its impact on avocado tree performance and fruit quality. The results demonstrated that no significant transcriptomic and metabolomic differences were identified at fruit level in the ready-to-eat (RTE) stage for Hass avocado fruit from both rootstocks. However, Hass avocados grafted on the clonal rootstock showed greater aerial growth and slightly increased fruit size than the seedling rootstock due to the enrichment of cell wall-remodeling genes as revealed in leaves and fruit at harvest stage.
A multiomics integrative analysis of color de-synchronization with softening of 'Hass' avocado fruit: A first insight into a complex physiological disorder
(2023) Nunez-Lillo, Gerardo; Ponce, Excequel; Arancibia-Guerra, Camila; Carpentier, Sebastien; Carrasco-Pancorbo, Alegria; Olmo-Garcia, Lucia; Chirinos, Rosana; Campos, David; Campos-Vargas, Reinaldo; Meneses, Claudio; Pedreschi, Romina
Exocarp color de-synchronization with softening of 'Hass' avocado is a relevant recurrent problem for the avocado supply chain. This study aimed to unravel the mechanisms driving this de-synchronization integrating omics datasets from avocado exocarp of different storage conditions and color phenotypes. In addition, we propose potential biomarkers to predict color synchronized/de-synchronized fruit. Integration of transcriptomics, proteomics and metabolomics and network analysis revealed eight transcription factors associated with differentially regulated genes between regular air (RA) and controlled atmosphere (CA) and twelve transcription factors related to avocado fruit color de-synchronization control in ready-to-eat stage. CA was positively correlated to auxins, ethylene, cytokinins and brassinosteroids-related genes, while RA was characterized by enrichment of cell wall remodeling and abscisic acid content associated genes. At ready-to-eat higher contents of flavonoids, abscisic acid and brassinosteroids were associated with color-softening synchronized avocados. In contrast, de-synchronized fruit revealed increases of jasmonic acid, salicylic acid and auxin levels.
A novel pectin methylesterase inhibitor, PMEI3, in common bean suggests a key role of pectin methylesterification in Pseudomonas resistance
(2024) De la Rubia, Alfonso G.; Largo-Gosens, Asier; Yusta, Ricardo; Sepulveda-Orellana, Pablo; Riveros, Anibal; Centeno, Maria Luz; Sanhueza, Dayan; Meneses, Claudio; Saez-Aguayo, Susana; Garcia-Angulo, Penelope
The mechanisms underlying susceptibility to and defense against Pseudomonas syringae (Pph) of the common bean (Phaseolus vulgaris) have not yet been clarified. To investigate these, 15-day-old plants of the variety Rinon were infected with Pph and the transcriptomic changes at 2 h and 9 h post-infection were analysed. RNA-seq analysis showed an up-regulation of genes involved in defense/signaling at 2 h, most of them being down-regulated at 9 h, suggesting that Pph inhibits the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall-related genes. Cell wall composition changes at early stages of Pph infection were associated with homogalacturonan methylation and the formation of egg boxes. Among the cell wall genes modulated, a pectin methylesterase inhibitor 3 (PvPMEI3) gene, closely related to AtPMEI3, was detected. PvPMEI3 protein was located in the apoplast and its pectin methylesterase inhibitory activity was demonstrated. PvPMEI3 seems to be a good candidate to play a key role in Pph infection, which was supported by analysis of an Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Arabidopsis Col-0 plants. These results indicate a key role of the degree of pectin methylesterification in host resistance to Pph during the first steps of the attack.
Cell wall disassembly, metabolome and transcriptome analysis in sweet cherry fruit with induced surface pitting
(2023) Ponce, Excequel; Nunez-Lillo, Gerardo; Bravo, Camila; Vidal, Juan; Tapia Reyes, Patricio; Meneses, Claudio; Pedreschi, Romina; Fuentealba, Claudia
Surface pitting is the main quality problem that develops during prolonged storage of sweet cherries. It appears as one or more depressions on the surface of the fruit and is associated with the collapse of cells under the skin of the fruit. However, this physiological disorder is not shown in all cultivars with the same intensity. This research aims to analyze the cell wall disassembly of two cultivars displaying contrasting susceptibility to damage after pitting induction. In addition, we evaluated the metabolomic and transcriptomic changes in sweet cherries during cold storage. Our results show that damage to 'Sweetheart' fruit was more severe than damage to 'Bing' fruit. No differences were observed in the cell wall composition between nonpitted and pitted cherries; however, the varietal differences during cold storage were the most significant. The resistant cultivar 'Bing' showed a longer sidechain of RG-I; instead, 'Sweetheart' PME and PG activity was more marked at the beginning of cold storage. The metabolomics analysis revealed several compounds related to the abiotic stress response, such as 3O-coumaroyl-D-quinic acid, chlorogenic acid, GABA and beta-sitosterol. Furthermore, transcriptomics showed a higher expression of stress-related hormones in the susceptible cultivar and cell wall remodeling-related genes in the resistant cultivar. In conclusion, the contrasting susceptivity to surface pitting in sweet cherries can be attributed to the varietal response to cold storage rather than the mechanical stress of pitting induction.
Color desynchronization with softening of 'Hass' avocado: Targeted pigment, hormone and gene expression analysis
(2022) Arancibia-Guerra, Camila; Nunez-Lillo, Gerardo; Caceres-Mella, Alejandro; Carrera, Esther; Meneses, Claudio; Kuhn, Nathalie; Pedreschi, Romina
Main determinants of 'Hass' avocado quality and consumer acceptance are mesocarp firmness and skin color. Relevant producing and exporting countries have evidenced during the last seasons color desynchronization with softening at edible ripeness. The mechanisms driving this desynchronization are still unknown. Thus, this study aimed to provide a first deep insight into this problem by combining targeted pigment, hormone and gene expression analysis in avocado exocarp samples from different harvests and storage conditions. Results showed that color desynchronization was more pronounced in regular air (RA) condition and early harvest for all or-chards. Prolonged controlled atmosphere (CA) storage synchronized color development in all orchards analyzed. Chlorophylls and carotenoids did not decrease in content as the fruit reached the ready to eat stage but remained stable while total anthocyanins increased in all evaluated orchards. Total anthocyanins and abscisic acid were strongly and positively correlated with the "black color" phenotype. The other evaluated hormones (JA, IAA, SA, tZ, DHZ, iP) revealed negative correlations with the "black color" phenotype. Gene expression related to the ethylene biosynthesis pathway (PamACS, PamETR avocado gene orthologues) showed an up-regulation in fruit phenotyped as ready to eat (RTE) Green. In addition, the expression of the genes orthologues PamPAL, PamF3H and PamCHS was also positively correlated with anthocyanin content in the skin. Our results revealed that color desynchronization with softening of 'Hass' avocado is quite complex in terms of hormonal interplay and the role of storage conditions (RA vs CA). Thus, further studies need broader approaches such as the incorporation of omics studies to elucidate the physiological and molecular mechanisms driving color desynchronization.
Deciphering the behind blackspot exocarp disorder in avocado cv. Hass through a hormonal, transcriptional and metabolic integration approach
(2024) Nunez-Lillo, Gerardo; Hernandez, Ignacia; Olmedo, Patricio; Ponce, Excequel; Arancibia-Guerra, Camila; Sepulveda, Laura; Carrasco-Pancorbo, Alegria; Beiro-Valenzuela, Maria Gemma; Carrera, Esther; Banos, Jorge; Campos, David; Meneses, Claudio; Pedreschi, Romina
Avocado cv. Hass is an important sub-tropical crop with an increasing global demand. However, the avocado supply chain experiences significant fruit losses, particularly during the postharvest stage due to diseases and disorders that manifest after prolonged cold storage or the ready-to-eat stage. The blackspot exocarp disorder, which appears as brown or black blotches only after extended cold storage conditions, leads to substantial commercial losses for exported avocados. This research aimed to identify transcriptomic, metabolomic, and hormonal changes in avocado fruits affected by blackspot disorder, differentiating between the green and black exocarp tissues directly impacted by this physiological disorder. The results showed a correlation between the black-colored exocarp of blackspot affected fruits with high levels of gibberellins, cytokinins, jasmonic acid and salicylic acid hormones. Metabolically, these changes were accompanied by a high fatty acid content of oleate, palmitate and linoleate. Using a metabolic pathway reconstruction analysis, we integrated hormonal and metabolic data with transcriptomic information. This approach identified several genes involved in central carbon metabolism, long-chain fatty acid elongation, and jasmonate/salicylate biosynthesis pathways, as well as a possible accumulation of lignins due to a high expression of genes associated with the phenylpropanoid pathway in the black exocarp of blackspot-affected fruits. These findings suggest that blackspot disorder results from a combination of plant defense mechanisms triggered to strengthen the fruit exocarp tissue.
Global Methylation Analysis Using MSAP Reveals Differences in Chilling-Associated DNA Methylation Changes during Dormancy Release in Contrasting Sweet Cherry Varieties
(2022) Narvaez, Gabriela; Munoz-Espinoza, Claudia; Soto, Esteban; Rothkegel, Karin; Bastias, Macarena; Gutierrez, Jose; Bravo, Soraya; Hasbun, Rodrigo; Meneses, Claudio; Miyasaka Almeida, Andrea
Dormancy is an adaptive strategy developed by temperate perennial crops to protect overwinter tissues from unfavorable environmental conditions. Sweet cherry (Prunus avium L.), a member of the Rosaceae family, requires chilling to overcome dormancy. The time of harvest is directly correlated with chilling requirements in sweet cherries. Consequently, early and late season varieties have low and high chilling requirements, respectively. There is evidence that the expression of dormancy-related genes is regulated by DNA methylation. In this work, methylation-sensitive amplified polymorphism (MSAP) was applied to study genome-wide DNA methylation changes associated with dormancy in two low-chill varieties, 'Royal Dawn' and 'Glen Red', and one high-chill variety, 'Kordia'. Our primary results suggest that the occurrence of progressive DNA demethylation is associated with chilling accumulation during dormancy in the three varieties, independent of their chilling requirements. Genes were identified with different methylation status changes, detected by MSAP, related to cell wall remodeling and energy metabolism. Several MSAP profiles among the varieties were observed, suggesting that fine epigenetic control is required to coordinate hormonal and environmental signals that induce dormancy and its release.
Drosophila DAxud1 Has a Repressive Transcription Activity on Hsp70 and Other Heat Shock Genes
(2023) Zuniga-Hernandez, Jorge; Meneses, Claudio; Bastias, Macarena; Allende, Miguel L.; Glavic, Alvaro
Drosophila melanogaster DAxud1 is a transcription factor that belongs to the Cysteine Serine Rich Nuclear Protein (CSRNP) family, conserved in metazoans, with a transcriptional transactivation activity. According to previous studies, this protein promotes apoptosis and Wnt signaling-mediated neural crest differentiation in vertebrates. However, no analysis has been conducted to determine what other genes it might control, especially in connection with cell survival and apoptosis. To partly answer this question, this work analyzes the role of Drosophila DAxud1 using Targeted-DamID-seq (TaDa-seq), which allows whole genome screening to determine in which regions it is most frequently found. This analysis confirmed the presence of DAxud1 in groups of pro-apoptotic and Wnt pathway genes, as previously described; furthermore, stress resistance genes that coding heat shock protein (HSP) family genes were found as hsp70, hsp67, and hsp26. The enrichment of DAxud1 also identified a DNA-binding motif (AYATACATAYATA) that is frequently found in the promoters of these genes. Surprisingly, the following analyses demonstrated that DAxud1 exerts a repressive role on these genes, which are necessary for cell survival. This is coupled with the pro-apoptotic and cell cycle arrest roles of DAxud1, in which repression of hsp70 complements the maintenance of tissue homeostasis through cell survival modulation.
Identification of grapevine clones via high-throughput amplicon sequencing: a proof-of-concept study
(2023) Urra, Claudio; Sanhueza, Dayan; Pavez, Catalina; Tapia, Patricio; Nunez-Lillo, Gerardo; Minio, Andrea; Miossec, Matthieu; Blanco-Herrera, Francisca; Gainza, Felipe; Castro, Alvaro; Cantu, Dario; Meneses, Claudio
Wine cultivars are available to growers in multiple clonal selections with agronomic and enological differences. Phenotypic differences between clones originated from somatic mutations that accrued over thousands of asexual propagation cycles. Genetic diversity between grape cultivars remains unexplored, and tools to discriminate unequivocally clones have been lacking. This study aimed to uncover genetic variations among a group of clonal selections of 4 important Vitis vinifera cultivars: Cabernet sauvignon, Sauvignon blanc, Chardonnay, and Merlot, and use this information to develop genetic markers to discriminate the clones of these cultivars. We sequenced with short-read sequencing technology the genomes of 18 clones, including biological replicates for a total of 46 genomes. Sequences were aligned to their respective cultivar's reference genome for variant calling. We used reference genomes of Cabernet sauvignon, Chardonnay, and Merlot and developed a de novo genome assembly of Sauvignon blanc using long-read sequencing. On average, 4 million variants were detected for each clone, with 74.2% being single nucleotide variants and 25.8% being small insertions or deletions (InDel). The frequency of these variants was consistent across all clones. From these variants, we validated 46 clonal markers using high-throughput amplicon sequencing for 77.7% of the evaluated clones, most of them small InDel. These results represent an advance in grapevine genotyping strategies and will benefit the viticulture industry for the characterization and identification of the plant material.
Identification of master regulator genes controlling pathogenic CD4⁺ T cell fate in inflammatory bowel disease through transcriptional network analysis
(2024) Jimenez, Jose M.; Contreras-Riquelme, J. Sebastian; Vidal, Pia M.; Prado, Carolina; Bastias, Macarena; Meneses, Claudio; Martin, Alberto J. M.; Perez-Acle, Tomas; Pacheco, Rodrigo
Inflammatory bowel diseases (IBD) are a group of chronic inflammatory conditions of the gastrointestinal tract associated with multiple pathogenic factors, including dysregulation of the immune response. Effector CD4(+) T cells and regulatory CD4(+) T cells (Treg) are central players in maintaining the balance between tolerance and inflammation. Interestingly, genetic modifications in these cells have been implicated in regulating the commitment of specific phenotypes and immune functions. However, the transcriptional program controlling the pathogenic behavior of T helper cells in IBD progression is still unknown. In this study, we aimed to find master transcription regulators controlling the pathogenic behavior of effector CD4(+) T cells upon gut inflammation. To achieve this goal, we used an animal model of IBD induced by the transfer of na & iuml;ve CD4(+) T cells into recombination-activating gene 1 (Rag1) deficient mice, which are devoid of lymphocytes. As a control, a group of Rag1 -/- mice received the transfer of the whole CD4(+) T cells population, which includes both effector T cells and Treg. When gut inflammation progressed, we isolated CD4(+) T cells from the colonic lamina propria and spleen tissue, and performed bulk RNA-seq. We identified differentially up- and down-regulated genes by comparing samples from both experimental groups. We found 532 differentially expressed genes (DEGs) in the colon and 30 DEGs in the spleen, mostly related to Th1 response, leukocyte migration, and response to cytokines in lamina propria T-cells. We integrated these data into Gene Regulatory Networks to identify Master Regulators, identifying four up-regulated master gene regulators (Lef1, Dnmt1, Mybl2, and Jup) and only one down-regulated master regulator (Foxo3). The altered expression of master regulators observed in the transcriptomic analysis was confirmed by qRT-PCR analysis and found an up-regulation of Lef1 and Mybl2, but without differences on Dnmt1, Jup, and Foxo3. These two master regulators have been involved in T cells function and cell cycle progression, respectively. We identified two master regulator genes associated with the pathogenic behavior of effector CD4(+) T cells in an animal model of IBD. These findings provide two new potential molecular targets for treating IBD.
Metabolite Profiling Reveals the Effect of Cold Storage on Primary Metabolism in Nectarine Varieties with Contrasting Mealiness
(2023) Olmedo, Patricio; Zepeda, Baltasar; Delgado-Rioseco, Joaquin; Leiva, Carol; Moreno, Adrian A.; Sagredo, Karen; Blanco-Herrera, Francisca; Pedreschi, Romina; Infante, Rodrigo; Meneses, Claudio; Campos-Vargas, Reinaldo
Chilling injury is a physiological disorder caused by cold storage in peaches and nectarines. The main symptom of chilling injury is mealiness/wooliness, described as a lack of juice in fruit flesh. In this work, we studied two nectarine varieties (Andes Nec-2 and Andes Nec-3) with contrasting susceptibility to mealiness after cold storage. A non-targeted metabolomic analysis was conducted by GC-MS to understand if changes in metabolite abundance are associated with nectarine mealiness induced by cold storage. Multivariate analyses indicated that in unripe nectarines, cold storage promoted a higher accumulation of amino acids in both varieties. Interestingly, for ripe nectarines, cold storage induced an accumulation of fewer amino acids in both varieties and showed an increased abundance of sugars and organic acids. A pathway reconstruction of primary metabolism revealed that in ripe nectarines, cold storage disrupted metabolite abundance in sugar metabolism and the TCA cycle, leading to a differential accumulation of amino acids, organic acids, and sugars in mealy and juicy nectarines.
Metabolomic and biochemical analysis of mesocarp tissues from table grape berries with contrasting firmness reveals cell wall modifications associated to harvest and cold storage
(2022) Balic, Ivan; Olmedo, Patricio; Zepeda, Baltasar; Rojas, Barbara; Ejsmentewicz, Troy; Barros, Miriam; Aguayo, Daniel; Moreno, Adrian A.; Pedreschi, Romina; Meneses, Claudio; Campos-Vargas, Reinaldo
Tissue texture influences the grape berry consumers acceptance. We studied the biological differences between the inner and outer mesocarp tissues in hard and soft berries of table grapes cv NN107. Texture analysis revealed lower levels of firmness in the inner mesocarp as compared with the outer tissue. HPAEC-PAD analysis showed an increased abundance of cell wall monosaccharides in the inner mesocarp of harder berries at harvest. Immunohistochemical analysis displayed differences in homogalacturonan methylesterification and cell wall calcium between soft and hard berries. This last finding correlated with a differential abundance of calcium measured in the alcohol-insoluble residues (AIR) of the inner tissue of the hard berries. Analysis of abundance of polar metabolites suggested changes in cell wall carbon supply precursors, providing new clues in the identification of the biochemical factors that define the texture of the mesocarp of grape berries.
Molecular and Genomic Characterization of the Pseudomonas syringae Phylogroup 4: An Emerging Pathogen of Arabidopsis thaliana and Nicotiana benthamiana
(2022) Zavala, Diego; Fuenzalida, Isabel; Gangas, Maria Victoria; Margutti, Micaela Peppino; Bartoli, Claudia; Roux, Fabrice; Meneses, Claudio; Herrera-Vasquez, Ariel; Blanco-Herrera, Francisca
Environmental fluctuations such as increased temperature, water availability, and air CO2 concentration triggered by climate change influence plant disease dynamics by affecting hosts, pathogens, and their interactions. Here, we describe a newly discovered Pseudomonas syringae strain found in a natural population of Arabidopsis thaliana collected from the southwest of France. This strain, called Psy RAYR-BL, is highly virulent on natural Arabidopsis accessions, Arabidopsis model accession Columbia 0, and tobacco plants. Despite the severe disease phenotype caused by the Psy RAYR-BL strain, we identified a reduced repertoire of putative Type III virulence effectors by genomic sequencing compared to P. syringae pv tomato (Pst) DC3000. Furthermore, hopBJ1(Psy) is found exclusively on the Psy RAYR-BL genome but not in the Pst DC3000 genome. The plant expression of HopBJ1(Psy) induces ROS accumulation and cell death. In addition, HopBJ1(Psy) participates as a virulence factor in this plant-pathogen interaction, likely explaining the severity of the disease symptoms. This research describes the characterization of a newly discovered plant pathogen strain and possible virulence mechanisms underlying the infection process shaped by natural and changing environmental conditions.
Multi-station automatic classification of seismic signatures from the Lascar volcano database
(2023) Salazar, Pablo; Yupanqui, Franz; Meneses, Claudio; Layana, Susana; Yanez, Gonzalo
This study was aimed to build a multi-station automatic classification system for volcanic seismic signatures such as hybrid, long period, tremor, tectonic, and volcano-tectonic events. This system was based on a probabilistic model made using transfer learning, which has, as the main tool, a pre-trained convolutional network named AlexNet. We designed five experiments using different datasets with data that were real, synthetic, two different combinations of these (combined 1 and combined 2), and a balanced subset without synthetic data. The experiment presented the highest scores when a process of data augmentation was introduced into processing sequence. Thus, the lack of real data in some classes (imbalance) dramatically affected the quality of the results, because the learning step (training) was overfitted to the more numerous classes. To test the model stability with variable inputs, we implemented a k-fold cross-validation procedure. Under this approach, the results reached high predictive performance, considering that only the percentage of recognition of the tectonic events (TC) class was partially affected. The results obtained showed the performance of the probabilistic model, reaching high scores over different test datasets. The most valuable benefit of using this technique was that the use of volcano seismic signals from multiple stations provided a more generalizable model which, in the near future, can be extended to multi-volcano database systems. The impact of this work is significant in the evaluation of hazard and risk by monitoring the dynamic evolution of volcanic centers, which is crucial for understanding the stages in a volcano's eruptive cycle.
NAC072 Interacts with HB12, HAT9, and MYBR1 in a Temporal Regulatory Network Controlling Peach Fruit Development
(2023) Nunez-Lillo, Gerardo; Zabala, Jose; Lillo-Carmona, Victoria; Alvarez, Jose Miguel; Pedreschi, Romina; Meneses, Claudio
Fruit development is a complex process that involves the interplay of different biological processes carefully coordinated to control fruit quality traits. The peach fruit development consists in four recognized growth stages (S1-S4). The second stage (S2) is characterized by the endocarp hardening process and is followed by the second exponential growth phase (S3), where an increase in fruit size is produced by a rapid cell expansion. A nectarine genotype incapable of ripening and described as a slow ripening phenotype was identified and selected as a good model for studying peach fruit development. Slow ripening fruit remained firm, green, and exhibited no rise in CO2 or ethylene production rates blocking fruit development at S3 stage. The transcription factor NAC072 has been proposed as a key regulatory element involved in both the slow ripening and the harvest date phenotypes. However, the regulatory mechanisms by which NAC072 produces these phenotypic changes are still unknown. Using a transcriptomic approach between normal and slow ripening individuals with a transcription factor-gene target interaction database, a NAC072 regulatory network was constructed, identifying putative direct and indirect NAC072 fruit development-related elements. Three transcription factors were identified along with NAC072 in early stages of fruit development, two homeobox-leucine zippers (HB12 and HAT9), and one MYB transcription factor (MYBR1). In addition, we determined that the NAC072 transcriptional regulatory network promotes phenylpropanoids biosynthesis and cell wall remodeling to develop fruit growth, seed development, and softening, probably through hormonal signaling pathways involving abscisic acid and gibberellic acid.
Proteomic and Low-Polar Metabolite Profiling Reveal Unique Dynamics in Fatty Acid Metabolism during Flower and Berry Development of Table Grapes
(2023) Olmedo, Patricio; Vidal, Juan; Ponce, Excequel; Defilippi, Bruno G.; Perez-Donoso, Alonso G.; Meneses, Claudio; Carpentier, Sebastien; Pedreschi, Romina; Campos-Vargas, Reinaldo
Grapevine development and ripening are complex processes that involve several biochemical pathways, including fatty acid and lipid metabolism. Fatty acids are essential components of lipids, which play crucial roles in fruit maturation and flavor development. However, the dynamics of fatty acid metabolism in grape flowers and berries are poorly understood. In this study, we present those dynamics and investigate the mechanisms of fatty acid homeostasis on 'Thompson Seedless' berries using metabolomic and proteomic analyses. Low-polar metabolite profiling indicated a higher abundance of fatty acids at the pre-flowering and pre-veraison stages. Proteomic analyses revealed that grape flowers and berries display unique profiles of proteins involved in fatty acid biosynthesis, triacylglycerol assembly, fatty acid beta-oxidation, and lipid signaling. These findings show, for the first time, that fatty acid metabolism also plays an important role in the development of non-oil-rich tissues, opening new perspectives about lipid function and its relation to berry quality.
Proteomic and metabolomic integration reveals the effects of pre-flowering cytokinin applications on central carbon metabolism in table grape berries
(2023) Olmedo, Patricio; Nunez-Lillo, Gerardo; Vidal, Juan; Leiva, Carol; Rojas, Barbara; Sagredo, Karen; Arriagada, Cesar; Defilippi, Bruno G.; Perez-Donoso, Alonso G.; Meneses, Claudio; Carpentier, Sebastien; Pedreschi, Romina; Campos-Vargas, Reinaldo
Consumers around the world prefer high quality table grapes. To achieve higher quality traits at ripening, grapevine producers apply different plant growth regulators. The synthetic cytokinin forchlorfenuron N- (2-chloro-4-pyridinyl)-N '-phenylurea (CPPU) is widely used, its effect on grape quality is poorly understood. We hypothesized that the use of CPPU in pre-flowering can lead to changes in the metabolism that affects grape quality at harvest. Therefore, we investigated the role of CPPU applications on the quality of grapes by inte-grating proteomics and metabolomics. CPPU-treated grapevines showed a significant increase in berry size and firmness. Proteomic analyses indicated that CPPU-treated berries accumulated enzymes associated with carbo-hydrate metabolism, glycolysis, and tricarboxylic acid (TCA) cycle at harvest. Metabolomic analyses showed shifts in the abundance of compounds associated with carbohydrate metabolism and TCA cycle in CPPU-treated grapes. These findings suggest that CPPU applications modulate central carbon metabolism, improving grape berry quality.
Proteomics analysis reveals new insights into surface pitting of sweet cherry cultivars displaying contrasting susceptibility
(2022) Nunez-Lillo, Gerardo; Ponce, Excequel; Alvaro, Juan E.; Campos, David; Meneses, Claudio; Campos-Vargas, Reinaldo; Carpentier, Sebastien; Fuentealba, Claudia; Pedreschi, Romina
Surface pitting in sweet cherry (Prunus avium L.) is characterised by depressions development on the skin surface. Pitting damage happens during harvest and postharvest handling and develops during cold storage. This study compared two cultivars with contrasting susceptibility to pitting (Kordia: tolerant; Sweetheart: susceptible) using a LC-MS/MS proteomic approach to identify key metabolic and signalling pathways related to this disorder during ripening and postharvest storage. The variability observed in the principal component analysis was driven by the cultivars suggesting that surface pitting susceptibility is triggered by the inherent differences between cultivars. Proteins involved in anthocyanin biosynthesis were more abundant in Kordia. Moreover, CCR (cinnamoyl-CoA reductase) and FLS (flavonol synthase) proteins showed higher abundance in Sweetheart. An overexpression in enzymes related to the synthesis of abscisic acid (ABA), jasmonic acid (JA) and ethylene were found in Kordia. A higher abundance of sucrose synthase (SUS), UDP-glycosyltransferases (UDP-GT) and polygalacturonase-inhibiting proteins (PGIP) were observed in Kordia, while a higher content of invertase (INV) was observed in Sweetheart. The overexpression of the studied pathways suggests that tolerance to surface pitting could be correlated to one or more of these factors, and susceptibility might be given by the inherent differences in the metabolic processes of each cultivar.
Response Mechanisms of "Hass" Avocado to Sequential 1-methylcyclopropene Applications at Different Maturity Stages during Cold Storage
(2022) Olivares, Daniela; Garcia-Rojas, Miguel; Ulloa, Pablo A.; Riveros, Anibal; Pedreschi, Romina; Campos-Vargas, Reinaldo; Meneses, Claudio; Defilippi, Bruno G.
1-Methylcyclopropene (1-MCP) is used for extending the postharvest life of the avocado during storage. Evaluated the effect of 1-MCP application at different times after harvest, i.e., 0, 7, 14, and 21 d at 5 degrees C, to identify the threshold of the ethylene inhibition response in "Hass" avocado. Our results showed that fruits from two maturity stages at harvest: low dry matter (20-23%) and high dry matter (27%). Changes in ethylene production rates and transcript accumulation of genes involved in ethylene metabolism were measured at harvest and during storage. 1-MCP treated fruit up to 14 d of storage showed similar values of firmness and skin color as fruit treated at harvest time. In contrast, when the application was performed after 21 d, the fruit showed ripening attributes similar to those of the untreated ones. To further understand the molecular mechanisms responsible for the lack of response to 1-MCP at 21 d of storage, transcriptomic analysis was performed. Gene ontology analyses based on the DEG analysis showed enrichment of transcripts involved in the 'response to ethylene' for both maturity stages. All genes evaluated showed similar expression profiles induced by cold storage time, with a peak at 21 d of storage and an increased softening of the fruit and peel color. This was a two-year field study, and results were consistent across the two experimental years. Our results should help growers and markets in selecting the optimal timing of 1-MCP application in "Hass" avocados and should contribute to a deeper understanding of the molecular mechanisms of the avocado ripening process.
Structural insights into a functional unit from an immunogenic mollusk hemocyanin
(2024) Munoz, Sebastian M.; Vallejos-Baccelliere, Gabriel; Manubens, Augusto; Salazar, Michelle L.; Nascimento, Andrey F. Z.; Tapia-Reyes, Patricio; Meneses, Claudio; Ambrosio, Andre L. B.; Becker, Maria Ines; Guixe, Victoria; Castro-Fernandez, Victor
Mollusk hemocyanins, among the largest known proteins, are used as immunostimulants in biomedical and clinical applications. The hemocyanin of the Chilean gastropod Concholepas concholepas (CCH) exhibits unique properties, which makes it safe and effective for human immunotherapy, as observed in animal models of bladder cancer and melanoma, and dendritical cell vaccine trials. Despite its potential, the structure and amino acid sequence of CCH remain unknown. This study reports two sequence fragments of CCH, representing three complete functional units (FUs). We also determined the high -resolution (1.5 A & ring; ) X-ray crystal structure of an "FU -g type"from the CCHB subunit. This structure enables in-depth analysis of chemical interactions at the copper -binding center and unveils an unusual, truncated N-glycosylation pattern. These features are linked to eliciting more robust immunological responses in animals, offering insights into CCH's enhanced immunostimulatory properties and opening new avenues for its potential applications in biomedical research and therapies.

Browsing by Author "Meneses, Claudio"

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