Artículos (Instituto de Bioquímica Vegetal y Fotosíntesis IBVF – CIC Cartuja)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10949

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Phototropin connects blue light perception to starch metabolism in green algae
(Springer Nature, 2025-03-15) Yuan, Yizhong; Iannetta, Anthony A.; Kim, Minjae; Sadecki, Patric W.; Arend, Marius; Tsichla, Angeliki; Ruiz Sola, M. Águila; Kepesidis, Georgios; Petroutsos, Dimitris; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Human Frontiers Science Program; rench National Research Agency
In photosynthetic organisms, light acts as an environmental signal to control their development and physiology, as well as energy source to drive the conversion of CO2 into carbohydrates used for growth or storage. The main storage carbohydrate in green algae is starch, which accumulates during the day and is broken down at night to meet cellular energy demands. The signaling role of light quality in the regulation of starch accumulation remains unexplored. Here, we identify PHOTOTROPIN-MEDIATED SIGNALING KINASE 1 (PMSK1) as a key regulator of starch metabolism in Chlamydomonas reinhardtii. In its phosphorylated form (PMSK1-P), it activates GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAP1), promoting starch biosynthesis. We show that blue light, perceived by PHOTOTROPIN, induces PMSK1 dephosphorylation that in turn represses GAP1 mRNA levels and reduces starch accumulation. These findings reveal a previously uncharacterized blue light-mediated signaling pathway that advances our understanding of photoreceptor-controlled carbon metabolism in microalgae.
Engineering Inorganic Pyrophosphate Metabolism as a Strategy to Generate a Fluoride-Resistant Saccharomyces cerevisiae Strain
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Pérez Castiñeira, José Román; Ávila Oliva, F. J.; Serrano, A.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España
Fluorine accounts for 0.3 g/kg of the Earth’s crust, being widely distributed in the environment as fluoride. The toxic effects of this anion in humans and other organisms have been known for a long time. Fluoride has been reported to alter several cellular processes although the mechanisms involved are largely unknown. Inorganic pyrophosphatases (PPases) are ubiquitous enzymes that hydrolyze inorganic pyrophosphate (PPi), a metabolite generated from ATP. In Saccharomyces cerevisiae, the enzyme responsible for PPi hydrolysis in the cytosol (IPP1) is strongly inhibited by fluoride in vitro. The essentiality of IPP1 for growth has been previously demonstrated using YPC3, a yeast mutant with conditional expression of the corresponding gene. Here, YPC3 was used to generate cells that tolerate high concentrations of fluoride by (a) the overexpression of IPP1 or its human ortholog, or (b) the substitution of IPP1 by the fluoride-insensitive PPase from Streptococcus mutans. The results obtained suggest that maintaining appropriate levels of PPase activity in the cytosol is essential for the adaptation of S. cerevisiae to high fluoride concentrations. The increase in fluoride tolerance allows YPC3 cells transformed with suitable plasmids to be selected on rich non-selective medium supplemented with this anion.
Combined Effect of Temperature and Different Light Regimes on the Photosynthetic Activity and Lipid Accumulation in the Diatom Phaeodactylum tricornutum
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Díaz Santos, Encarnación; Heredia Martínez, Luis G.; López Maury, Luis; Hervás Morón, Manuel; Ortega Rodríguez, José María; Navarro, J. A.; Roncel Gil, Mercedes; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla; Junta de Andalucía
The aim of this study was to investigate the combined effects of temperature and light on the photosynthetic parameters and lipid accumulation in the diatom Phaeodactylum tricornutum, a model organism widely used for studies on diatom physiology, ecology, and biotechnology. Our results highlight the importance of the interaction between temperature and light intensity in influencing growth rates, pigments and active photosystems content, photosynthetic efficiency, lipid production and fatty acid composition in P. tricornutum. Measurements of the maximum electron transport rate (rETRmax) and rETR at maximum PAR (830 µmol m−2 s−1) confirmed that P. tricornutum exhibits significantly higher light sensitivity as growth temperature increases under light/dark cycles at two light intensities (25–60 µmol m−2 s−1). However, this trend was reversed under continuous light (25 µmol m−2 s−1). Moreover, higher rETRmax values (up to double) were observed at higher irradiance, either in intensity or under continuous light regimes, at the two temperatures tested. On the other hand, increasing light intensity amplified the observed effect of temperature on photosystem I (PSI) activity under light/dark regimes, but not under continuous light conditions. This resulted in a greater deficiency in PSI activity, likely due to limitations in electron supply to this photosystem. Furthermore, increasing the culture temperature from 20 °C to 25 °C triggered an increase in the number and size of cytoplasmic lipid droplets under conditions of increased light intensity, with an even more pronounced effect under continuous illumination. Notably, the combination of 25 °C and continuous illumination resulted in a more than twofold increase in triacylglyceride (TAG) content, reaching approximately 17 mg L−1. This condition also caused a substantial rise (up to ≈90%) in the proportions of palmitoleic and palmitic acids in the TAG fatty acid profile.
Transcriptomic analysis reveals the participation of NTRC in iron homeostasis in Arabidopsis
(Wiley, 2025-04-10) Rodríguez Marín, Fernando; Pérez Ruiz, Juan Manuel; Cejudo Fernández, Francisco Javier; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
NADPH-dependent thioredoxin reductase C (NTRC) plays a central role in redox regulation of chloroplast photosynthetic metabolism. Accordingly, Arabidopsis (Arabidopsis thaliana) NTRC-null mutants show defective photosynthetic performance and growth inhibition. Remarkably, these mutants show almost a wild-type phenotype at the seedling stage, which raises the question of whether NTRC plays different functions throughout plant development. In this work, we have addressed this issue by performing transcriptome comparisons of Arabidopsis wild-type and ntrc mutant lines at seedling and adult stages of development. In contrast with the high impact of NTRC on leaves from adult plants, the low transcriptomic differences in seedlings suggested a less relevant function of NTRC at this stage of plant development. Notably, the ntrc mutant showed transcriptomic changes resembling the response to Fe excess throughout plant development, though this response was almost unique at the seedling stage. The lack of NTRC caused altered levels of Mn, Zn, Cu, S, P, K and Na, but no significant differences in the content of Fe, as compared with the wild type. Moreover, at the seedling stage, the lack of NTRC caused hypersensitivity to Fe deficit but a protective effect in response to Fe excess, most likely due to lower ROS accumulation in the mutant seedlings. Our results reveal the different impacts of NTRC throughout plant development and identify Fe homeostasis as a process highly affected by NTRC, most notably at the seedling stage.
Antioxidant Responses and Redox Regulation Within Plant-Beneficial Microbe Interaction
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-12-18) González García, María de la Cruz; Roitsch, Thomas; Pandey, Chandana; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Novo Nordisk Foundation; Ministry of Education, Youth and Sports of the Czech Republic
The increase in extreme climate events associated with global warming is a great menace to crop productivity nowadays. In addition to abiotic stresses, warmer conditions favor the spread of infectious diseases affecting plant performance. Within this context, beneficial microbes constitute a sustainable alternative for the mitigation of the effects of climate change on plant growth and productivity. Used as biostimulants to improve plant growth, they also increase plant resistance to abiotic and biotic stresses through the generation of a primed status in the plant, leading to a better and faster response to stress. In this review, we have focused on the importance of a balanced redox status for the adequate performance of the plant and revisited the different antioxidant mechanisms supporting the biocontrol effect of beneficial microbes through the adjustment of the levels of reactive oxygen species (ROS). In addition, the different tools for the analysis of antioxidant responses and redox regulation have been evaluated. The importance of redox regulation in the activation of the immune responses through different mechanisms, such as transcriptional regulation, retrograde signaling, and post-translational modification of proteins, emerges as an important research goal for understanding the biocontrol activity of the beneficial microbes.
Transcriptomic characterization of the response to a microalgae extract in Arabidopsis thaliana and Solanum lycopersicum.
(2024-03-10) Arvanitidou, Christina; Rámos González, Marcos; Romero Losada, Ana Belen; García Gómez, María Elena; García González, Mercedes; Romero Campero, Francisco José; Universidad de Sevilla. Departamento de Ciencias de la Computación e Inteligencia Artificial; Ministerio de Ciencia e Innovación (MICIN). España
BACKGROUND: The steady world population growth and the current climate emergency crisis demand the development of sus- tainable methods to increase crop performance and resilience to the abiotic and biotic stresses produced by global warming. Microalgal extracts are being established as sustainable sources to produce compounds that improve agricultural yield, concur- rently contributing during their production process to atmospheric CO 2 abatement through the photosynthetic activity of microalgae. RESULTS: In the present study, we characterize the transcriptomic response in the model plant Arabidopsis thaliana and the plant of horticultural interest Solanum lycopersicum to the foliar application of a microalgae-based commercial preparation LRM™ (AlgaEnergy, Madrid, Spain). The foliar spray of LRM™ has a substantial effect over both transcriptomes potentially medi- ated by various compounds within LRM™, including its phytohormone content, activating systemic acquired resistance, possi- bly mediated by salicylic acid biosynthetic processes, and drought/heat acclimatization, induced by stomatal control and wax accumulation during cuticle development. Speciﬁcally, the agronomic improvements observed in treated S. lycopersicum (tomato) plants include an increase in the number of fruits, an acceleration in ﬂowering time and the provision of higher drought resistance. The effect of LRM™ foliar spray in juvenile and adult plants was similar, producing a fast response detect- able 2 h from its application that was also maintained 24 h later. CONCLUSION: The present study improves our knowledge on the transcriptomic effect of a novel microalgal extract on crops and provides the ﬁrst step towards a full understanding of the yield and resistance improvement of crops. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Seed longevity is controlled by metacaspases
(Nature Research, 2024-08-08) Liu, Chen; Hatzianestis, Ioannis H.; Pfirrmann, Thorsten; Reza, Salim H.; Minina, Elena A.; Moazzami, Ali; Gutiérrez Beltrán, Emilio; Romero Campero, Francisco José; Moschou, Panagiotis N.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; European Union (UE). H2020; European Research Council (ERC)
To survive extreme desiccation, seeds enter a period of quiescence that can last millennia. Seed quiescence involves the accumulation of protective storage proteins and lipids through unknown adjustments in protein homeostasis (proteostasis). Here, we show that mutation of all six type–II metacaspase (MCA–II) proteases in Arabidopsis thaliana disturbs proteostasis in seeds. MCA–II mutant seeds fail to restrict the AAA ATPase CELL DIVISION CYCLE 48 (CDC48) at the endoplasmic reticulum to discard misfolded proteins, compromising seed storability. Endoplasmic reticulum (ER) localization of CDC48 relies on the MCA–IIs-dependent cleavage of PUX10 (ubiquitination regulatory X domain–containing 10), the adaptor protein responsible for titrating CDC48 to lipid droplets. PUX10 cleavage enables the shuttling of CDC48 between lipid droplets and the ER, providing an important regulatory mechanism sustaining spatiotemporal proteolysis, lipid droplet dynamics, and protein homeostasis. In turn, the removal of the PUX10 adaptor in MCA–II mutant seeds partially restores proteostasis, CDC48 localization, and lipid droplet dynamics prolonging seed lifespan. Taken together, we uncover a proteolytic module conferring seed longevity
R-DeeP/TripepSVM identifies the RNA-binding OB-fold-like protein PatR as regulator of heterocyst patterning
(Oxford University Press, 2025-02-10) Brenes-Álvarez, Manuel; Ropp, Halie R.; Papagiannidis, Dimitrios; Potel, Clement M.; Stein, Frank; Scholz, Ingeborg; Steglich, Claudia; Savitski, Mikhail M.; Vioque Peña, Agustín; Muro Pastor, Alicia María; Hess, Wolfgang R.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Deutsche Forschungsgemeinschaft / German Research Foundation (DFG); Ministerio de Ciencia e Innovación (MICIN). España
RNA-binding proteins (RBPs) are central components of gene regulatory networks. The differentiation of heterocysts in filamentous cyanobacteria is an example of cell differentiation in prokaryotes. Although multiple non-coding transcripts are involved in this process, no RBPs have been implicated thus far. Here we used quantitative mass spectrometry to analyze the differential fractionation of RNA–protein complexes after RNase treatment in density gradients yielding 333 RNA-associated proteins, while a bioinformatic prediction yielded 311 RBP candidates in Nostoc sp. PCC 7120. We validated in vivo the RNA-binding capacity of six RBP candidates. Some participate in essential physiological aspects, such as photosynthesis (Alr2890), thylakoid biogenesis (Vipp1) or heterocyst differentiation (PrpA, PatU3), but their association with RNA was unknown. Validated RBPs Asl3888 and Alr1700 were not previously characterized. Alr1700 is an RBP with two oligonucleotide/oligosaccharide-binding (OB)-fold-like domains that is differentially expressed in heterocysts and interacts with non-coding regulatory RNAs. Deletion of alr1700 led to complete deregulation of the cell differentiation process, a striking increase in the number of heterocyst-like cells, and was ultimately lethal in the absence of combined nitrogen. These observations characterize this RBP as a master regulator of the heterocyst patterning and differentiation process, leading us to rename Alr1700 to PatR.
Mutational analysis of the inactivating factors, IF7 and IF17 from Synechocystis sp. PCC 6803: Critical role of arginine amino acid residues for glutamine synthetase inactivation
(John Wiley & Sons, 2011-11) Saelices, Lorena; Galmozzi, Carla V.; Florencio Bellido, Francisco Javier; Muro Pastor, María Isabel; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
The Synechocystis sp. PCC 6803 glutamine synthetase type I (GS) activity is controlled by a process that involves protein-protein interaction with two inactivating factors (IF7 and IF17). IF7 is a natively unfolded, 65-residue-long protein, homologous to the carboxy-terminal region of IF17. Both proteins have abundance of positively charged amino acid residues and a high isoelectric point. In this study, we analyse the IF amino acid residues involved in GS inactivation by a mutational approach, both in vitro and in vivo. The results clearly indicate that the GS-IF complex formation must be determined mainly by electrostatic interactions. We have identified three conserved arginine residues of IF7 and IF17 that are essential for the interaction of these proteins with GS. All these residues map in the homologous region of IFs. Furthermore, in vitro analysis of a truncated IF17 protein without the 82-residue-long amino-terminal part, together with the analysis of a Synechocystis strain expressing a chimeric protein, containing this amino-terminal part of IF17 fused to IF7, demonstrates that amino-terminal region of IF17 mostly confers a higher stability to this protein.
The inactivating factor of glutamine synthetase IF17 Is an intrinsically disordered protein, which folds upon binding to its target
(American Chemical Society, 2011-10-12) Saelices, Lorena; Galmozzi, Carla V.; Florencio Bellido, Francisco Javier; Muro Pastor, María Isabel; Neira, José L.; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Generalitat Valenciana; Junta de Andalucía
In cyanobacteria, ammonium is incorporated into carbon skeletons by the sequential action of glutamine synthetase and glutamate synthase (GOGAT). The activity of Synechocystis sp. PCC 6803 glutamine synthetase type I (GS) is controlled by a post-transcriptional process involving protein-protein interactions with two inactivating factors: the 65-residue-long protein (IF7) and the 149-residue-long one (IF17). The sequence of the C terminus of IF17 is similar to IF7; IF7 is an intrinsically disordered protein (IDP). In this work, we study the structural propensities and affinity for GS of IF17 and a chimera protein, IF17N/IF7 (constructed by fusing the first 82 residues of IF17 with the whole IF7) by fluorescence, CD, and NMR. IF17 and IF17N/IF7 are IDPs with residual non-hydrogen-bonded structure, probably formed by α-helical, turn-like, and PPII conformations; several theoretical predictions support these experimental findings. IF17 seems to fold upon binding to GS, as suggested by CD thermal denaturations and steady-state far-UV spectra. The apparent affinity of IF17 for GS, as measured by fluorescence, is slightly smaller (K D ∼1 μM) than that measured for IF7 (∼0.3 μM). The K Ds determined by CD are similar to those measured by fluorescence, but slightly larger, suggesting possible conformational rearrangements in the IFs and/or GS upon binding. Further, the results with IFN17/IF7 suggest that (i) binding of IF17 to the GS is modulated not only by its C-terminal region but also by its N-terminus and (ii) there are weakly structured (that is, "fuzzy") complexes in the ternary GS-IF system.
Functional dissection and evidence for intercellular transfer of the heterocyst-differentiation PatS morphogen
(John Wiley & Sons, 2013-06) Corrales Guerrero, Laura; Mariscal Romero, Vicente; Flores, Enrique; Herrero, Antonia; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España
The formation of a diazotrophic cyanobacterial filament represents a simple example of biological development. In Anabaena, a non-random pattern of one nitrogen-fixing heterocyst separated by about 10 photosynthetic vegetative cells results from lateral inhibition elicited by the cells differentiating into heterocysts. Key to this process is the patS gene, which has been shown to produce an inhibitor of heterocyst differentiation that involves the C-terminal RGSGR pentapeptide. Complementation of a ΔpatSAnabaena mutant with different versions of PatS, including point mutations or tag fusions, showed that patS is translated into a 17-amino acid polypeptide. Alterations in the N-terminal part of PatS produced inhibition of heterocyst differentiation, thus this part of the peptide appears necessary for proper processing and self-immunity in the producing cells. Alterations in the C-terminal part of PatS led to over-differentiation, thus supporting its role in inhibition of heterocyst differentiation. A polypeptide, produced in proheterocysts, consisting of a methionine followed by the eight, but not the five, terminal amino acids of PatS recreated the full activity of the native peptide. Immunofluorescence detection showed that an RGSGR-containing peptide accumulated in the cells adjacent to the producing proheterocysts, illustrating intercellular transfer of a morphogen in the cyanobacterial filaments.
Photoperiodic Signaling and Senescence, an Ancient Solution to a Modern Problem?
(Frontiers, 2021-03-10) Serrano Bueno, Gloria; Sánchez de Medina Hernández, Victor; Valverde Albacete, Federico; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Educación y Ciencia (MEC). España; European Union (UE)
The length of the day (photoperiod) is a robust seasonal signal originated by earth orbital and translational movements, a resilient external cue to the global climate change, and a predictable hint to initiate or complete different developmental programs. In eukaryotic algae, the gene expression network that controls the cellular response to photoperiod also regulates other basic physiological functions such as starch synthesis or redox homeostasis. Land plants, evolving in a novel and demanding environment, imbued these external signals within the regulatory networks controlling organogenesis and developmental programs. Unlike algae that largely have to deal with cellular physical cues, within the course of evolution land plants had to transfer this external information from the receiving organs to the target tissues, and mobile signals such as hormones were recruited and incorporated in the regulomes. Control of senescence by photoperiod, as suggested in this perspective, would be an accurate way to feed seasonal information into a newly developed function (senescence) using an ancient route (photoperiodic signaling). This way, the plant would assure that two coordinated aspects of development such as flowering and organ senescence were sequentially controlled. As in the case of senescence, there is growing evidence to support the idea that harnessing the reliability of photoperiod regulation over other, more labile signaling pathways could be used as a robust breeding tool to enhance plants against the harmful effects of climate change.
Persulfidome of Sweet Pepper Fruits during Ripening: The Case Study of Leucine Aminopeptidase That Is Positively Modulated by H2S
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Muñoz Vargas, M. A.; González Gordo, S.; Aroca Aguilar, Ángeles; Romero, L. C.; Gotor, C.; Palma, J. M.; Corpas, F. J.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España
Protein persulfidation is a thiol-based oxidative posttranslational modification (oxiPTM) that involves the modification of susceptible cysteine thiol groups present in peptides and proteins through hydrogen sulfide (H2S), thus affecting their function. Using sweet pepper (Capsicum annuum L.) fruits as a model material at different stages of ripening (immature green and ripe red), endogenous persulfidated proteins (persulfidome) were labeled using the dimedone switch method and identified using liquid chromatography and mass spectrometry analysis (LC-MS/MS). A total of 891 persulfidated proteins were found in pepper fruits, either immature green or ripe red. Among these, 370 proteins were exclusively present in green pepper, 237 proteins were exclusively present in red pepper, and 284 proteins were shared between both stages of ripening. A comparative analysis of the pepper persulfidome with that described in Arabidopsis leaves allowed the identification of 25% of common proteins. Among these proteins, glutathione reductase (GR) and leucine aminopeptidase (LAP) were selected to evaluate the effect of persulfidation using an in vitro approach. GR activity was unaffected, whereas LAP activity increased by 3-fold after persulfidation. Furthermore, this effect was reverted through treatment with dithiothreitol (DTT). To our knowledge, this is the first persulfidome described in fruits, which opens new avenues to study H2S metabolism. Additionally, the results obtained lead us to hypothesize that LAP could be involved in glutathione (GSH) recycling in pepper fruits.
Antisense RNA Regulates Glutamine Synthetase in a Heterocyst-forming Cyanobacterium
(American Society of Plant Biologists, 2024) Álvarez Escribano, Isidro; Suárez Murillo, Belén; Brenes Álvarez, Manuel; Vioque Peña, Agustín; Muro Pastor, Alicia M.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
Glutamine synthetase (GS) is a key enzyme involved in nitrogen assimilation and the maintenance of C/N balance, and it is strictly regulated in all bacteria. In cyanobacteria, GS expression is controlled by nitrogen control A (NtcA) transcription factor, which operates global nitrogen regulation in these photosynthetic organisms. Furthermore, posttranslational regulation of GS is operated by protein–protein interaction with GS inactivating factors (IFs). In this study, we describe an additional regulatory mechanism involving an antisense RNA. In Nostoc sp. PCC 7120, the gifA gene (encoding GS inactivating factor IF7) is transcribed downstream of the GS (glnA) gene, from the opposite strand, and the gifA mRNA extends into the glnA coding sequence in antisense orientation. Therefore, the dual RNA transcript that encodes gifA constitutes two functional regions: a 5′ protein-coding region, encoding IF7, and a 3′ untranslated region that acts as an antisense to glnA. By increasing the levels of such antisense RNA either in cis or in trans, we demonstrate that the amount of GS activity can be modulated by the presence of the antisense RNA. The tail-to-tail disposition of the glnA and gifA genes observed in many cyanobacterial strains from the Nostocales clade suggests the prevalence of such antisense RNA-mediated regulation of GS in this group of cyanobacteria.
Direct Interaction between Marine Cyanobacteria Mediated by Nanotubes
(American Association for the Advancement of Science, 2024) Angulo Cánovas, Elisa; Bartual, Ana; López Igual, Rocío; Luque, Ignacio; Radzinski, Nikolai P.; Shilova, Irina; Anjur Dietrich, Maya; García Jurado, Gema; Úbeda, Bárbara; González Reyes, José Antonio; Muñoz Marín, María del Carmen; Universidad de Sevilla. Departamento de Bioquímica y Biología Molecular; Gobierno de España; Ministerio de Ciencia e Innovación (MICIN). España; Simons Foundation Life Sciences; SCOPE Award; Simons Postdoctoral Fellowship in Marine Microbial Ecology; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Frontier Projects
Microbial associations and interactions drive and regulate nutrient fluxes in the ocean. However, physical contact between cells of marine cyanobacteria has not been studied thus far. Here, we show a mechanism of direct interaction between the marine cyanobacteria Prochlorococcus and Synechococcus, the intercellular membrane nanotubes. We present evidence of inter-and intra-genus exchange of cytoplasmic material between neighboring and distant cells of cyanobacteria mediated by nanotubes. We visualized and measured these structures in xenic and axenic cultures and in natural samples. We show that nanotubes are produced between living cells, suggesting that this is a relevant system of exchange material in vivo. The discovery of nanotubes acting as exchange bridges in the most abundant photosynthetic organisms in the ocean may have important implications for their interactions with other organisms and their population dynamics.
Analysis of sulfide signaling in rice highlights specific drought responses
(Oxford University Press, 2024-08-28) Zhang, Jing; Aroca Aguilar, Ángeles; Hervás Morón, Manuel; Navarro, José A.; Moreno, Inmaculada; Xie, Yanjie; Romero, Luis C.; Gotor Martínez, Cecilia; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Consejo Superior de Investigaciones Científicas (CSIC); Junta de Andalucía
Hydrogen sulfide regulates essential plant processes, including adaptation responses to stress situations, and the best characterized mechanism of action of sulfide consists of the post-translational modification of persulfidation. In this study, we reveal the first persulfidation proteome described in rice including 3443 different persulfidated proteins that participate in a broad range of biological processes and metabolic pathways. In addition, comparative proteomics revealed specific proteins involved in sulfide signaling during drought responses. Several proteins are involved in the maintenance of cellular redox homeostasis, the tricarboxylic acid cycle and energy-related pathways, and ion transmembrane transport and cellular water homeostasis, with the aquaporin family showing the highest differential levels of persulfidation. We revealed that water transport activity is regulated by sulfide which correlates with an increasing level of persulfidation of aquaporins. Our findings emphasize the impact of persulfidation on total ATP levels, fatty acid composition, levels of reactive oxygen species, antioxidant enzymatic activities, and relative water content. Interestingly, the role of persulfidation in aquaporin transport activity as an adaptation response in rice differs from current knowledge of Arabidopsis, which highlights the distinct role of sulfide in improving rice tolerance to drought.
Comparative Genomics of Synechococcus elongatus Explains the Phenotypic Diversity of the Strains
(American Society for Microbiology, 2022) Adomako, Marie; Ernst, Dustin; Simkovsky, Ryan; Chao, Yi Yun; Wang, Jingtong; Fang, Mingxu; Bouchier, Christiane; López Igual, Rocío; Mazel, Didier; Gugger, Muriel; Golden, Susan S.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; National Institutes of Health. United States
Strains of the freshwater cyanobacterium Synechococcus elongatus were first isolated approximately 60 years ago, and PCC 7942 is well established as a model for photosynthesis, circadian biology, and biotechnology research. The recent isolation of UTEX 3055 and subsequent discoveries in biofilm and phototaxis phenotypes suggest that lab strains of S. elongatus are highly domesticated. We performed a comprehensive genome comparison among the available genomes of S. elongatus and sequenced two additional laboratory strains to trace the loss of native phenotypes from the standard lab strains and determine the genetic basis of useful phenotypes. The genome comparison analysis provides a pangenome description of S. elongatus, as well as correction of extensive errors in the published sequence for the type strain PCC 6301. The comparison of gene sets and single nucleotide polymorphisms (SNPs) among strains clarifies strain isolation histories and, together with large-scale genome differences, supports a hypothesis of laboratory domestication. Prophage genes in laboratory strains, but not UTEX 3055, affect pigmentation, while unique genes in UTEX 3055 are necessary for phototaxis. The genomic differences identified in this study include previously reported SNPs that are, in reality, sequencing errors, as well as SNPs and genome differences that have phenotypic consequences. One SNP in the circadian response regulator rpaA that has caused confusion is clarified here as belonging to an aberrant clone of PCC 7942, used for the published genome sequence, that has confounded the interpretation of circadian fitness research.
An Actin Remodeling Role for Arabidopsis Processing Bodies Revealed by their Proximity Interactome
(WILEY, 2023) Liu, Chen; Mentzelopoulou, Andriani; Muhammad, Amna; Volkov, Andriy; Weijers, Dolf; Gutiérrez Beltrán, Emilio; Moschou, Panagiotis N.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Carl Tryggers Foundation; European Union (UE); Vetenskapsradet (VR) research council; FORMAS research council; Helge Ax:son Johnsons stiftelse; Hellenic Foundation of Research and Innovation (HFRI); European Research Council (ERC); Ministerio de Ciencia e Innovación (MICIN). España
Cellular condensates can comprise membrane-less ribonucleoprotein assemblies with liquid-like properties. These cellular condensates influence various biological outcomes, but their liquidity hampers their isolation and characterization. Here, we investigated the composition of the condensates known as processing bodies (PBs) in the model plant Arabidopsis thaliana through a proximity-biotinylation proteomics approach. Using in situ protein–protein interaction approaches, genetics and high-resolution dynamic imaging, we show that processing bodies comprise networks that interface with membranes. Surprisingly, the conserved component of PBs, DECAPPING PROTEIN 1 (DCP1), can localize to unique plasma membrane subdomains including cell edges and vertices. We characterized these plasma membrane interfaces and discovered a developmental module that can control cell shape. This module is regulated by DCP1, independently from its role in decapping, and the actin-nucleating SCAR–WAVE complex, whereby the DCP1–SCAR–WAVE interaction confines and enhances actin nucleation. This study reveals an unexpected function for a conserved condensate at unique membrane interfaces.
Emerging nitrogen-fixing cyanobacteria for sustainable cotton cultivation
(Elsevier, 2024-05-10) Jiménez Ríos, Lucía; Torrado Maya, Alejandro; González Pimentel, José Luis; Iniesta Pallarés, Macarena; Molina Heredia, Fernando Publio; Mariscal, Vicente; Álvarez Núñez, Consolación; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Corporación Tecnológica de Andalucía; Junta de Andalucía
Amid growing environmental concerns and the imperative for sustainable agricultural practices, this study examines the potential of nitrogen-fixing cyanobacteria as biofertilizers, particularly in cotton cultivation. The reliance on synthetic nitrogen fertilizers (SNFs), prevalent in modern agriculture, poses significant environmental challenges, including greenhouse gas emissions and water system contamination. This research aims to shift this paradigm by exploring the capacity of cyanobacteria as a natural and sustainable alternative. Utilizing advanced metabarcoding methods to analyze the 16S rRNA gene, we conducted a comprehensive assessment of soil bacterial communities within cotton fields. This study focused on evaluating the diversity, structure, taxonomic composition, and potential functional characteristics of these communities. Emphasis was placed on the isolation of native N2-fixing cyanobacteria strains rom cotton soils, and their subsequent effects on cotton growth. Results from our study demonstrate significant plant growth-promoting (PGP) activities, measured as N2 fixation, production of Phytohormones, Fe solubilization and biofertilization potential of five isolated cyanobacterial strains, underscoring their efficacy in cotton. These findings suggest a viable pathway for replacing chemical-synthetic nitrogen fertilizers with natural, organic alternatives. The reintegration of these beneficial species into agricultural ecosystems can enhance crop growth while fostering a balanced microbial environment, thus contributing to the broader goals of global sustainable agriculture.
The Functional Relationship between NADPH Thioredoxin Reductase C, 2-Cys Peroxiredoxins, and m-Type Thioredoxins in the Regulation of Calvin–Benson Cycle and Malate-Valve Enzymes in Arabidopsis
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-05-03) Delgado Requerey, Víctor; Cejudo Fernández, Francisco Javier; González García, María de la Cruz; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
The concerted regulation of chloroplast biosynthetic pathways and NADPH extrusion via malate valve depends on f and m thioredoxins (Trxs). The finding that decreased levels of the thiol-peroxidase 2-Cys peroxiredoxin (Prx) suppress the severe phenotype of Arabidopsis mutants lacking NADPH-dependent Trx reductase C (NTRC) and Trxs f uncovered the central function of the NTRC-2-Cys-Prx redox system in chloroplast performance. These results suggest that Trxs m are also regulated by this system; however, the functional relationship between NTRC, 2-Cys Prxs, and m-type Trxs is unknown. To address this issue, we generated Arabidopsis thaliana mutants combining deficiencies in NTRC, 2-Cys Prx B, Trxs m1, and m4. The single trxm1 and trxm4 mutants showed a wild-type phenotype, growth retardation being noticed only in the trxm1m4 double mutant. Moreover, the ntrc-trxm1m4 mutant displayed a more severe phenotype than the ntrc mutant, as shown by the impaired photosynthetic performance, altered chloroplast structure, and defective light-dependent reduction in the Calvin–Benson cycle and malate-valve enzymes. These effects were suppressed by the decreased contents of 2-Cys Prx, since the quadruple ntrc-trxm1m4-2cpb mutant displayed a wild-type-like phenotype. These results show that the activity of m-type Trxs in the light-dependent regulation of biosynthetic enzymes and malate valve is controlled by the NTRC-2-Cys-Prx system.

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