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DELLA proteins are negative regulators of the gibberellin response pathway in angiosperms, acting as central hubs that interact with hundreds of transcription factors (TFs) and regulators to modulate their activities. While the mechanism of TF sequestration by DELLAs to prevent DNA binding to downstream targets has been extensively documented, the mechanism that allows them to act as coactivators remains to be understood. Here, we demonstrate that DELLAs directly recruit the Mediator complex to specific loci in Arabidopsis, facilitating transcription. This recruitment involves DELLA amino-terminal domain and the conserved MED15 KIX domain. Accordingly, partial loss of MED15 function mainly disrupted processes known to rely on DELLA coactivation capacity, including cytokinin-dependent regulation of meristem function and skotomorphogenic response, gibberellin metabolism feedback, and flavonol production. We have also found that the single DELLA protein in the liverwort Marchantia polymorpha is capable of recruiting MpMED15 subunits, contributing to transcriptional coactivation. The conservation of Mediator-dependent transcriptional coactivation by DELLA between Arabidopsis and Marchantia implies that this mechanism is intrinsic to the emergence of DELLA in the last common ancestor of land plants.

Most plant growth and development processes are regulated in one way or another by auxin. The best-studied mechanism by which auxin exerts its regulatory effects is through the nuclear auxin pathway (NAP). In this pathway, Auxin Response Factors (ARFs) are the transcription factors that ultimately determine which genes become auxin regulated by binding to specific DNA sequences. ARFs have primarily been studied in Arabidopsis thaliana, but recent studies in other species have revealed family-wide DNA binding specificities for different ARFs and the minimal functional system of the NAP system, consisting of a duo of competing ARFs of the A and B classes. In this review, we provide an overview of key aspects of ARF DNA binding such as auxin response elements (TGTCNN) and tandem repeat motifs, and consider how structural biology and in vitro studies help us understand ARF DNA preferences. We also highlight some recent aspects related to the regulation of ARF levels inside a cell, which may alter the DNA binding profile of ARFs in different tissues. We finally emphasize the need to study minimal NAP systems to understand fundamental aspects of ARF function, the need to characterize algal ARFs to understand how ARFs evolved, how cutting-edge techniques can increase our understanding of ARFs, and which remaining questions can only be answered by structural biology.

DELLA proteins are negative regulators of the gibberellin response pathway in angiosperms, acting as central hubs that interact with hundreds of transcription factors and regulators to modulate their activities. While the mechanism of transcription factor sequestration by DELLAs to prevent DNA binding to downstream targets has been extensively documented, the mechanism that allows them to act as co-activators remains to be understood. Here, we demonstrate that DELLAs directly recruit the Mediator complex to specific loci in Arabidopsis, facilitating transcription. This recruitment involves DELLA amino-terminal domain and the conserved MED15 KIX domain. Accordingly, partial loss of MED15 function mainly disrupted processes known to rely on DELLA co-activation capacity; including cytokinin-dependent regulation of meristem function and skotomorphogenic response, gibberellin metabolism feedback, and flavonol production. We have also found that the single DELLA protein in the liverwort Marchantia polymorpha is capable of recruiting MpMED15 subunits, contributing to transcriptional co-activation. The conservation of Mediator-dependent transcriptional co-activation by DELLA between Arabidopsis and Marchantia implies that this mechanism is intrinsic to the emergence of DELLA in the last common ancestor of land plants.

Zygnematophycean algae represent the streptophyte group identified as the closest sister clade to land plants. Their phylogenetic position and growing genomic resources make these freshwater algae attractive models for evolutionary studies in the context of plant terrestrialization. However, available genetic transformation protocols are limited and exclusively DNA-based. To expand the zygnematophycean toolkit, we developed a DNA-free method for protein delivery into intact cells using electroporation. We use confocal microscopy coupled with fluorescence lifetime imaging to assess the delivery of mNeonGreen into algal cells. We optimized the method to obtain high efficiency of delivery and cell recovery after electroporation in two strains of Penium margaritaceum and show that the experimental setup can also be used to deliver proteins in other zygnematophycean species such as Closterium peracerosum-strigosum-littorale complex and Mesotaenium endlicherianum. We discuss the possible applications of this proof-of-concept method.

Over millions of years, eukaryotes evolved from unicellular to multicellular organisms with increasingly complex genomes and sophisticated gene expression networks. Consequently, chromatin regulators evolved to support this increased complexity. The ATP-dependent chromatin remodelers of the SWI/SNF family are multiprotein complexes that modulate nucleosome positioning and appear under different configurations, which perform distinct functions. While the composition, architecture, and activity of these subclasses are well understood in a limited number of fungal and animal model organisms, the lack of comprehensive information in other eukaryotic organisms precludes the identification of a reliable evolutionary model of SWI/SNF complexes. Here, we performed a systematic analysis using 36 species from animal, fungal, and plant lineages to assess the conservation of known SWI/SNF subunits across eukaryotes. We identified evolutionary relationships that allowed us to propose the composition of a hypothetical ancestral SWI/SNF complex in the last eukaryotic common ancestor. This last common ancestor appears to have undergone several rounds of lineage-specific subunit gains and losses, shaping the current conformation of the known subclasses in animals and fungi. In addition, our results unravel a plant SWI/SNF complex, reminiscent of the animal BAF subclass, which incorporates a set of plant-specific subunits of still unknown function.

[ES] Las proteínas DELLA son reguladores de procesos del desarrollo y el crecimiento de las plantas, involucradas en la vía de señalización de las giberelinas (GAs). Las proteínas DELLA no pueden unirse al DNA por sí solas y su mecanismo de acción es la interacción mediante su dominio GRAS con factores de transcripción (FT) y con reguladores de la transcripción (RT), a través de los cuales modula la expresión de sus genes diana. Los modos de acción de las proteínas DELLA son el secuestro de FTs y RTs, impidiendo su actividad normal, y la coactivación, promoviéndola. Al dominio N-terminal de las DELLA solamente se le ha atribuido la función del control de la estabilidad dependiente de GAs, a través de la interacción con el receptor de GAs codificado por GID1. Sin embargo, aunque sólo hay genes GID1 en plantas vasculares, las DELLA de las plantas no vasculares (briófitas) presentan una sorprendente conservación de su domino N-terminal, que se ha atribuido a su papel adicional como activador de la transcripción por contener motivos denominados ¿dominios de transactivación de nueve aminoácidos¿ (9aaTAD). Estos dominios frecuentemente interaccionan con dominios de interacción inducibles por quinasas (KIX), presentes en complejos coactivadores de la transcripción. Trabajo previo del laboratorio indica que la capacidad transactivadora del dominio N-terminal de las DELLA de Arabidopsis depende de su interacción con MED15, una subunidad de la cola del complejo Mediator que facilita la actividad de la RNA Polimerasa II. En este trabajo nos planteamos la pregunta de si éste es el mecanismo que utilizan también las DELLA de briófitas para ejercer como coactivadoras. Para resolverlo, decidimos trabajar con la briófita Marchantia polymorpha, cuyo linaje se separó de las plantas vasculares en un punto muy temprano tras la colonización de la superficie terrestre. Mediante análisis filogenéticos hemos identificado una secuencia MpMED15 con su dominio KIX conservado, a través del cua, [EN] DELLA proteins are regulators of plant growth and development processes, involved in the gibberellin signalling pathway (GAs). DELLA proteins can¿t bind to DNA by themselves. Their mechanism of action is the interaction through their GRAS domain with transcription factors (FT) and transcription regulators (RT), through which they modulate the expression of their target genes. The modes of action of DELLA proteins are the sequestration of FTs and RTs, preventing their normal activity, and coactivation, promoting it. Only the GA-dependent stability control function has been attributed to the N-terminal domain of DELLA, through interaction with the GAs receptor encoded by GID1. However, although there are only GID1 genes in vascular plants, the DELLAs of non-vascular plants (bryophytes) show a surprising conservation of their N-terminal domain, which has been attributed to their additional role as an activator of transcription because they contain motifs called "Nine amino acid transactivation domains" (9aaTAD). These domains frequently interact with kinase-inducible interaction domains (KIX), present in transcriptional coactivator complexes. Previous laboratory work indicates that the transactivating capacity of the N-terminal domain of Arabidopsis DELLAs depends on its interaction with MED15, a subunit of the tail of the Mediator complex that facilitates RNA polymerase II activity. In this work we are wondering whether this is the mechanism that the DELLA of bryophytes also use to act as co-activators. To solve this, we decided to work with the bryophyte Marchantia polymorpha, whose lineage separated from vascular plants at a very early point after colonization of the earth's surface. Through phylogenetic analysis we have identified an MpMED15 sequence with its conserved KIX domain, by which it interacts with the N-terminal domain of MpDELLA, according to yeast two hybrid (Y2H) and Bimolecular Fluorescence Complementation (BiFC) assays. We have also verified tha

[ES] Las plantas necesitan acomodar su crecimiento a las condiciones ambientales. Con el objetivo de ajustar su desarrollo a las señales externas, usan una serie de mecanismos moleculares. Uno de estos son las rutas de señalización hormonal, que participan en integrar la información externa con programas de desarrollo propios. Una de las hormonas más relevantes en la biología vegetal son las giberelinas (GAs). La señalización por GAs se inicia con la percepción de la hormona a través del receptor GID1, y continúa por la degradación de las reguladoras transcripcionales DELLA. Sin embargo, solo las plantas vasculares tienen un sistema de percepción de GAs completo. Entender la relevancia de la señalización por GAs requiere estudiar cómo se ensambló la ruta y qué funciones atribuidas a las GAs estaban ya codificadas en las proteínas DELLA ancestrales. Aquí mostramos mediante análisis filogenéticos y bioquímicos que las proteínas DELLA emergieron inequívocamente en un ancestro común de las plantas terrestres, y que el reclutamiento de las DELLAs al módulo de percepción de GAs depende de la presencia de un dominio de transactivación conservado que fue co-optado por el receptor GID1 ancestral para actuar como un degrón dependiente de GAs. Este dominio de transactivación parece regular la co-activación transcripcional de genes concretos por las DELLAs en todas las plantas terrestres mediante el reclutamiento de complejos Mediator a través de su subunidad MED15. Por último, nos hemos centrado en entender las funciones de las proteínas DELLA en briófitas, un clado sin señalización por GAs. Hemos descubierto el rol de la DELLA de Marchantia polymorpha como coordinadora entre las respuestas de crecimiento y estrés, sugiriendo que dicha función estaba ya codificada en proteínas DELLA del ancestro común de plantas terrestres y se ha mantenido durante más de 450 millones de años., [CA] Les plantes necessiten acomodar el seu creixement a les condicions ambientals. Amb l'objectiu d'ajustar el seu desenvolupament als senyals externs, usen una sèrie de mecanismes moleculars. Un d'aquests són les rutes de senyalització hormonal, que participen en integrar la informació externa amb programes de desenvolupament propis. Una de les hormones més rellevants en la biologia vegetal són les giberel·lines (GAs). La senyalització per GAs s'inicia amb la percepció de l'hormona a través del receptor GID1, i continua per la degradació de les reguladores transcripcionals DELLA. No obstant això, només les plantes vasculars tenen un sistema complet de percepció de GAs. Entendre la rellevància de la senyalització per GAs requereix estudiar com es va assemblar la ruta i quines funcions atribuïdes a les GAs estaven ja codificades en les proteïnes DELLA ancestrals. Ací mostrem mitjançant anàlisis filogenètiques i bioquímiques que les proteïnes DELLA van emergir inequívocament en un ancestre comú de les plantes terrestres, i que el reclutament de les DELLAs al mòdul de percepció de GAs depén de la presència d'un domini de transactivació conservat que va ser co-optat pel receptor GID1 ancestral per a actuar com un degró dependent de GAs. Aquest domini de transactivació sembla regular la co-activació transcripcional de gens concrets per les DELLAs en totes les plantes terrestres mitjançant el reclutament de complexos Mediator a través de la seua subunitat MED15. Finalment, ens hem centrat en entendre les funcions de les proteïnes DELLA en briòfites, un clade sense senyalització per GAs. Hem descobert el rol de la DELLA de Marchantia polymorpha com a coordinadora entre les respostes de creixement i estrés, suggerint que aquesta funció estava ja codificada en proteïnes DELLA de l'ancestre comú de plantes terrestres i s'ha mantingut durant més de 450 milions d'anys., [EN] Plants need to accommodate their growth habits to environmental conditions. For this aim, several mechanisms are used to adjust developmental responses to exogenous signals. Among them, hormonal signalling pathways participate by integrating external information with endogenous programs. One of the most relevant hormones in plant biology are gibberellins (GAs). GA signalling involves perception of the hormone by the GA receptor GID1 and subsequent degradation of the DELLA transcriptional regulators. However, only vascular plants possess a full GA perception system. Understanding the relevance of GA signalling requires elucidating how this pathway was assembled and which of the functions attributed to GAs were encoded in the ancestral DELLA proteins. Here we show by phylogenetic and biochemical analyses that DELLA proteins emerged unequivocally in a land plant common ancestor and that their recruitment into the GA-perception module relies in the presence of a conserved transactivation domain co-opted by an ancestral GID1 receptor to act as a GA-dependent degron. Moreover, this transactivation domain seems to regulate DELLA-dependent transcriptional co-activation of selected target genes by recruitment of Mediator complexes through the MED15 subunit in all land plants. Finally, we have focused on understanding the functions of DELLA proteins in bryophytes, a clade with no GA signalling. We have uncovered the role of Marchantia polymorpha DELLA protein as a coordinator between growth and stress responses, suggesting that this function was already present in the DELLA protein of a land plant common ancestor and has been maintained for over 450 millions of years.

Plant survival depends on the optimal use of resources under variable environmental conditions. Among the mechanisms that mediate the balance between growth, differentiation and stress responses, the regulation of transcriptional activity by DELLA proteins stands out. In angiosperms, DELLA accumulation promotes defense against biotic and abiotic stress and represses cell division and expansion, while loss of DELLA function is associated with increased plant size and sensitivity towards stress1. Given that DELLA protein stability is dependent on gibberellin (GA) levels2, and GA metabolism is influenced by the environment3, this pathway is proposed to relay environmental information to the transcriptional programs that regulate growth and stress responses in angiosperms4,5. However, DELLA genes are also found in bryophytes, whereas canonical GA receptors appeared only in vascular plants6–10. Thus, it is not clear whether these regulatory functions of DELLA predated or emerged with typical GA signaling. Here we show that, as in vascular plants, the only DELLA in the liverwort Marchantia polymorpha also participates in the regulation of growth and key developmental processes, and promotes the tolerance towards oxidative stress. Moreover, part of these effects is likely caused by the conserved physical interaction with the MpPIF transcription factor. Therefore, we suggest that the role in the coordination of growth and stress responses was already encoded in DELLA from the common ancestor of land plants, and the importance of this function is justified by its conservation over the past 450 M years.

Plant survival depends on the optimal use of resources under variable environmental conditions. Among the mechanisms that mediate the balance between growth, differentiation, and stress responses, the regulation of transcriptional activity by DELLA proteins stands out. In angiosperms, DELLA accumulation promotes defense against biotic and abiotic stress and represses cell division and expansion, while the loss of DELLA function is associated with increased plant size and sensitivity toward stress.1 Given that DELLA protein stability is dependent on gibberellin (GA) levels2 and GA metabolism is influenced by the environment,3 this pathway is proposed to relay environmental information to the transcriptional programs that regulate growth and stress responses in angiosperms.4,5 However, DELLA genes are also found in bryophytes, whereas canonical GA receptors have been identified only in vascular plants.6, 7, 8, 9, 10 Thus, it is not clear whether these regulatory functions of DELLA predated or emerged with typical GA signaling. Here, we show that, as in vascular plants, the only DELLA in the liverwort Marchantia polymorpha also participates in the regulation of growth and key developmental processes and promotes oxidative stress tolerance. Moreover, part of these effects is likely caused by the conserved physical interaction with the MpPIF transcription factor. Therefore, we suggest that the role in the coordination of growth and stress responses was already encoded in the DELLA protein of the common ancestor of land plants, and the importance of this function is underscored by its conservation over the past 450 million years.

Hornworts comprise a bryophyte lineage that diverged from other extant land plants >400 million years ago and bears unique biological features, including a distinct sporophyte architecture, cyanobacterial symbiosis and a pyrenoid-based carbon-concentrating mechanism (CCM). Here, we provide three high-quality genomes of Anthoceros hornworts. Phylogenomic analyses place hornworts as a sister clade to liverworts plus mosses with high support. The Anthoceros genomes lack repeat-dense centromeres as well as whole-genome duplication, and contain a limited transcription factor repertoire. Several genes involved in angiosperm meristem and stomatal function are conserved in Anthoceros and upregulated during sporophyte development, suggesting possible homologies at the genetic level. We identified candidate genes involved in cyanobacterial symbiosis and found that LCIB, a Chlamydomonas CCM gene, is present in hornworts but absent in other plant lineages, implying a possible conserved role in CCM function. We anticipate that these hornwort genomes will serve as essential references for future hornwort research and comparative studies across land plants.

Hornworts comprise a bryophyte lineage that diverged from other extant land plants >400 million years ago and bears unique biological features, including a distinct sporophyte architecture, cyanobacterial symbiosis and a pyrenoid-based carbon-concentrating mechanism (CCM). Here, we provide three high-quality genomes of Anthoceros hornworts. Phylogenomic analyses place hornworts as a sister clade to liverworts plus mosses with high support. The Anthoceros genomes lack repeat-dense centromeres as well as whole-genome duplication, and contain a limited transcription factor repertoire. Several genes involved in angiosperm meristem and stomatal function are conserved in Anthoceros and upregulated during sporophyte development, suggesting possible homologies at the genetic level. We identified candidate genes involved in cyanobacterial symbiosis and found that LCIB, a Chlamydomonas CCM gene, is present in hornworts but absent in other plant lineages, implying a possible conserved role in CCM function. We anticipate that these hornwort genomes will serve as essential references for future hornwort research and comparative studies across land plants.

[EN] In plants, the only confirmed function for thermospermine is regulating xylem cells maturation. However, genes putatively encoding thermospermine synthases have been identified in the genomes of both vascular and non-vascular plants. Here, we verify the activity of the thermospermine synthase genes and the presence of thermospermine in vascular and non-vascular land plants as well as in the aquatic plant Chlamydomonas reinhardtii. In addition, we provide information about differential content of thermospermine in diverse organs at different developmental stages in some vascular species that suggest that, although the major role of thermospermine in vascular plants is likely to be xylem development, other potential roles in development and/or responses to stress conditions could be associated to such polyamine. In summary, our results in vascular and non-vascular species indicate that the capacity to synthesize thermospermine is conserved throughout the entire plant kingdom.

In plants, the only confirmed function for thermospermine is regulating xylem cells maturation. However, genes putatively encoding thermospermine synthases have been identified in the genomes of both vascular and non-vascular plants. Here, we verify the activity of the thermospermine synthase genes and the presence of thermospermine in vascular and non-vascular land plants as well as in the aquatic plant Chlamydomonas reinhardtii. In addition, we provide information about differential content of thermospermine in diverse organs at different developmental stages in some vascular species that suggest that, although the major role of thermospermine in vascular plants is likely to be xylem development, other potential roles in development and/or responses to stress conditions could be associated to such polyamine. In summary, our results in vascular and non-vascular species indicate that the capacity to synthesize thermospermine is conserved throughout the entire plant kingdom.

[EN] DELLA proteins are plant specific transcriptional regulators known to interact through their C-terminal GRAS domain with over 150 transcription factors in Arabidopsis thaliana. Besides, DELLAs from vascular plants can interact through the N-terminal domain with the gibberellin receptor encoded by GID1, through which gibberellins promote DELLA degradation. However, this regulation is absent in non-vascular land plants, which lack active gibberellins or a proper GID1 receptor. Current knowledge indicates that DELLAs are important pieces of the signalling machinery of vascular plants, especially angiosperms, but nothing is known about DELLA function during early land plant evolution or if they exist at all in charophytan algae. We have now elucidated the evolutionary origin of DELLA proteins, showing that algal GRAS proteins are monophyletic and evolved independently from those of land plants, which explains why there are no DELLAs outside land plants. DELLA genes have been maintained throughout land plant evolution with only two major duplication events kept among plants. Furthermore, we show that the features needed for DELLA interaction with the receptor were already present in the ancestor of all land plants, and propose that these DELLA N-terminal motifs have been tightly conserved in non-vascular land plants for their function in transcriptional co-activation, which allowed subsequent exaptation for the interaction with the GID1 receptor when vascular plants developed gibberellin synthesis and the corresponding perception module.

[EN] Asymmetric auxin distribution is instrumental for the differential growth that causes organ bending on tropic stimuli and curvatures during plant development. Local differences in auxin concentrations are achieved mainly by polarized cellular distribution of PIN auxin transporters, but whether other mechanisms involving auxin homeostasis are also relevant for the formation of auxin gradients is not clear. Here we show that auxin methylation is required for asymmetric auxin distribution across the hypocotyl, particularly during its response to gravity. We found that loss-of-function mutants in Arabidopsis IAA CARBOXYL METHYLTRANSFERASE1 (IAMT1) prematurely unfold the apical hook, and that their hypocotyls are impaired in gravitropic reorientation. This defect is linked to an auxin-dependent increase in PIN gene expression, leading to an increased polar auxin transport and lack of asymmetric distribution of PIN3 in the iamt1 mutant. Gravitropic reorientation in the iamt1 mutant could be restored with either endodermis-specific expression of IAMT1 or partial inhibition of polar auxin transport, which also results in normal PIN gene expression levels. We propose that IAA methylation is necessary in gravity-sensing cells to restrict polar auxin transport within the range of auxin levels that allow for differential responses.

This article presents the design and construction of a wireless electrocardiograph of one derivation using active electrodes, the stages of adequacy of the signal originated from the electrodes, the digitization stage, digital filtering, transmission using Bluetooth towards an Android mobile device, where there is located an apk which was developed using the IDE Processing, are described. The tests determine that noise and harmonic distortion do not affect in a significant way the system, also prove a right functionality from the system through comparisons made using signal to noise ratio (SNR), total harmonic distortion (THD) and signal to noise ratio and distortion (SINAD) from multiple electrocardiography signals which were acquire by the prototype and a Cassy Sensor ECG device used as a reference., Este artículo presenta el diseño y construcción de un electrocardiógrafo inalámbrico de una derivación utilizando electrodos activos, donde se describen las etapas de adecuación de la señal proveniente de los electrodos, la etapa de digitalización, filtrado digital y transmisión vía Bluetooth hacia un dispositivo móvil con sistema operativo Android, donde se encuentra alojado un apk, el cual fue desarrollado utilizando el IDE Processing. En las pruebas realizadas se logra determinar que el ruido y la distorsión causada por armónicos no afectan de manera significativa el sistema, además se evidencia un correcto funcionamiento de éste mediante la comparación de las relaciones de señal a ruido (NSR), distorsión armónica total (THD) y relación señal a ruido y distorsión (SINAD) de las señales electrocardiográficas adquiridas por el dispositivo y un equipo Sensor de ECG Cassy empleado como referencia

DELLA proteins are transcriptional regulators present in all land plants which have been shown to modulate the activity of over 100 transcription factors in Arabidopsis, involved in multiple physiological and developmental processes. It has been proposed that DELLAs transduce environmental information to pre-wired transcriptional circuits because their stability is regulated by gibberellins (GAs), whose homeostasis largely depends on environmental signals. The ability of GAs to promote DELLA degradation coincides with the origin of vascular plants, but the presence of DELLAs in other land plants poses at least two questions: what regulatory properties have DELLAs provided to the behavior of transcriptional networks in land plants, and how has the recruitment of DELLAs by GA signaling affected this regulation. To address these issues, we have constructed gene co-expression networks of four different organisms within the green lineage with different properties regarding DELLAs: Arabidopsis thaliana and Solanum lycopersicum (both with GA-regulated DELLA proteins), Physcomitrella patens (with GA-independent DELLA proteins) and Chlamydomonas reinhardtii (a green alga without DELLA), and we have examined the relative evolution of the subnetworks containing the potential DELLA-dependent transcriptomes. Network analysis indicates a relative increase in parameters associated with the degree of interconnectivity in the DELLA-associated subnetworks of land plants, with a stronger effect in species with GA-regulated DELLA proteins. These results suggest that DELLAs may have played a role in the coordination of multiple transcriptional programs along evolution, and the function of DELLAs as regulatory ‘hubs’ became further consolidated after their recruitment by GA signaling in higher plants.

[EN] DELLA proteins are transcriptional regulators present in all land plants which have been shown to modulate the activity of over 100 transcription factors in Arabidopsis, involved in multiple physiological and developmental processes. It has been proposed that DELLAs transduce environmental information to pre-wired transcriptional circuits because their stability is regulated by gibberellins (GAs), whose homeostasis largely depends on environmental signals. The ability of GAs to promote DELLA degradation coincides with the origin of vascular plants, but the presence of DELLAs in other land plants poses at least two questions: what regulatory properties have DELLAs provided to the behavior of transcriptional networks in land plants, and how has the recruitment of DELLAs by GA signaling affected this regulation. To address these issues, we have constructed gene co-expression networks of four different organisms within the green lineage with different properties regarding DELLAs: Arabidopsis thaliana and Solanum lycopersicum (both with GA- regulated DELLA proteins), Physcomitrella patens (with GA- independent DELLA proteins) and Chlamydomonas reinhardtii (a green alga without DELLA), and we have examined the relative evolution of the subnetworks containing the potential DELLA-dependent transcriptomes. Network analysis indicates a relative increase in parameters associated with the degree of interconnectivity in the DELLA-associated subnetworks of land plants, with a stronger effect in species with GA- regulated DELLA proteins. These results suggest that DELLAs may have played a role in the coordination of multiple transcriptional programs along evolution, and the function of DELLAs as regulatory 'hubs' became further consolidated after their recruitment by GA signaling in higher plants.

High temperature is a general stress factor that causes a decrease in crop yield. It has been shown that auxin application reduces the male sterility caused by exposure to higher temperatures. However, widespread application of a hormone with vast effects on plant physiology may be discouraged in many cases. Therefore, the generation of new plant varieties that locally enhance auxin in reproductive organs may represent an alternative strategy. We have explored the possibility of increasing indole-3-acetic acid (IAA) in ovaries by reducing IAA methyltransferase1 (IAMT1) activity in Arabidopsis thaliana. The iamt1 mutant showed increased auxin signalling in funiculi, which correlated with a higher growth rate of wild-type pollen in contact with mutant ovaries and premature ovule fertilization. While the production of seeds per fruit was similar in the wild type and the mutant at 20 °C, exposure to 29 °C caused a more severe decrease in fertility in the wild type than in the mutant. Loss of IAMT1 activity was also associated with the production of more nodes after flowering and higher tolerance of the shoot apical meristem to higher temperatures. As a consequence, the productivity of the iamt1 mutant under higher temperatures was more than double of that of the wild type, with almost no apparent trade-off.

DELLA proteins are transcriptional regulators present in all land plants which have been shown to modulate the activity of over 100 transcription factors in Arabidopsis, involved in multiple physiological and developmental processes. It has been proposed that DELLAs transduce environmental information to pre-wired transcriptional circuits because their stability is regulated by gibberellins (GAs), whose homeostasis largely depends on environmental signals. The ability of GAs to promote DELLA degradation coincides with the origin of vascular plants, but the presence of DELLAs in other land plants poses at least two questions: what regulatory properties have DELLAs provided to the behavior of transcriptional networks in land plants, and how has the recruitment of DELLAs by GA signaling affected this regulation. To address these issues, we have constructed gene co-expression networks of four different organisms within the green lineage with different properties regarding DELLAs: Arabidopsis thaliana and Solanum lycopersicum (both with GA-regulated DELLA proteins), Physcomitrella patens (with GA-independent DELLA proteins) and Chlamydomonas reinhardtii (a green alga without DELLA), and we have examined the relative evolution of the subnetworks containing the potential DELLA-dependent transcriptomes. Network analysis indicates a relative increase in parameters associated with the degree of interconnectivity in the DELLA-associated subnetworks of land plants, with a stronger effect in species with GA-regulated DELLA proteins. These results suggest that DELLAs may have played a role in the coordination of multiple transcriptional programs along evolution, and the function of DELLAs as regulatory ‘hubs’ became further consolidated after their recruitment by GA signaling in higher plants

[EN] The circadian clock is known to gate gibberellin signalling in plants through transcriptional control of the GA receptor genes GID1a and GID1b. Here, we show that the TOC1/PRR components of the Arabidopsis circadian clock could be binding directly the GID1b promoter to modulate GA sensing, [ES] En plantas, el reloj circadiano modula la señalización de giberelinas mediante el control transcripcional de los genes de receptores de GAs GID1a y GID1b. Aquí mostramos cómo las proteínas del reloj circadiano de Arabidopsis TOC1/PRR, modulan la percepción de GAs probablemente por la unión directa al promotor de GID1b

Introduction: Puerperal infection constitutes one of the most three relevant causes of maternal and perinatal mortality. Objective: To characterize the epidemiological factors in puerperal infections at “Abel Santamaria Cuadrado” University Hospital, Pinar del Rio during a three-year period (2006-2008). Material andMethods: A cross sectional, retrospective and analytical (case-control) research was carried out. The totality of puerperae during this period (15101) constituted the target group, and the sample was comprised of study group represented by the puerperae with puerperal infection (n= 62), and the control group by three healthy puerperae (consecutively to the case study) according to the birth registers (186). Results: The main risk factors identified were: time of membrane rupture between 12 -36 hours (OR=4, 75), caesarean section (OR= 2,96), failed induction (OR= 2, 67) and patients with several vaginal examinations (OR= 2, 26). The time of membrane rupture between 12-36 hours was statistically significant as well as caesarean section (X2 =27,6; X2 = 6,02 respectively) in relation to puerperal infection. Conclusion: Puerperal endometriosis was an important obstetric cause to admit the patients in the Intensive Care Units due to the severe maternal morbidity., ntroducción: La infección puerperal constituye una de las tres causas más relevantes de mortalidad materna y perinatal. Objetivo: Caracterizar los factores epidemiológicos de la infección puerperal en el Hospital General “Abel Santamaría Cuadrado” de Pinar del Río durante el trienio 2006 – 2008. Material y métodos: Se realizó una investigación transversal, retrospectiva y analítica (caso- control). El universo estuvo representado por la totalidad de las puérperas durante ese período (15101), y la muestra conformada por un grupo estudio representado por las puérperas con diagnóstico de infección puerperal (n= 62), y el grupo control por las tres puérperas sanas consecutivas al caso estudio según el registro de nacimientos (186). Resultados: Los principales factores de riesgo identificados fueron: el tiempo de rotura de membrana entre 12 y 36 horas (OR= 4,75), la cesárea primitiva (OR= 2,96), la inducción fallida (OR= 2,67) y la paciente politactada (OR= 2, 26).Resultó estadísticamente significativo el tiempo de rotura de membrana entre 12 y 36 horas y la operación cesárea (X2 =27,6; X2 = 6,02 respectivamente) con relación a la infección puerperal. Conclusiones: La endometritis puerperal constituyó una causa obstétrica importante como morbilidad materna grave para el ingreso en la Unidad de Cuidados Intensivos.

The weight at birth is related to the development of the child and its possible adaptation to the environment. The prognosis of those with low birth weight is enough for trying to prevent and it is important to know its causes. In Pinar del Río it has been a latent problem since a long time ago. The present work pretends to identify the current risk factors of the low birth weight. A study of cases and controls with two groups of pregnants was conducted: a study group (n = 25) including all mothers with low weight newborns; a control group (n = 100) with mothers with normotensive children at birth during January to December, 2006 in Reparto Hermanos Cruz. Pinar del Río. For obtaining data, the medical records, the consultation records and emergencies were evaluated. The age besides maternal malnutrition and the insufficient increase of the body weight during the gestational period, both in adolescent pregnants or not were considered as associated riskfactors. The inadequate alimentary habits influenced on the Low Birth Weight in the two groups studied. The bad socioeconomic conditions had a great impact on the Low Birth Weight in all cases, El peso al nacer se relaciona con el desarrollo del niño y su posible adaptación al ambiente. El pronóstico de los nacidos con bajo peso es motivo suficiente para tratar de prevenirlo y para ello, es importante el conocimiento de sus causas. En Pinar de Río ha sido un problema latente desde hace muchos años. En el presente trabajo se pretende identificar factores de riesgo actuales del bajo peso al nacer. Se realizó un estudio de casos y controles con dos grupos de gestantes: grupo estudio (n = 25) con todas las madres con recién nacidos bajo peso; un grupo control (n=100) conformado por mujeres con hijos normopesos al nacer, durante el período enero – diciembre del 2006 en el Reparto “Hermanos Cruz” del Municipio dePinar del Río. Para la obtención de datos fueron evaluadas las historias clínicas, registros de consultación y urgencias. Se consideraron como factores de riesgo asociados: la edad, además de la desnutrición materna y la insuficiente ganancia de peso durante la gestación, tanto en madres adolescentes como no adolescentes. Los malos hábitos alimentarios influyeron en la aparición del Bajo Peso al Nacer en los dos grupos estudiados. Las malas condiciones socioeconómicas impactaron negativamente sobre la aparición del Bajo Peso al Nacer en todos los casos.