RESUMEN
In an attempt to address the large inequities faced by the plant biology communities from the Global South (i.e. countries located around the tropics and the Southern Hemisphere) at international conferences, this Viewpoint is the reflexive thinking arising from the concurrent session titled 'Arabidopsis and its translational research in the Global South' organized at the International Conference of Arabidopsis Research 2023 (ICAR 2023) in Chiba, Japan in June 2023. Here, we highlight the main obstacles plant biology communities in the Global South face in terms of knowledge production, as measured by the unequal production and citation of publications, investigating and advancing local plant genomics and biodiversity, combating disparities in gender and diversity, and current initiatives to break isolation of scientists.
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Investigación , Arabidopsis/genética , Arabidopsis/fisiología , Biodiversidad , Botánica , Plantas/genéticaAsunto(s)
Proteínas de Arabidopsis , Arabidopsis , Relojes Circadianos , Proteínas de Unión al ADN , Fotoperiodo , Factores de Transcripción , Arabidopsis/fisiología , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Relojes Circadianos/fisiología , Factores de Transcripción/metabolismo , Proteínas de Unión al ADN/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
BACKGROUND: Common bean (Phaseolus vulgaris) is one of the main nutritional resources in the world, and a low environmental impact source of protein. However, the majority of its cultivation areas are affected by drought and this scenario is only expected to worsen with climate change. Stomatal closure is one of the most important plant responses to drought and the MYB60 transcription factor is among the key elements regulating stomatal aperture. If targeting and mutating the MYB60 gene of common bean would be a valuable strategy to establish more drought-tolerant beans was therefore investigated. RESULTS: The MYB60 gene of common bean, with orthology to the Arabidopsis AtMYB60 gene, was found to have conserved regions with MYB60 typical motifs and architecture. Stomata-specific expression of PvMYB60 was further confirmed by q-RT PCR on organs containing stomata, and stomata-enriched leaf fractions. Further, function of PvMYB60 in promoting stomata aperture was confirmed by complementing the defective phenotype of a previously described Arabidopsis myb60-1 mutant. CONCLUSIONS: Our study finally points PvMYB60 as a potential target for obtaining more drought-tolerant common beans in the present context of climate change which would further greatly contribute to food security particularly in drought-prone countries.
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Cambio Climático , Resistencia a la Sequía , Phaseolus , Arabidopsis/genética , Arabidopsis/fisiología , Resistencia a la Sequía/genética , Regulación de la Expresión Génica de las Plantas/genética , Phaseolus/genética , Phaseolus/fisiología , Proteínas de Plantas/genética , Estomas de Plantas/genética , Estomas de Plantas/fisiología , Factores de Transcripción/genéticaRESUMEN
Plants synchronize their growth and development with environmental changes, which is critical for their survival. Among their life cycle transitions, seed germination is key for ensuring the survival and optimal growth of the next generation. However, even under favorable conditions, often germination can be blocked by seed dormancy, a regulatory multilayered checkpoint integrating internal and external signals. Intricate genetic and epigenetic mechanisms underlie seed dormancy establishment, maintenance, and release. In this review, we focus on recent advances that shed light on the complex mechanisms associated with physiological dormancy, prevalent in seed plants, with Arabidopsis thaliana serving as a model. Here, we summarize the role of multiple epigenetic regulators, but with a focus on histone modifications such as acetylation and methylation, that finely tune dormancy responses and influence dormancy-associated gene expression. Understanding these mechanisms can lead to a better understanding of seed biology in general, as well as resulting in the identification of possible targets for breeding climate-resilient plants.
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Arabidopsis , Epigénesis Genética , Histonas , Latencia en las Plantas , Procesamiento Proteico-Postraduccional , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Latencia en las Plantas/genética , Histonas/metabolismo , Histonas/genética , Semillas/crecimiento & desarrollo , Semillas/genética , Semillas/fisiología , Semillas/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , GerminaciónRESUMEN
Shade avoidance syndrome is an important adaptive strategy. Under shade, major transcriptional rearrangements underlie the reallocation of resources to elongate vegetative structures and redefine the plant architecture to compete for photosynthesis. BBX28 is a B-box transcription factor involved in seedling de-etiolation and flowering in Arabidopsis (Arabidopsis thaliana), but its function in shade-avoidance response is completely unknown. Here, we studied the function of BBX28 using two mutant and two transgenic lines of Arabidopsis exposed to white light and simulated shade conditions. We found that BBX28 promotes hypocotyl growth under shade through the phytochrome system by perceiving the reduction of red photons but not the reduction of photosynthetically active radiation or blue photons. We demonstrated that hypocotyl growth under shade is sustained by the protein accumulation of BBX28 in the nuclei in a CONSTITUTIVE PHOTOMORPHOGENESIS1 (COP1)-dependent manner at the end of the photoperiod. BBX28 up-regulates the expression of transcription factor- and auxin-related genes, thereby promoting hypocotyl growth under prolonged shade. Overall, our results suggest the role of BBX28 in COP1 signaling to sustain the shade-avoidance response and extend the well-known participation of other members of BBX transcription factors for fine-tuning plant growth under shade.
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Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Hipocótilo , Luz , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Arabidopsis/fisiología , Arabidopsis/efectos de la radiación , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Hipocótilo/crecimiento & desarrollo , Hipocótilo/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Plantas Modificadas Genéticamente , Mutación/genética , Ácidos Indolacéticos/metabolismo , Fotoperiodo , Transducción de Señal/genéticaRESUMEN
Sulfur (S) is an essential macronutrient for plants and its availability in soils is an important determinant for growth and development. Current regulatory policies aimed at reducing industrial S emissions together with changes in agronomical practices have led to a decline in S contents in soils worldwide. Deficiency of sulfate-the primary form of S accessible to plants in soil-has adverse effects on both crop yield and nutritional quality. Hence, recent research has increasingly focused on unraveling the molecular mechanisms through which plants detect and adapt to a limiting supply of sulfate. A significant part of these studies involves the use of omics technologies and has generated comprehensive catalogs of sulfate deficiency-responsive genes and processes, principally in Arabidopsis together with a few studies centering on crop species such as wheat, rice, or members of the Brassica genus. Although we know that sulfate deficiency elicits an important reprogramming of the transcriptome, the transcriptional regulators orchestrating this response are not yet well understood. In this review, we summarize our current knowledge of gene expression responses to sulfate deficiency and recent efforts towards the identification of the transcription factors that are involved in controlling these responses. We further compare the transcriptional response and putative regulators between Arabidopsis and two important crop species, rice and tomato, to gain insights into common mechanisms of the response to sulfate deficiency.
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Regulación de la Expresión Génica de las Plantas , Redes Reguladoras de Genes , Sulfatos , Sulfatos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Arabidopsis/fisiología , Oryza/genética , Oryza/metabolismo , Oryza/crecimiento & desarrolloRESUMEN
KEY MESSAGE: Lastly, the bZIP gene family encompasses genes that have been reported to play a role in flower development, such as bZIP14 (FD). Notably, bZIP14 is essential for Flowering Locus T (FT) initiation of floral development in Arabidopsis (Abe et al. 2005). Cotton (Gossypium hirsutum L.) is the world's most extensively cultivated fiber crop. However, its reproductive development is poorly characterized at the molecular level. Thus, this study presents a detailed transcriptomic analysis of G. hirsutum at three different reproductive stages. We provide evidence that more than 64,000 genes are active in G. hirsutum during flower development, among which 94.33% have been assigned to functional terms and specific pathways. Gene set enrichment analysis (GSEA) revealed that the biological process categories of floral organ development, pollen exine formation, and stamen development were enriched among the genes expressed during the floral development of G. hirsutum. Furthermore, we identified putative Arabidopsis homologs involved in the G. hirsutum gene regulatory network (GRN) of pollen and flower development, including transcription factors such as WUSCHEL (WUS), INNER NO OUTER (INO), AGAMOUS-LIKE 66 (AGL66), SPOROCYTELESS/NOZZLE (SPL/NZZ), DYSFUNCTIONAL TAPETUM 1 (DYT1), ABORTED MICROSPORES (AMS), and ASH1-RELATED 3 (ASHR3), which are known crucial genes for plant reproductive success. The cotton MADS-box protein-protein interaction pattern resembles the previously described patterns for AGAMOUS (AG), SEEDSTICK (STK), SHATTERPROOF (SHP), and SEPALLATA3 (SEP3) homolog proteins from Arabidopsis. In addition to serving as a resource for comparative flower development studies, this work highlights the changes in gene expression profiles and molecular networks underlying stages that are valuable for cotton breeding improvement.
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Flores , Regulación de la Expresión Génica de las Plantas , Redes Reguladoras de Genes , Gossypium , Gossypium/genética , Gossypium/crecimiento & desarrollo , Gossypium/fisiología , Flores/genética , Flores/crecimiento & desarrollo , Reproducción/genética , Transcriptoma , Perfilación de la Expresión Génica , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/fisiologíaRESUMEN
BACKGROUND AND AIMS: Plants respond in a plastic manner to seasonal changes, often resulting in adaptation to environmental variation. Although much is known about how seasonality regulates developmental transitions within generations, transgenerational effects of non-stressful environmental changes are only beginning to be unveiled. This study aimed to evaluate the effects of ambient temperature changes on the expression of transgenerational plasticity in key developmental traits of Arabidopsis thaliana plants. METHODS: We grew Columbia-0 plants in two contrasting temperature environments (18 and 24 °C) during their whole life cycles, or the combination of those temperatures before and after bolting (18-24 and 24-18 °C) across two generations. We recorded seed germination, flowering time and reproductive biomass production for the second generation, and seed size of the third generation. KEY RESULTS: The environment during the whole life cycle of the first generation of plants, even that experienced before flowering, influenced the germination response and flowering time of the second generation. These effects showed opposing directions in a pattern dependent on the life stage experiencing the cue in the first generation. In contrast, the production of reproductive biomass depended on the immediate environment of the progeny generation. Finally, the seed area of the third generation was influenced positively by correlated environments across generations. CONCLUSIONS: Our results suggest that non-stressful environmental changes affect the expression of key developmental traits across generations, although those changes can have contrasting effects depending on the parental and grandparental life stage that perceives the cue. Thus, transgenerational effects in response to non-stressful cues might influence the expression of life-history traits and potential adaptation of future generations.
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Arabidopsis , Animales , Arabidopsis/fisiología , Temperatura , Germinación/fisiología , Estadios del Ciclo de Vida , Semillas/fisiología , Adaptación FisiológicaRESUMEN
Adaptation to different soil conditions is a well-regulated process vital for plant life. AtHB23 is a homeodomain-leucine zipper I transcription factor (TF) that was previously revealed as crucial for plant survival under salinity conditions. We wondered whether this TF has partners to perform this essential function. Therefore, TF cDNA library screening, yeast two-hybrid, bimolecular fluorescence complementation, and coimmunoprecipitation assays were complemented with expression analyses and phenotypic characterization of silenced, mutant, overexpression, and crossed plants in normal and salinity conditions. We revealed that AtHB23, AtPHL1, and AtMYB68 interact with each other, modulating root development and the salinity response. The encoding genes are coexpressed in specific root tissues and at specific developmental stages. In normal conditions, amiR68 silenced plants have fewer initiated roots, the opposite phenotype to that shown by amiR23 plants. AtMYB68 and AtPHL1 play opposite roles in lateral root elongation. Under salinity conditions, AtHB23 plays a crucial positive role in cooperating with AtMYB68, whereas AtPHL1 acts oppositely by obstructing the function of the former, impacting the plant's survival ability. Such interplay supports the complex interaction between these TF in primary and lateral roots. The root adaptation capability is associated with the amyloplast state. We identified new molecular players that through a complex relationship determine Arabidopsis root architecture and survival in salinity conditions.
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Proteínas de Arabidopsis , Arabidopsis , Raíces de Plantas , Tolerancia a la Sal , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Tolerancia a la Sal/genéticaRESUMEN
Plant natriuretic peptides (PNPs) are hormone peptides that participate in the regulation of ions and water homeostasis in plants. Xanthomonas citri subsp. citri (Xcc) the causal agent of citrus canker disease also possesses a PNP-like peptide (XacPNP). This peptide, similarly to AtPNP-A, the most studied PNP from Arabidopsis thaliana, causes stomatal aperture and enhances photosynthetic efficiency in plant leaves. Thus, the function that has been attributed to XacPNP is to contribute to maintain photosynthetic efficiency and water homeostasis in plant tissue during the infection process, to create favorable conditions for biotrophic pathogens survival. A PNP receptor (AtPNP-R1) for AtPNP-A has been identified and the AtPNP-A activity in regulation of water homeostasis has been observed to depend on the presence of AtPNP-R1. Here, we demonstrated that both AtPNP-A and XacPNP require the presence of AtPNP-R1 to induce plant stomatal aperture. Also, less necrotic tissue was found in infections with pathogens expressing XacPNP and this was dependent on the presence of AtPNP-R1, suggesting that XacPNP interacts with this receptor to exert its function. Finally, we confirmed that AtPNP-A and XacPNP interact with AtPNP-R1 in planta, which support the idea that XacPNP triggers similar plant responses to its plant counterpart.
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Arabidopsis , Citrus , Xanthomonas , Arabidopsis/fisiología , Xanthomonas/fisiología , Plantas , Péptidos Natriuréticos/fisiología , Agua , Enfermedades de las PlantasRESUMEN
Understanding how the environment regulates seed-bank dormancy changes is essential for forecasting seedling emergence in actual and future climatic scenarios, and to interpret studies of dormancy mechanisms at physiological and molecular levels. Here, we used a population threshold modelling approach to analyse dormancy changes through variations in the thermal range permissive for germination in buried seeds of Arabidopsis thaliana Cvi, a winter annual ecotype. Results showed that changes in dormancy level were mainly associated with variations in the higher limit of the thermal range permissive for germination. Changes in this limit were positively related to soil temperature during dormancy release and induction, and could be predicted using thermal time. From this, we developed a temperature-driven simulation to predict the fraction of the seed bank able to germinate in a realistic global warming scenario that approximated seedling emergence timing. Simulations predicted, in accordance with seedling emergence observed in the field, an increase in the fraction of the seed bank able to emerge as a result of global warming. In addition, our results suggest that buried seeds perceive changes in the variability of the mean daily soil temperature as the signal to change between dormancy release and induction according to the seasons.
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Arabidopsis , Arabidopsis/fisiología , Germinación/fisiología , Calentamiento Global , Latencia en las Plantas/fisiología , Estaciones del Año , Plantones/fisiología , Semillas/fisiología , Suelo , TemperaturaRESUMEN
Nitrate is a nutrient and a potent signal that impacts global gene expression in plants. However, the regulatory factors controlling temporal and cell type-specific nitrate responses remain largely unknown. We assayed nitrate-responsive transcriptome changes in five major root cell types of the Arabidopsis thaliana root as a function of time. We found that gene-expression response to nitrate is dynamic and highly localized and predicted cell type-specific transcription factor (TF)-target interactions. Among cell types, the endodermis stands out as having the largest and most connected nitrate-regulatory gene network. ABF2 and ABF3 are major hubs for transcriptional responses in the endodermis cell layer. We experimentally validated TF-target interactions for ABF2 and ABF3 by chromatin immunoprecipitation followed by sequencing and a cell-based system to detect TF regulation genome-wide. Validated targets of ABF2 and ABF3 account for more than 50% of the nitrate-responsive transcriptome in the endodermis. Moreover, ABF2 and ABF3 are involved in nitrate-induced lateral root growth. Our approach offers an unprecedented spatiotemporal resolution of the root response to nitrate and identifies important components of cell-specific gene regulatory networks.
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Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Proteínas de Unión al ADN/genética , Regulación de la Expresión Génica de las Plantas , Nitratos/metabolismo , Fenómenos Fisiológicos de las Plantas , Factores de Transcripción/genética , Arabidopsis/fisiología , Proteínas de Arabidopsis/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Biología Computacional/métodos , Proteínas de Unión al ADN/metabolismo , Perfilación de la Expresión Génica , Ontología de Genes , Redes Reguladoras de Genes , Modelos Biológicos , Especificidad de Órganos/genética , Raíces de Plantas/fisiología , Factores de Transcripción/metabolismo , TranscriptomaRESUMEN
Arabidopsis (Arabidopsis thaliana) primary and lateral roots (LRs) are well suited for 3D and 4D microscopy, and their development provides an ideal system for studying morphogenesis and cell proliferation dynamics. With fast-advancing microscopy techniques used for live-imaging, whole tissue data are increasingly available, yet present the great challenge of analyzing complex interactions within cell populations. We developed a plugin "Live Plant Cell Tracking" (LiPlaCeT) coupled to the publicly available ImageJ image analysis program and generated a pipeline that allows, with the aid of LiPlaCeT, 4D cell tracking and lineage analysis of populations of dividing and growing cells. The LiPlaCeT plugin contains ad hoc ergonomic curating tools, making it very simple to use for manual cell tracking, especially when the signal-to-noise ratio of images is low or variable in time or 3D space and when automated methods may fail. Performing time-lapse experiments and using cell-tracking data extracted with the assistance of LiPlaCeT, we accomplished deep analyses of cell proliferation and clonal relations in the whole developing LR primordia and constructed genealogical trees. We also used cell-tracking data for endodermis cells of the root apical meristem (RAM) and performed automated analyses of cell population dynamics using ParaView software (also publicly available). Using the RAM as an example, we also showed how LiPlaCeT can be used to generate information at the whole-tissue level regarding cell length, cell position, cell growth rate, cell displacement rate, and proliferation activity. The pipeline will be useful in live-imaging studies of roots and other plant organs to understand complex interactions within proliferating and growing cell populations. The plugin includes a step-by-step user manual and a dataset example that are available at https://www.ibt.unam.mx/documentos/diversos/LiPlaCeT.zip.
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Arabidopsis/fisiología , Proliferación Celular , Rastreo Celular/instrumentación , Células Vegetales/fisiología , Desarrollo de la Planta , Arabidopsis/crecimiento & desarrolloRESUMEN
The lipid matrix in cell membranes is a dynamic, bidimensional array of amphipathic molecules exhibiting mesomorphism, which contributes to the membrane fluidity changes in response to temperature fluctuation. As sessile organisms, plants must rapidly and accurately respond to environmental thermal variations. However, mechanisms underlying temperature perception in plants are poorly understood. We studied the thermal plasticity of membrane fluidity using three fluorescent probes across a temperature range of -5 to 41 °C in isolated microsomal fraction (MF), vacuolar membrane (VM), and plasma membrane (PM) vesicles from Arabidopsis plants. Results showed that PM were highly fluid and exhibited more phase transitions and hysteresis, while VM and MF lacked such attributes. These findings suggest that PM is an important cell hub with the capacity to rapidly undergo fluidity modifications in response to small changes of temperatures in ranges spanning those experienced in natural habitats. PM fluidity behaves as an ideal temperature detector: it is always present, covers the whole cell, responds quickly and with sensitivity to temperature variations, functions with a cell free-energy cost, and it is physically connected with potential thermal signal transducers to elicit a cell response. It is an optimal alternative for temperature detection selected for the plant kingdom.
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Arabidopsis/fisiología , Membrana Celular/fisiología , Fluidez de la Membrana/fisiología , Arabidopsis/ultraestructura , Membrana Celular/ultraestructura , Colorantes Fluorescentes/metabolismo , Temperatura , Vacuolas/metabolismo , Vacuolas/ultraestructuraRESUMEN
The most studied DNA methylation pathway in plants is the RNA Directed DNA Methylation (RdDM), a conserved mechanism that involves the role of noncoding RNAs to control the expansion of the noncoding genome. Genome-wide DNA methylation levels have been reported to correlate with genome size. However, little is known about the catalog of noncoding RNAs and the impact on DNA methylation in small plant genomes with reduced noncoding regions. Because of the small length of intergenic regions in the compact genome of the carnivorous plant Utricularia gibba, we investigated its repertoire of noncoding RNA and DNA methylation landscape. Here, we report that, compared to other angiosperms, U. gibba has an unusual distribution of small RNAs and reduced global DNA methylation levels. DNA methylation was determined using a novel strategy based on long-read DNA sequencing with the Pacific Bioscience platform and confirmed by whole-genome bisulfite sequencing. Moreover, some key genes involved in the RdDM pathway may not represented by compensatory paralogs or comprise truncated proteins, for example, U. gibba DICER-LIKE 3 (DCL3), encoding a DICER endonuclease that produces 24-nt small-interfering RNAs, has lost key domains required for complete function. Our results unveil that a truncated DCL3 correlates with a decreased proportion of 24-nt small-interfering RNAs, low DNA methylation levels, and developmental abnormalities during female gametogenesis in U. gibba. Alterations in female gametogenesis are reminiscent of RdDM mutant phenotypes in Arabidopsis thaliana. It would be interesting to further study the biological implications of the DCL3 truncation in U. gibba, as it could represent an initial step in the evolution of RdDM pathway in compact genomes.
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Metilación de ADN , Endonucleasas/genética , Endonucleasas/metabolismo , Gametogénesis , Lamiales/fisiología , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Mutación , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , ARN de Planta , ARN no Traducido/metabolismo , Ribonucleasa III/genética , Ribonucleasa III/metabolismoRESUMEN
Cold and freezing stresses severely affect plant growth, development, and survival rate. Some plant species have evolved a process known as cold acclimation, in which plants exposed to temperatures above 0 °C trigger biochemical and physiological changes to survive freezing. During this response, several signaling events are mediated by transducers, such as mitogen activated protein kinase (MAPK) cascades. Plasma membrane H+-ATPase is a key enzyme for the plant cell life under regular and stress conditions. Using wild type and mpk3 and mpk6 knock out mutants in Arabidopsis thaliana, we explored the transcriptional, translational, and 14-3-3 protein regulation of the plasma membrane H+-ATPase activity under the acclimation process. The kinetic analysis revealed a differential profiling of the H+-ATPase activity depending on the presence or absence of MPK3 or MPK6 under non-acclimated or acclimated conditions. Negative regulation of the plasma membrane H+-ATPase activity was found to be exerted by MPK3 in non-acclimated conditions and by MPK6 in acclimated conditions, describing a novel form of regulation of this master ATPase. The MPK6 regulation involved changes in plasma membrane fluidity. Moreover, our results indicated that MPK6 is a critical regulator in the process of cold acclimation that leads to freezing tolerance and further survival.
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Aclimatación/fisiología , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Arabidopsis/fisiología , Membrana Celular/enzimología , Frío , Proteínas Quinasas Activadas por Mitógenos/metabolismo , ATPasas de Translocación de Protón/metabolismo , Congelación , Cinética , Fluidez de la Membrana , Biosíntesis de Proteínas , Transcripción GenéticaRESUMEN
Mitochondrial uncoupling proteins (UCPs) are mitochondrial inner membrane proteins that dissipate the proton electrochemical gradient generated by the respiratory chain complexes. In plants, these proteins are crucial for maintaining mitochondrial reactive oxygen species (ROS) homeostasis. In this study, single T-DNA insertion mutants for two (AtUCP1 and AtUCP2) out of the three UCP genes present in Arabidopsis thaliana were employed to elucidate their potential roles in planta. Our data revealed a significant increase in the Adenosine triphosphate (ATP)/Adenosine diphosphate (ADP) ratios of both mutants, indicating clear alterations in energy metabolism, and a reduced respiratory rate in atucp2. Phenotypic characterization revealed that atucp1 and atucp2 plants displayed reduced primary root growth under normal and stressed conditions. Moreover, a reduced fertility phenotype was observed in both mutants, which exhibited an increased number of sterile siliques and a lower seed yield compared with wild-type plants. Reciprocal crosses demonstrated that both male fertility and female fertility were compromised in atucp1, while such effect was exclusively observed in the male counterpart in atucp2. Most strikingly, a pronounced accumulation of hydrogen peroxide in the reproductive organs was observed in all mutant lines, indicating a disturbance in ROS homeostasis of mutant flowers. Accordingly, the atucp1 and atucp2 mutants exhibited higher levels of ROS in pollen grains. Further, alternative oxidase 1a was highly induced in mutant flowers, while the expression profiles of transcription factors implicated in gene regulation during female and male reproductive organ/tissue development were perturbed. Overall, these data support the important role for AtUCP1 and AtUCP2 in flower oxidative homeostasis and overall plant fertility.
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Proteínas de Arabidopsis/genética , Arabidopsis/fisiología , Regulación de la Expresión Génica de las Plantas , Proteínas Desacopladoras Mitocondriales/genética , Proteína Desacopladora 1/genética , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/metabolismo , Proteínas Desacopladoras Mitocondriales/metabolismo , Proteína Desacopladora 1/metabolismoRESUMEN
Inflorescence movements in response to natural gradients of sunlight are frequently observed in the plant kingdom and are suggested to contribute to reproductive success. Although the physiological and molecular bases of light-mediated tropisms in vegetative organs have been thoroughly investigated, the mechanisms that control inflorescence orientation in response to light gradients under natural conditions are not well understood. In this work, we have used a combination of laboratory and field experiments to investigate light-mediated re-orientation of Arabidopsis thaliana inflorescences. We show that inflorescence phototropism is promoted by photons in the UV and blue spectral range (≤500 nm) and depends on multiple photoreceptor families. Experiments under controlled conditions show that UVR8 is the main photoreceptor mediating the phototropic response to narrowband UV-B radiation, and phototropins and cryptochromes control the response to narrowband blue light. Interestingly, whereas phototropins mediate bending in response to low irradiances of blue, cryptochromes are the principal photoreceptors acting at high irradiances. Moreover, phototropins negatively regulate the action of cryptochromes at high irradiances of blue light. Experiments under natural field conditions demonstrate that cryptochromes are the principal photoreceptors acting in the promotion of the heliotropic response of inflorescences under full sunlight.
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Proteínas de Arabidopsis/genética , Arabidopsis/fisiología , Proteínas Cromosómicas no Histona/genética , Citocromos/genética , Fotorreceptores de Plantas/genética , Fototropismo/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Citocromos/metabolismo , Fotorreceptores de Plantas/metabolismoRESUMEN
Flowering is one of the most critical developmental transitions in plants' life. The irreversible change from the vegetative to the reproductive stage is strictly controlled to ensure the progeny's success. In Arabidopsis thaliana, seven flowering genetic pathways have been described under specific growth conditions. However, the evidence condensed here suggest that these pathways are tightly interconnected in a complex multilevel regulatory network. In this review, we pursue an integrative approach emphasizing the molecular interactions among the flowering regulatory network components. We also consider that the same regulatory network prevents or induces flowering phase change in response to internal cues modulated by environmental signals. In this sense, we describe how during the vegetative phase of development it is essential to prevent the expression of flowering promoting genes until they are required. Then, we mention flowering regulation under suboptimal growing temperatures, such as those in autumn and winter. We next expose the requirement of endogenous signals in flowering, and finally, the acceleration of this transition by long-day photoperiod and temperature rise signals allowing A. thaliana to bloom in spring and summer seasons. With this approach, we aim to provide an initial systemic view to help the reader integrate this complex developmental process.
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Arabidopsis/fisiología , Flores/fisiología , Regulación de la Expresión Génica de las Plantas , Transducción de Señal , Biomarcadores , Redes Reguladoras de Genes , Fotoperiodo , Desarrollo de la Planta/genética , Estaciones del Año , TemperaturaRESUMEN
Plant long noncoding RNAs (lncRNAs) are key chromatin dynamics regulators, directing the transcriptional programs driving a wide variety of developmental outputs. Recently, we uncovered how the lncRNA AUXIN REGULATED PROMOTER LOOP (APOLO) directly recognizes the locus encoding the root hair (RH) master regulator ROOT HAIR DEFECTIVE 6 (RHD6) modulating its transcriptional activation and leading to low temperature-induced RH elongation. We further demonstrated that APOLO interacts with the transcription factor WRKY42 in a novel ribonucleoprotein complex shaping RHD6 epigenetic environment and integrating signals governing RH growth and development. In this work, we expand this model showing that APOLO is able to bind and positively control the expression of several cell wall EXTENSIN (EXT) encoding genes, including EXT3, a key regulator for RH growth. Interestingly, EXT3 emerged as a novel common target of APOLO and WRKY42. Furthermore, we showed that the ROS homeostasis-related gene NADPH OXIDASE C (NOXC) is deregulated upon APOLO overexpression, likely through the RHD6-RSL4 pathway, and that NOXC is required for low temperature-dependent enhancement of RH growth. Collectively, our results uncover an intricate regulatory network involving the APOLO/WRKY42 hub in the control of master and effector genes during RH development.