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Ítem Acceso Abierto Exploring multitasking proteins in Xanthomonas secretomes: Insights into mechanisms of plant-pathogen interactions(Elsevier, 2025-03-20) De Almeida Barbosa Assis, Renata; Paulino de Oliveira, Amanda Carolina; Souza Carvalho, Flávia Maria; Aparecido Ferro, Jesus; De Souza, Robson Francisco; Orellano, Elena G.; Almeida, Nalvo Franco; García Machado, Camila Carrião; Dandekar, Abhaya M.; Chakraborty, Sandeep; Varani, Alessandro M.; Moreira, Leandro MarcioRecent advances in large-scale functional genomic analysis have significantly increased interest in multitask proteins. The role of these proteins in Xanthomonas phytopathogens, a model for plantpathogen interaction studies, remains largely underexplored. In this study, we introduce an innovative systematic comparative analysis of secretomes from 18 different Xanthomonas species, integrating data from multiple proteomic studies to identify potential multitasking proteins. This approach led to the identification of 93 proteins primarily involved in central metabolism that are secreted under various physiological conditions, including 16 previously characterized moonlighting proteins. Promiscuity analysis of five selected enzymes revealed that three (asparaginase, chorismate mutase, and phosphoenolpyruvate synthase) exhibit high potential for catalyzing reactions with non-canonical substrates, suggesting additional functional roles beyond their primary enzymatic activities. Additionally, we re-annotated previously hypothetical secreted proteins, assigning functions related to central metabolism and indicating a high potential for promiscuous activity. This comprehensive compilation of potential moonlighting and promiscuous proteins in Xanthomonas provides new insights into the molecular mechanisms driving plantpathogen interactions and establishes a foundation for future experimental validations of theseÍtem Acceso Abierto Neuroprotective effect of NSCs-derived extracellular vesicles in Parkinson's disease models(Springer Nature, 2025-02-19) Díaz Reyes, Mercyleidi; Gatti, Sabrina; Delgado Ocaña, Susana; Ortega, Hugo H.; Banchio, Claudia; Dr. Wolozin, Benjamin: provide the WT/A53T α-syn DNA constructParkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by both motor and non-motor symptoms, caused by the degeneration and loss of dopaminergic neurons in the substantia nigra. Current therapies are limited to symptom management, unable to prevent neuronal loss or halt the progression of the disease. A significant limitation to more effective treatments is the difficulty of crossing the blood-brain barrier (BBB). Extracellular vesicles (EVs) communication plays a crucial role in several physiological processes within the nervous system. Notably, EVs have the unique ability to cross the BBB, making them a highly promising vehicle for delivering therapeutic agents directly to the brain. Given the rising prevalence of PD, the need for therapies that prevent neuronal death and promote cell survival is urgent. This study explores the potential of neural stem cell-derived extracellular vesicles (NSC-EVs) using two in vitro models of PD. Our findings demonstrate that NSC-EVs significantly enhance the survival of dopaminergic neurons by reducing apoptosis and showing strong neuroprotective effects. Notably, the natural extracellular vesicles used in this study are enriched with Catalase, a potent scavenger protein with antioxidant properties. This natural enrichment further strengthens their neuroprotective capacity, enabling them to mitigate oxidative stress and protect vulnerable neurons. The use of such naturally enriched extracellular vesicles represents a promising approach for developing innovative therapies to effectively combat Parkinson’s disease.Ítem Acceso Abierto Seedling emergence and herbage yield of summer-active tall fescue sown at different times and sowing depths(Wiley, 2025-03-06) Beribe, María José; Barletta, Pablo; Scheneiter, Jorge Omar; https://orcid.org/0000-0002-3445-1219Background: Tall fescue is sensitive to sowing depth and, in the Pampas region of Argentina, its sowing is often delayed from autumn (average air temperature 18.5°C) to winter (average air temperature 10.0°C). Since tall fescue is sensitive to the sowing depth, and temperature determines the emergence period, this study aimed to evaluate the effect of sowing depth at different times on seedling emergence and herbage yield. Methods: Two field experiments were carried out in Pergamino, Buenos Aires province, Argentina, to evaluate a summer-active tall fescue at two sowing times and five sowing depths. The emergence of seedlings and the herbage yield in the year of sowing were determined. Results: Seedling emergence was maximal when sown at 1.2–1.5 cm depth and at 230 growing degree days (GDD) in early autumn and 257 GDD in winter. In both years and sowing seasons, herbage yield was positively related to the number of seedlings at maximum emergence. Conclusions: No differences in seedling emergence were observed between the autumn and winter sowings, and the emergence of tall fescue was well explained by the thermal time. The concept of “critical depth” was determined as the sowing depth at which the greatest seedling emergence and forage yield are achieved.Ítem Acceso Abierto Editorial: Health-stress-disease triangle. Pathophysiological focus and perspectives(Frontiers Media, 2024-05-17) Capurro, Claudia; Sobrevia, Luis; Larocca, María Cecilia; Cremaschi, Graciela Alicia; Vila Petroff, MartinThis Frontiers Research Topic emerged as an outcome of the 2022 annual joint meeting of the Argentinean Society of Physiology (SAFIS) and the Latin American Association of Physiological Sciences (ALACF). Targeted to highlight physiological and pathophysiological studies focused on the interrelation between health, stress and disease and the molecular pathways that either favour, break or reverse this unidirectional path. The articles published herein reveal groundbreaking research on the response of the cardiovascular system to diverse stress signals.Ítem Acceso Abierto Integrated metabolomic, lipidomic and proteomic analysis define the metabolic changes occurring in curled areas in leaves with leaf peach curl disease(Wiley, 2025-06-02) Novello, María Angelina; Bustamante, Claudia Anabel; Svetaz, Laura Andrea; Goldy, Camila; Valentini, Gabriel Hugo; Drincovich, María Fabiana; Brotman, Yariv; Fernie, Alisdair R.; Lara, María Valeria; https://orcid.org/0000-0003-4914-0242Peach Leaf Curl Disease, caused by Taphrina deformans, is characterized by reddish hypertrophic and hyperplasic leaf areas. To comprehend the biochemical imbalances caused by the fungus, dissected symptomatic (C) and asymptomatic areas (N) from leaves with increasing disease extension were analyzed by an integrated approach including metabolomics, lipidomics, proteomics, and complementary biochemical techniques. Drastic metabolic differences were identified in C areas with respect to either N areas or healthy leaves, including altered chloroplastic functioning and composition, which differs from the typical senescence process. In C areas, alteration in redox-homoeostasis proteins and in triacylglycerols content, peroxidation and double bond index were observed. Proteomic data revealed induction of host enzymes involved in auxin and jasmonate biosynthesis and an upregulation of phenylpropanoid and mevalonate pathways and downregulation of the plastidic methylerythritol phosphate route. Amino acid pools were affected, with upregulation of proteins involved in asparagine synthesis. Curled areas exhibited a metabolic shift towards functioning as a sink tissue importing sugars, probably from N areas, and producing energy through fermentation and respiration and reductive power via the pentose phosphate route. Identifying the metabolic disturbances leading to disease symptoms is a key step in designing strategies to prevent or delay the progression of the disease.Ítem Acceso Abierto Microtubules regulate brush border formation(Wiley, 2017-11-06) Tonucci, Facundo Mauro; Ferretti, Anabela Cecilia; Almada, Evangelina; Cribb, Pamela; Vena, Rodrigo; Hidalgo, Florencia; Favre, Cristian; Tyska, Matt J.; Kaverina, Irina; Larocca, María Cecilia; https://orcid.org/0000-0002-6967-5431Most epithelial cells contain apical membrane structures associated to bundles of actin filaments, which constitute the brush border. Whereas microtubule participation in the maintenance of the brush border identity has been characterized, their contribution to de novo microvilli organization remained elusive. Hereby, using a cell model of individual enterocyte polarization, we found that nocodazole induced microtubule depolymerization prevented the de novo brush border formation. Microtubule participation in brush border actin organization was confirmed in polarized kidney tubule MDCK cells. We also found that centrosome, but not Golgi derived microtubules, were essential for the initial stages of brush border development. During this process, microtubule plus ends acquired an early asymmetric orientation toward the apical membrane, which clearly differs from their predominant basal orientation in mature epithelia. In addition, overexpression of the microtubule plus ends associated protein CLIP170, which regulate actin nucleation in different cell contexts, facilitated brush border formation. In combination, the present results support the participation of centrosomal microtubule plus ends in the activation of the polarized actin organization associated to brush border formation, unveiling a novel mechanism of microtubule regulation of epithelial polarity.Ítem Acceso Abierto Algae(Nature Research, 2025-01-15) Gomez Casati, Diego Fabián; Pernice, Mathieu; Tonon, Thierry; http://orcid.org/0000-0002-4569-2579; http://orcid.org/0000-0002-3431-2104; http://orcid.org/0000-0002-1454-6018Algae are versatile photosynthetic organisms, with remarkable adaptability and metabolic properties that allow them to live in diverse and extreme habitats, as well as holding great potential for biotechnology. They play fundamental roles in their environments, including primary production, carbon fixation, and engineering their ecosystems. Advances in research on these organisms have been lagging behind bacteria, fungi, plants and animals, but the situation is rapidly evolving thanks to the development of new tools and resources. In this context, the current Collection covers diverse topics including the biology, ecology, conservation and biotechnology of algae.Ítem Acceso Abierto Mutations increasing cofactor affinity, improve stability and activity of a Baeyer Villiger monooxygenase(American Chemical Society, 2022-09-13) Mansouri, Hamid R.; Gracia Carmona, Oriol; Jodlbauer, Julia; Schweiger, Lorenz; Fink, Michael J.; Breslmayr, Erik; Laurent, Christophe; Feroz, Saima; Goncalves, Leticia C. P.; Rial, Daniela V.; Mihovilovic, Marko D.; Bommarius, Andreas S.; Ludwig, Roland; Oostenbrink, Chris; Rudroff, Florian; https://orcid.org/0000-0001-6560-9106; https://orcid.org/0000-0002-9944-1396; https://orcid.org/0000-0002-9112-6981; https://orcid.org/0000-0003-4658-1675; https://orcid.org/0000-0002-5058-5874; https://orcid.org/0000-0002-4232-2556; https://orcid.org/0000-0002-6680-8200The typically low thermodynamic and kinetic stability of enzymes is a bottleneck for their application in industrial synthesis. Baeyer−Villiger monooxygenases, which oxidize ketones to lactones using aerial oxygen, among other activities, suffer particularly from these instabilities. Previous efforts in protein engineering have increased thermodynamic stability but at the price of decreased activity. Here, we solved this trade-off by introducing mutations in a cyclohexanone monooxygenase from Acinetobacter sp., guided by a combination of rational and structure-guided consensus approaches. We developed variants with improved activity (1.5- to 2.5-fold) and increased thermodynamic (+5 °C Tm) and kinetic stability (8-fold). Our analysis revealed a crucial position in the cofactor binding domain, responsible for an 11-fold increase in affinity to the flavin cofactor, and explained using MD simulations. This gain in affinity was compatible with other mutations. While our study focused on a particular model enzyme, previous studies indicate that these findings are plausibly applicable to other BVMOs, and possibly to other flavin-dependent monooxygenases. These new design principles can inform the development of industrially robust, flavin-dependent biocatalysts for various oxidations.Ítem Acceso Abierto Structural features of the plant N-recognin ClpS1 and sequence determinants in its targets that govern substrate selection(Federation of European Biochemical Societies, 2021-06-14) Aguilar Lucero, Dianela Ailin; Cantoia, Alejo; Sánchez López, Carolina; Binolfi, Andrés; Mogk, Axel; Ceccarelli, Eduardo Augusto; Rosano, Germán L.; https://orcid.org/0000-0001-5776-3306; https://orcid.org/0000-0002-8313-6813; Dr. Song, Hyun-kyu: provide the coordinates of ClpS1 (PDB 7d34)In the N-degron pathway of protein degradation of Escherichia coli, the N-recognin ClpS identifies substrates bearing N-terminal phenylalanine, tyrosine, tryptophan, or leucine and delivers them to the caseinolytic protease (Clp). Chloroplasts contain the Clp system, but whether chloroplastic ClpS1 adheres to the same constraints is unknown. Moreover, the structural underpinnings of substrate recognition are not completely defined. We show that ClpS1 recognizes canonical residues of the E. coli N-degron pathway. The residue in second position influences recognition (especially in N-terminal ends starting with leucine). N-terminal acetylation abrogates recognition. ClpF, a ClpS1-interacting partner, does not alter its specificity. Substrate binding provokes local remodeling of residues in the substrate-binding cavity of ClpS1. Our work strongly supports the existence of a chloroplastic N-degron pathway.Ítem Acceso Abierto Activation of spleen tyrosine kinase (Syk) at fertilization in Rhinella arenarum eggs(University of the Basque Country Press (UBC Press), 2015-07-02) Mouguelar, Valeria Soraya; Coux, GabrielaRecently, we have provided evidence for the involvement of a cytosolic tyrosine–phosphorylatable 70 kDa oocyte protein in Rhinella arenarum (Anura: Bufonidae) fertilization. The aim of the present work was to characterize its phosphorylation, determine the identity of this protein and establish its biological role during the fertilization process. Tyrosine phosphorylation of the 70 kDa protein was not observed in eggs activated with the calcium ionophore A23187. Pretreatment of oocytes with the tyrosine kinase inhibitor genistein effectively blocked the fertilization-dependent phosphorylation of the 70 kDa protein. In order to identify this protein, we examined the presence in amphibian oocytes of non-receptor 70 kDa tyrosine kinase members of the Syk/Zap70 and Tec families by RT-PCR using degenerate primers. We found that R. arenarum oocytes contain the transcripts coding for Syk and Tec kinases. Western blot analysis confirmed the presence of Syk protein in unfertilized oocytes and eggs. Studies using phospho-Syk specific antibodies showed that fertilization rapidly (less than 10 minutes) induces phosphorylation on Syk tyrosine residues (352 and 525/526) that are necessary for the activation of the enzyme. Finally, specific inhibition of Syk with the R406 compound provoked a diminished fertilization score, thereby confirming a functional role of the Syk protein during R. arenarum fertilization. To our knowledge this is the first time that Syk is described as a player in the signaling cascade activated after fertilization.Ítem Desconocido D- and N-Methyl Amino Acids for Modulating the Therapeutic Properties of Antimicrobial Peptides and Lipopeptides(MDPI, 2023-04-27) Humpola, Maria Veronica; Spinelli, Roque; Erben, Melina; Perdomo, Virginia Gabriela; Tonarelli, Georgina Guadalupe; Albericio, Fernando; Siano, Alvaro Sebastian; https://orcid.org/0000-0003-4479-2356; https://orcid.org/0000-0002-8946-0462; https://orcid.org/0000-0002-7790-5532Here we designed and synthesized analogs of two antimicrobial peptides, namely C10:0-A2, a lipopeptide, and TA4, a cationic α-helical amphipathic peptide, and used non-proteinogenic amino acids to improve their therapeutic properties. The physicochemical properties of these analogs were analyzed, including their retention time, hydrophobicity, and critical micelle concentration, as well as their antimicrobial activity against gram-positive and gram-negative bacteria and yeast. Our results showed that substitution with D- and N-methyl amino acids could be a useful strategy to modulate the therapeutic properties of antimicrobial peptides and lipopeptides, including enhancing stability against enzymatic degradation. The study provides insights into the design and optimization of antimicrobial peptides to achieve improved stability and therapeutic efficacy. TA4(dK), C10:0-A2(6-NMeLys), and C10:0-A2(9-NMeLys) were identified as the most promising molecules for further studies.Ítem Desconocido Expression of Flavodiiron Proteins Flv2-Flv4 in Chloroplasts of Arabidopsis and Tobacco Plants Provides Multiple Stress Tolerance(MDPI, 2021-01-25) Vicino, Paula; Carrillo, Julieta; Gómez, Rodrigo Lionel; Shahinnia, Fahimeh; Tula, Suresh; Melzer, Michael; Rutten, Twan; Carrillo, Néstor; Hajirezaei, Mohammad-Reza; Lodeyro, Anabella F.; https://orcid.org/0000-0002-8789-0899; https://orcid.org/0000-0001-8236-7647; https://orcid.org/0000-0002-5213-4030With the notable exception of angiosperms, all phototrophs contain different sets of flavodiiron proteins that help to relieve the excess of excitation energy on the photosynthetic electron transport chain during adverse environmental conditions, presumably by reducing oxygen directly to water. Among them, the Flv2-Flv4 dimer is only found in β-cyanobacteria and induced by high light, supporting a role in stress protection. The possibility of a similar protective function in plants was assayed by expressing Synechocystis Flv2-Flv4 in chloroplasts of tobacco and Arabidopsis. Flv-expressing plants exhibited increased tolerance toward high irradiation, salinity, oxidants, and drought. Stress tolerance was reflected by better growth, preservation of photosynthetic activity, and membrane integrity. Metabolic profiling under drought showed enhanced accumulation of soluble sugars and amino acids in transgenic Arabidopsis and a remarkable shift of sucrose into starch, in line with metabolic responses of drought-tolerant genotypes. Our results indicate that the Flv2-Flv4 complex retains its stress protection activities when expressed in chloroplasts of angiosperm species by acting as an additional electron sink. The flv2-flv4 genes constitute a novel biotechnological tool to generate plants with increased tolerance to agronomically relevant stress conditions that represent a significant productivity constraint.Ítem Desconocido New tools for recombinant proteinproduction in Escherichia coli:A 5-year update(Wiley, 2019-06-01) Rosano, Germán L.; Morales, Enrique Salvador; Ceccarelli, Eduardo Augusto; https://orcid.org/0000-0002-8313-6813; https://orcid.org/0000-0001-5776-3306The production of proteins in sufficient amounts is key for their study or use asbiotherapeutic agents. Escherichia coli is the host of choice for recombinant protein production givenits fast growth, easy manipulation, and cost-effectiveness. As such, its protein production capabilitiesare continuously being improved. Also, the associated tools (such as plasmids and cultivationconditions) are subject of ongoing research to optimize product yield. In this work, we review thelatest advances in recombinant protein production in E. coli.Ítem Desconocido Cnbp ameliorates Treacher Collins Syndrome craniofacial anomalies through a pathway that involves redox-responsive genes(Springer Nature, 2016-10-06) Porcel de Peralta, Mauro S.; Mouguelar, Valeria Soraya; Sdrigotti, María Antonella; Ishiy, Felipe A. A.; Fanganiello, Roberto D.; Passos Bueno, Maria R.; Coux, Gabriela; Calcaterra, Nora B.Treacher Collins Syndrome (TCS) is a rare congenital disease (1:50 000 live births) characterized by craniofacial defects, including hypoplasia of facial bones, cleft palate and palpebral fissures. Over 90% of the cases are due to mutations in the TCOF1 gene, which codifies the nucleolar protein Treacle. Here we report a novel TCS-like zebrafish model displaying features that fully recapitulate the spectrum of craniofacial abnormalities observed in patients. As it was reported for a Tcof1+/ − mouse model, Treacle depletion in zebrafish caused reduced rRNA transcription, stabilization of Tp53 and increased cell death in the cephalic region. An increase of ROS along with the overexpression of redox-responsive genes was detected; furthermore, treatment with antioxidants ameliorated the phenotypic defects of craniofacial anomalies in TCS-like larvae. On the other hand, Treacle depletion led to a lowering in the abundance of Cnbp, a protein required for proper craniofacial development. Tcof1 knockdown in transgenic zebrafish overexpressing cnbp resulted in barely affected craniofacial cartilage development, reinforcing the notion that Cnbp has a role in the pathogenesis of TCS. The cnbp overexpression rescued the TCS phenotype in a dose-dependent manner by a ROScytoprotective action that prevented the redox-responsive genes’ upregulation but did not normalize the synthesis of rRNAs. Finally, a positive correlation between the expression of CNBP and TCOF1 in mesenchymal cells from both control and TCS subjects was found. Based on this, we suggest CNBP as an additional target for new alternative therapeutic treatments to reduce craniofacial defects not only in TCS but also in other neurocristopathies.Ítem Desconocido Neural stem cell-derived extracellular vesicles favour neuronal differentiation and plasticity under stress conditions(Frontiers Media, 2023-03-24) Delgado Ocaña, Susana; Magaquian, Dario; Banchio, ClaudiaExtracellular vesicles (EVs) are released by all cell types and are involved in intercellular communication. We evaluated if neural stem cells-derived EVs (NSCEVs) regulate NSCs proliferation and differentiation under control and stress conditions. We found that NSC-EVs treatment increases cell proliferation and promotes neuronal differentiation and plasticity. The fact that nervous tissue poorly recovers after cellular damage, prump us to evaluate the effect of EVs supplementation under oxidative stress and inflammation. We demonstrate that NSC-EVs restore the proliferative potential of the NSCs affected by oxidative stress. In addition, we provide evidence that oxidative stress and inflammation induce neuronal differentiation. Interestingly, the aberrant cell phenotype induced by inflammation is restored by NSC-EVs treatment, suggesting that these vesicles ameliorate the damage burden in neurons and modulate neuronal plasticity. These results contribute to understand the role of the NSCs-derived EVs as key players for brain tissue generation and regeneration and open new pathways to the development of therapies.Ítem Desconocido Ready for new waves: optimizing SARS-CoV-2 variants monitoring in pooled samples with droplet digital PCR(Frontiers Media, 2024-01-11) Pacini, Antonella; Paredes, Franco; Heckel, Sofía; Ibarra, Guadalupe; Petreli, María Victoria; Perez, Marilina; Agnella, Yanina; Piskulic, Laura; Allasia, María Belén; Caprile, Luis; Colaneri, Alejandro; Sesma, JulianaIntroduction: The declaration of the end of the Public Health Emergency for COVID-19 on May 11th, 2023, has shifted the global focus led by WHO and CDC towards monitoring the evolution of SARS-CoV-2. Augmenting these international endeavors with local initiatives becomes crucial to not only track the emergence of new variants but also to understand their spread. We present a cost-effective digital PCR-based pooled sample testing methodology tailored for early variant surveillance. Methods: Using 1200 retrospective SARS-CoV-2 positive samples, either negative or positive for Delta or Omicron, we assessed the sensitivity and specificity of our detection strategy employing commercial TaqMan variant probes in a 1:9 ratio of variant-positive to variant-negative samples. Results: The study achieved 100% sensitivity and 99% specificity in 10-sample pools, with an Area Under the Curve (AUC) exceeding 0.998 in ROC curves, using distinct commercial TaqMan variant probes. Discussion: The employment of two separate TaqMan probes for both Delta and Omicron establishes dual validation routes, emphasizing the method’s robustness. Although we used known samples to model realistic emergence scenarios of the Delta and Omicron variants, our main objective is to demonstrate the versatility of this strategy to identify future variant appearances. The utilization of two divergent variants and distinct probes for each confirms the method’s independence from specific variants and probes. This flexibility ensures it can be tailored to recognize any subsequent variant emergence, given the availability of its sequence and a specific probe. Consequently, our approach stands as a robust tool for tracking and managing any new variant outbreak, reinforcing our global readiness against possible future SARS-CoV-2 waves.Ítem Desconocido Reactive oxygen species generated in chloroplasts contribute to tobacco leaf infection by the necrotrophic fungus Botrytis cinerea(Society for Experimental Biology, 2017-10) Rossi, Franco R.; Krapp, Adriana R.; Bisaro, Fabiana; Maiale, Santiago J.; Pieckenstain, Fernando L.; Carrillo, NéstorReactive oxygen species (ROS) play fundamental roles in plant responses to pathogen infection, including modulation of cell death processes and defense-related gene expression. Cell death triggered as part of the hypersensitive response enhances resistance to biotrophic pathogens, but favors the virulence of necrotrophs. Even though the involvement of ROS in the orchestration of defense responses is well established, the relative contribution of specific subcellular ROS sources to plant resistance against microorganisms with different pathogenesis strategies is not completely known. The aim of this work was to investigate the role of chloroplastic ROS in plant defense against a typical necrotrophic fungus, Botrytis cinerea. For this purpose, we used transgenic Nicotiana tabacum (tobacco) lines expressing a plastid-targeted cyanobacterial flavodoxin (pfld lines), which accumulate lower chloroplastic ROS in response to different stresses. Tissue damage and fungal growth were significantly reduced in infected leaves of pfld plants, as compared with infected wild-type (WT) counterparts. ROS build-up triggered by Botrytis infection and associated with chloroplasts was significantly decreased (70–80%) in pfld leaves relative to the wild type. Phytoalexin accumulation and expression of pathogenesis-related genes were induced to a lower degree in pfld plants than in WT siblings. The impact of fungal infection on photosynthetic activity was also lower in pfld leaves. The results indicate that chloroplast-generated ROS play a major role in lesion development during Botrytis infection. This work demonstrates that the modulation of chloroplastic ROS levels by the expression of a heterologous antioxidant protein can provide a significant degree of protection against a canonical necrotrophic fungus.Ítem Desconocido Early cold stress responses in post-meiotic anthers from tolerant and sensitive rice cultivars(SpringerOpen, 2019-12-18) González Schain, Nahuel; Roig-Villanova, Irma; Kater, Martin M.; http://orcid.org/0000-0003-1155-2575Background: Rice grain production is susceptible to a changing environment that imposes both biotic and abiotic stress conditions. Cold episodes are becoming more frequent in the last years and directly affect rice yield in areas with a temperate climate. Rice is particularly susceptible to cold stress during the reproductive phase, especially in anthers during post-meiotic stages which, in turn, affect pollen production. However, a number of rice cultivars with a certain degree of tolerance to cold have been described, which may represent a good breeding resource for improvement of susceptible commercial varieties. Plants experiencing cold stress activate a molecular response in order to reprogram many metabolic pathways to face these hostile conditions. Results: Here we performed RNA-seq analysis using cold-stressed post-meiotic anther samples from a cold-tolerant, Erythroceros Hokkaido (ERY), and a cold-susceptible commercial cultivar Sant’Andrea (S.AND). Both cultivars displayed an early common molecular response to cold, although the changes in expression levels are much more drastic in the tolerant one. Comparing our datasets, obtained after one-night cold stress, with other similar genome-wide studies showed very few common deregulated genes, suggesting that molecular responses in coldstressed anthers strongly depend on conditions and the duration of the cold treatments. Cold-tolerant ERY exhibits specific molecular responses related to ethylene metabolism, which appears to be activated after cold stress. On the other hand, S.AND cold-treated plants showed a general downregulation of photosystem I and II genes, supporting a role of photosynthesis and chloroplasts in cold responses in anthers, which has remained elusive. Conclusions: Our study revealed that a number of ethylene-related transcription factors, as putative master regulators of cold responses, were upregulated in ERY providing promising candidates to confer tolerance to susceptible cultivars. Our results also suggest that the photosynthesis machinery might be a good target to improve cold tolerance in anthers. In summary, our study provides valuable candidates for further analysis and molecular breeding for cold-tolerant rice cultivars.Ítem Desconocido Characterization of the accessory protein ClpT1 from Arabidopsis thaliana: oligomerization status and interaction with Hsp100 chaperones(BMC, 2014-08-24) Colombo, Clara V.; Ceccarelli, Eduardo Augusto; Rosano, Germán L.Background: The caseinolytic protease (Clp) is crucial for chloroplast biogenesis and proteostasis. The Arabidopsis Clp consists of two heptameric rings (P and R rings) assembled from nine distinct subunits. Hsp100 chaperones (ClpC1/2 and ClpD) are believed to dock to the axial pores of Clp and then transfer unfolded polypeptides destined to degradation. The adaptor proteins ClpT1 and 2 attach to the protease, apparently blocking the chaperone binding sites. This competition was suggested to regulate Clp activity. Also, monomerization of ClpT1 from dimers in the stroma triggers P and R rings association. So, oligomerization status of ClpT1 seems to control the assembly of the Clp protease. Results: In this work, ClpT1 was obtained in a recombinant form and purified. In solution, it mostly consists of monomers while dimers represent a small fraction of the population. Enrichment of the dimer fraction could only be achieved by stabilization with a crosslinker reagent. We demonstrate that ClpT1 specifically interacts with the Hsp100 chaperones ClpC2 and ClpD. In addition, ClpT1 stimulates the ATPase activity of ClpD by more than 50% when both are present in a 1:1 molar ratio. Outside this optimal proportion, the stimulatory effect of ClpT1 on the ATPase activity of ClpD declines. Conclusions: The accessory protein ClpT1 behaves as a monomer in solution. It interacts with the chloroplastic Hsp100 chaperones ClpC2 and ClpD and tightly modulates the ATPase activity of the latter. Our results provide new experimental evidence that may contribute to revise and expand the existing models that were proposed to explain the roles of this poorly understood regulatory protein.Ítem Acceso Abierto Deciphering the metabolic pathways influencing heat and cold responses during post-harvest physiology of peach fruit(Wiley, 2014-01-21) Lauxmann, Martín Alexander; Borsani, Julia; Osorio, Sonia; Lombardo, Verónica Andrea; Budde, Claudio O.; Bustamante, Claudia Anabel; Monti, Laura Lucía; Andreo, Carlos Santiago; Fernie, Alisdair R.; Drincovich, María Fabiana; Lara, María ValeriaPeaches are highly perishable and deteriorate quickly at ambient temperature. Cold storage is commonly used to prevent fruit decay; however, it affects fruit quality causing physiological disorders collectively termed ‘chilling injury’ (CI). To prevent or ameliorate CI, heat treatment is often applied prior to cold storage. In the present work, metabolic profiling was performed to determine the metabolic dynamics associated with the induction of acquired CI tolerance in response to heat shock. ‘Dixiland’ peach fruits exposed to 39 °C, cold stored, or after a combined treatment of heat and cold, were compared with fruits ripening at 20 °C. Dramatic changes in the levels of compatible solutes such as galactinol and raffinose were observed, while amino acid precursors of the phenylpropanoid pathway were also modified due to the stress treatments, as was the polyamine putrescine. The observed responses towards temperature stress in peaches are composed of both common and specific response mechanisms to heat and cold, but also of more general adaptive responses that confer strategic advantages in adverse conditions such as biotic stresses. The identification of such key metabolites, which prime the fruit to cope with different stress situations, will likely greatly accelerate the design and the improvement of plant breeding programs.