Mobile forms of carbon in trees: metabolism and transport

Plants constitute 80% of the biomass on earth, and almost two-thirds of this biomass is found in wood. Wood formation is a carbon (C)-demanding process and relies on C transport from photosynthetic tissues. Thus, understanding the transport process is of major interest for understanding terrestrial biomass formation. Here, we review the molecules and mechanisms used to transport and allocate C in trees. Sucrose is the major form in which C is transported in plants, and it is found in the phloem sap of all tree species investigated so far. However, in several tree species, sucrose is accompanied by other molecules, notably polyols and the raffinose family of oligosaccharides. We describe the molecules that constitute each of these transport groups, and their distribution across different tree species. Furthermore, we detail the metabolic reactions for their synthesis, the mechanisms by which trees load and unload these compounds in and out of the vascular system, and how they are radially transported in the trunk and finally catabolized during wood formation. We also address a particular C recirculation process between phloem and xylem that occurs in trees during the annual cycle of growth and dormancy. A search of possible evolutionary drivers behind the diversity of C-carrying molecules in trees reveals no consistent differences in C transport mechanisms between angiosperm and gymnosperm trees. Furthermore, the distribution of C forms across species suggests that climate-related environmental factors will not explain the diversity of C transport forms. However, the consideration of C-transport mechanisms in relation to tree-rhizosphere coevolution deserves further attention. To conclude the review, we identify possible future lines of research in this field.Fil: Dominguez, Pia Guadalupe. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Niittylä, Totte. Swedish University of Agricultural Sciences; Sueci

Mobile forms of carbon in trees: metabolism and transport

Plants constitute 80% of the biomass on earth, and almost two-thirds of this biomass is found in wood. Wood formation is a carbon (C)-demanding process and relies on C transport from photosynthetic tissues. Thus, understanding the transport process is of major interest for understanding terrestrial biomass formation. Here, we review the molecules and mechanisms used to transport and allocate C in trees. Sucrose is the major form in which C is transported in plants, and it is found in the phloem sap of all tree species investigated so far. However, in several tree species, sucrose is accompanied by other molecules, notably polyols and the raffinose family of oligosaccharides. We describe the molecules that constitute each of these transport groups, and their distribution across different tree species. Furthermore, we detail the metabolic reactions for their synthesis, the mechanisms by which trees load and unload these compounds in and out of the vascular system, and how they are radially transported in the trunk and finally catabolized during wood formation. We also address a particular C recirculation process between phloem and xylem that occurs in trees during the annual cycle of growth and dormancy. A search of possible evolutionary drivers behind the diversity of C-carrying molecules in trees reveals no consistent differences in C transport mechanisms between angiosperm and gymnosperm trees. Furthermore, the distribution of C forms across species suggests that climate-related environmental factors will not explain the diversity of C transport forms. However, the consideration of C-transport mechanisms in relation to tree-rhizosphere coevolution deserves further attention. To conclude the review, we identify possible future lines of research in this field

Multiomics analyses reveal the roles of the ASR1 transcription factor in tomato fruits

The transcription factor ASR1 (ABA, STRESS, RIPENING 1) plays multiple roles in plant responses to abiotic stresses as well as being involved in the regulation of central metabolism in several plant species. However, despite the high expression of ASR1 in tomato fruits, large scale analyses to uncover its function in fruits are still lacking. In order to study its function in the context of fruit ripening, we performed a multiomics analysis of ASR1-antisense transgenic tomato fruits at the transcriptome and metabolome levels. Our results indicate that ASR1 is involved in several pathways implicated in the fruit ripening process, including cell wall, amino acid, and carotenoid metabolism, as well as abiotic stress pathways. Moreover, we found that ASR1-antisense fruits are more susceptible to the infection by the necrotrophic fungus Botrytis cinerea. Given that ASR1 could be regulated by fruit ripening regulators such as FRUITFULL1/FRUITFULL2 (FUL1/FUL2), NON-RIPENING (NOR), and COLORLESS NON-RIPENING (CNR), we positioned it in the regulatory cascade of red ripe tomato fruits. These data extend the known range of functions of ASR1 as an important auxiliary regulator of tomato fruit ripening.Fil: Dominguez, Pia Guadalupe. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Conti, Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; Argentina. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Duffy, Tomás. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Insani, Ester Marina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Alseekh, Saleh. Max Planck Institute of Molecular Plant Physiology; Alemania. Center Of Plant Systems Biology And Biotechnology; BulgariaFil: Asurmendi, Sebastian. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Fernie, Alisdair R. Max Planck Institute of Molecular Plant Physiology; Alemania. Center Of Plant Systems Biology And Biotechnology; BulgariaFil: Carrari, Fernando Oscar. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Natural occurring epialleles determine vitamin E accumulation in tomato fruits

Vitamin E (VTE) content is a low heritability nutritional trait for which the genetic determinants are poorly understood. Here, we focus on a previously detected major tomato VTE quantitative trait loci (QTL; mQTL9-2-6) and identify the causal gene as one encoding a 2-methyl-6-phytylquinol methyltransferase (namely VTE3(1)) that catalyses one of the final steps in the biosynthesis of γ- and α-tocopherols, which are the main forms of VTE. By reverse genetic approaches, expression analyses, siRNA profiling and DNA methylation assays, we demonstrate that mQTL9-2-6 is an expression QTL associated with differential methylation of a SINE retrotransposon located in the promoter region of VTE3(1). Promoter DNA methylation can be spontaneously reverted leading to different epialleles affecting VTE3(1) expression and VTE content in fruits. These findings indicate therefore that naturally occurring epialleles are responsible for regulation of a nutritionally important metabolic QTL and provide direct evidence of a role for epigenetics in the determination of agronomic traits.L.Q. was recipient of a fellowship of Agencia Nacional de Promoción Científica y Tecnológica and Consejo Nacional de Investigaciones Científicas y Técnicas in Argentina and supported by a postdoctral fellowship from Investissements d’Avenir ANR-10-LABX-54 MEMO LIFE in France. J.A. and L.B. were recipients of a fellowship of Fundação à Amparo da Pesquisa do Estado de São Paulo (Brazil). J.V.C.d.S. was recipient of a fellowship of Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil). R.A., L.B. and F.C. are members of Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina). This work was carried out in compliance with current laws governing genetic experimentation in Brazil and in Argentina. This work was supported with grants from Instituto Nacional de Tecnologia Agropecuária, Consejo Nacional de Investigaciones Científicas y Técnicas and Agencia Nacional de Promoción Científica y Tecnológica (Argentina), Fundação à Amparo da Pesquisa do Estado de São Paulo, Conselho Nacional de Desenvolvimento Científico e Tecnológico and Universidade de São Paulo (Brazil); Max Planck Society (Germany); the Agence Nationale de la Recherche (Investissements d’Avenir ANR-10-LABX-54 MEMO LIFE and ANR-11-IDEX-0001-02 PSL* Research University to V.C.); and the European Union (EpiGeneSys FP7 Network of Excellence number 257082 to V.C. and the European Solanaceae Integrated Project FOOD-CT-2006-016214 to F.C., M.R. and A.R.F.)

Genome-wide data (ChIP-seq) enabled identification of cell wall-related and aquaporin genes as targets of tomato ASR1, a drought stress-responsive transcription factor

Background: Identifying the target genes of transcription factors is important for unraveling regulatory networks in all types of organisms. Our interest was precisely to uncover the spectrum of loci regulated by a widespread plant transcription factor involved in physiological adaptation to drought, a type of stress that plants have encountered since the colonization of land habitats 400 MYA. The regulator under study, named ASR1, is exclusive to the plant kingdom (albeit absent in Arabidopsis) and known to alleviate the stress caused by restricted water availability. As its target genes are still unknown despite the original cloning of Asr1 cDNA 20 years ago, we examined the tomato genome for specific loci interacting in vivo with this conspicuous protein. Results: We performed ChIP followed by high throughput DNA sequencing (ChIP-seq) on leaves from stressed tomato plants, using a high-quality anti-ASR1 antibody. In this way, we unraveled a novel repertoire of target genes, some of which are clearly involved in the response to drought stress. Many of the ASR1-enriched genomic loci we found encode enzymes involved in cell wall synthesis and remodeling as well as channels implicated in water and solute flux, such as aquaporins. In addition, we were able to determine a robust consensus ASR1-binding DNA motif.Conclusions: The finding of cell wall synthesis and aquaporin genes as targets of ASR1 is consistent with their suggested role in the physiological adaptation of plants to water loss. The results gain insight into the environmental stress-sensing pathways leading to plant tolerance of drought. © 2014 Ricardi et al.; licensee BioMed Central Ltd.Fil: Ricardi, Martiniano María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: González, Rodrigo Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Zhong, Silin. Boyce Thompson Institute For Plant Research;Fil: Dominguez, Pia Guadalupe. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Duffy, Tomás. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Turjanski, Pablo Guillermo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Salgado Salter, Juan David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Alleva, Karina Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Carrari, Fernando Oscar. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Giovannoni, James J.. Cornell University; Estados UnidosFil: Estevez, Jose Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Iusem, Norberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Análisis funcional del factor de transcripción ASR1 desde una perspectiva metabólica, fisiológica y molecular en plantas de tabaco y tomate

Tesis para obtener el grado de Doctora en Farmacia y Bioquímica en Biología Molecular, de la Universidad de Buenos Aires, en 2014La familia de genes Asr (ABA, stress, ripening) está implicada en las vías de respuestas generales a estrés y en el control del transporte de hexosas. Para profundizar en el estudio funcional del parálogo ASR1 en Solanáceas, se evaluaron plantas de tabaco y tomate que sobreexpresan y silencian Asr1 desde una perspectiva metabólica, fisiológica y molecular. El estudio de las plantas de tabaco silenciadas mostró que tienen alteraciones en los niveles foliares de glucosa así como disminuciones en los niveles de expresión del transportador de hexosas Ht1. Asimismo, esas mismas plantas muestran modificaciones en los niveles de las hormonas ABA y giberelinas. Por el contrario, el principal efecto metabólico observado en los frutos de tomate es a nivel del metabolismo de los aminoácidos. Los niveles de expresión de los genes asociados a vías de respuesta frente a estrés en los frutos de las líneas silenciadas sugieren que ASR1 reprime esas vías en esos tejidos. Asimismo se encontraron evidencias que indican que ASR1 estaría relacionado con el metabolismo de la pared celular y con la vía de las citoquininas en los frutos de tomate. En conclusión, ASR1 está involucrado en el metabolismo primario, hormonal y en vías de respuesta a estrés en las Solanáceas estudiadas.The Asr (ABA, stress, ripening) gene family is involved in the general stress response pathways and in the control of hexose transport. To functionally study the paralogue ASR1 in Solanaceae, over-expressing and silenced tobacco and tomato plants were evaluated from a metabolic, physiological and molecular perspective. Silenced tobacco plants show alterations in leaf glucose levels and in the hexose transporter Ht1 mRNA levels. These plants also show alterations in ABA and gibberellin levels. On the contrary, the main metabolic effect in tomato fruits is on the amino acid metabolism. The expression levels of the genes related to the stress response pathway in the tomato fruits of the silenced lines suggest that ASR1 represses that pathway in that tissue. Evidence also shows that ASR1 is involved in the cell wall metabolism and in the cytokinin pathway in tomato fruits. In conclusion, ASR1 is involved in the primary metabolism and in the hormonal and stress response pathways in the studied Solanaceae.Instituto de BiotecnologíaFil: Dominguez, Pia Guadalupe. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentin

ASR1 transcription factor and its role in metabolism

Asr1 (ABA, stress, ripening) is a plant gene widely distributed in many species which was discovered by differential induction levels in tomato plants subjected to drought stress conditions. ASR1 also regulates the expression of a hexose transporter in grape and is involved in sugar and amino acid accumulation in some species like maize and potato. The control that ASR1 exerts on hexose transport is interesting from a biotechnological perspective because both sugar partitioning and content in specific organs affect the yield and the quality of many agronomically important crops. ASR1 affect plant metabolism by its dual activity as a transcription factor and as a chaperone-like protein. In this paper, we review possible mechanisms by which ASR1 affects metabolism, the differences observed among tissues and species, and the possible physiological implications of its role in metabolism.Instituto de BiotecnologíaFil: Dominguez, Pia Guadalupe. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carrari, Frenando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin