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Abstract An angiosperm seed is formed by the embryo and endosperm, which are direct products of fertilization, and by the maternal seed coat. These tissues communicate with each other to ensure synchronized seed development. After fertilization, auxin produced in the endosperm is exported to the integuments where it drives seed coat formation. Here, we show that the seed coat signals back to the endosperm to promote its proliferation via the steroid hormones brassinosteroids (BR). We show that BR regulate cell wall-related processes in the seed coat and that the biophysical properties of this maternal organ determine the proliferation rate of the endosperm in a manner independent of the timing of its cellularization. We thus propose that maternal BR signaling tunes endosperm proliferation to seed coat expansion.

Jubby Marcela Galvez,1 Carlos Martin Restrepo,1 Nora Constanza Contreras,1 Clara Alvarado,1 Carlos-Alberto Calderón-Ospina,1 Nidia Peña,1 Ricardo A Cifuentes,2 Daniela Duarte,1 Paul Laissue,1 Dora Janeth Fonseca1 1GENIUROS Research Group, Center For Research in Genetics and Genomics – CIGGUR, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia; 2Area of Basic Sciences, College of Medicine, Universidad Militar Nueva Granada, Bogotá, Colombia Purpose: Warfarin is an oral anticoagulant associated with adverse reaction to drugs due to wide inter- and intra-individual dosage variability. Warfarin dosage has been related to non-genetic and genetic factors. CYP2C9 and VKORC1 gene polymorphisms affect warfarin metabolism and dosage. Due to the central role of populations’ ethnical and genetic origin on warfarin dosage variability, novel algorithms for Latin American subgroups are necessary to establish safe anticoagulation therapy.Patients and methods: We genotyped CYP2C9*2 (c.430C > T), CYP2C9*3 (c.1075A > C), CYP4F2 (c.1297G > A), and VKORC1 (-1639 G > A) polymorphisms in 152 Colombian patients who received warfarin. We evaluated the impact on the variability of patients’ warfarin dose requirements. Multiple linear regression analysis, using genetic and non-genetic variables, was used for creating an algorithm for optimal warfarin maintenance dose.Results: Median weekly prescribed warfarin dosage was significantly lower in patients having the VKORC1-1639 AA genotype and poor CYP2C9*2/*2,*2/*3 metabolizers than their wild-type counterparts. We found a 2.3-fold increase in mean dose for normal sensitivity patients (wild-type VKORC1/CYP2C9 genotypes) compared to the other groups (moderate and high sensitivity); 31.5% of the patients in our study group had warfarin sensitivity-related genotypes. The estimated regression equation accounted for 44.4% of overall variability in regard to warfarin maintenance dose. The algorithm was validated, giving 45.9% correlation (R2=0.459).Conclusion: Our results describe and validate the first algorithm for predicting warfarin maintenance in a Colombian mestizo population and have contributed toward the understanding of pharmacogenetics in a Latin American population subgroup.Keywords: genetic polymorphism, adverse drug reaction, gene frequency, anticoagulants

MADS-box transcription factors (TFs) are ubiquitous in eukaryotic organisms and play major roles during plant development. Nevertheless, their function in seed development remains largely unknown. Here, we show that the imprinted Arabidopsis thaliana MADS-box TF PHERES1 (PHE1) is a master regulator of paternally expressed imprinted genes, as well as of non-imprinted key regulators of endosperm development. PHE1 binding sites show distinct epigenetic modifications on maternal and paternal alleles, correlating with parental-specific transcriptional activity. Importantly, we show that the CArG-box-like DNA-binding motifs that are bound by PHE1 have been distributed by RC/Helitron transposable elements. Our data provide an example of the molecular domestication of these elements which, by distributing PHE1 binding sites throughout the genome, have facilitated the recruitment of crucial endosperm regulators into a single transcriptional network.

In flowering plants, seed development is initiated by the fusion of the maternal egg and central cells with two paternal sperm cells, leading to the formation of embryo and endosperm, respectively. The fertilization products are surrounded by the maternally derived seed coat, whose development prior to fertilization is blocked by epigenetic regulators belonging to the Polycomb Group (PcG) protein family. Here we show that fertilization of the central cell results in the production of auxin and most likely its export to the maternal tissues, which drives seed coat development by removing PcG function. We furthermore show that mutants for the MADS-box transcription factor AGL62 have an impaired transport of auxin from the endosperm to the integuments, which results in seed abortion. We propose that AGL62 regulates auxin transport from the endosperm to the integuments, leading to the removal of the PcG block on seed coat development.

Several pathways control time to flowering in Arabidopsis thaliana through transcriptional and posttranscriptional gene regulation. In recent years, mRNA processing has gained interest as a critical regulator of flowering time control in plants. However, the molecular mechanisms linking RNA splicing to flowering time are not well understood. In a screen for Arabidopsis early flowering mutants we identified an allele of BRR2a. BRR2 proteins are components of the spliceosome and highly conserved in eukaryotes. Arabidopsis BRR2a is ubiquitously expressed in all analyzed tissues and involved in the processing of flowering time gene transcripts, most notably FLC. A missense mutation of threonine 895 in BRR2a caused defects in FLC splicing and greatly reduced FLC transcript levels. Reduced FLC expression increased transcription of FT and SOC1 leading to early flowering in both short and long days. Genome-wide experiments established that only a small set of introns was not correctly spliced in the brr2a mutant. Compared to control introns, retained introns were often shorter and GC-poor, had low H3K4me1 and CG methylation levels, and were often derived from genes with a high-H3K27me3-low-H3K36me3 signature. We propose that BRR2a is specifically needed for efficient splicing of a subset of introns characterized by a combination of factors including intron size, sequence and chromatin, and that FLC is most sensitive to splicing defects.

En la zona de vega del río Arauca, en el municipio de Arauquita, durante el semestre 8-95, se evaluaron 25 líneas de fríjol caraota, suministradas por el Programa de Fríjol del CIAT y un material local. La región se encuentra a 155 m.s.n.m., con una temperatura media de 27°C y precipitación pluvial promedia anual de 2410 mm. Se utilizó un diseño de bloques completos al azar con cuatro repeticiones y una densidad de población de 133.333 plantas por hectárea. Los genotipos evaluados, presentaron para el rendimiento de grano (14% de humedad), una oscilación entre 253 Kg./Ha (ARA13), Y 2290 Kg"/Ha (NAG 313). Estadísticamente, siete genotipos fueron superiores al testigo local, el cual rindió 1604 Kg"/Ha y 19 genotipos superiores al testigo internacional usado por el CIAT (Jamapa), el cual rindió 996 Kg"/Ha. En cuanto al número de días a floración y días a madurez fisiológica, los genotipos evaluados fueron muy similares, con un promedio de 39 días y 75 días, respectivamente. En las variables número de vainas por planta, número de granos por vaina y peso de 100 granos, se observaron diferencias altamente significativas entre genotipos.In Arauquita in semester 11/95, were evaluated 25 genotypes of black bean, supplied by CIAT bean program and a local genotype. Arauquita is 155 meters over the sea level, average temperature 270C and rainfall annual average of 2410 mm. The genotypes were evaluated in a two wayclassification design with four repetitions and density of 133.333 plants/Ha. The grain yield (14% humidity) oscillated between 253 and 2290 Kg"/Ha. Seven genotypes were better than local witness, which yielded 1604 Kg"/Ha, and nineteen genotypes better than CIAT international witness (JAMAPA), which yielded 996 Kg"/Ha. With respect to number days to flowerinq and physiological maturity, the genotypes were very similar, with 39 and 75 days respectly. The number of seaths per plant, grains per seath and 100 grains weight, were differents among genotypes.

El cultivo del fríjol negro o caraota constituye un importante renglón agrícola de impacto económico y social en el municipio de Arauquita (Arauca), donde cerca de 500 hectáreas se destinan para su siembra en los mesessecos de Octubre y Noviembre. En este municipio la caraota es un cultivo tradicional, en el cual se emplea poca tecnología y existe poca investigación. El producto se comercializa, principalmente, en Venezuela donde existe una alta demanda. Para analizar la Tecnología Local de Producción (TLP), se realizaron encuestas entre agricultores representativos en diferentes veredas del municipio de Arauquita, encontrándose que es un cultivo en donde la mano de obra es contratada con personal de la región y cuyas labores se resumen en: siembra"a chuzo" sobre terrenos previamente quemados, el control de malezas, y finalmente cosecha y beneficio.En la cadena de comercialización entre Colombia y Venezuela existen por lo menos 7 pasos entre el productor y el consumidor final.The black bean crop is an important economic and social activity in Arauquita (east of Colombia). In thal region, about 500 hectares are devoted to planting seeds in dry months (October-November). This is a traditional crop, wich used not much technology and there is little research. The product is marketed mainly in Venezuela, where it has high demando This study was carried out making surveys to representative farmers on the region. In the black bean crop the farms work are contracted with personal of the region and its agricultural practices in summary are: burn of the vegetation, sowing, wich is done to random hill ("chuzo"), putting several seeds by hill. Except the control of weeds, no fitosanitary control is done, isn't fertilized and its harvest and thresh are manual. Marketing between Colombia and Venezuela has at least seven steps from the producer to final costumer.

Magnetic structure factor (MSF), calculated from ground state configuration previously obtained by Monte Carlo simulation in different rectangular artificial spin ices, is employed to investigate ground state degeneracy. Our analysis considers the importance of nanoislands size to the ratio between rectangle sides in the lattice parameters via a dumbbell model. Pinch points in MSF along with residual entropy, determined for a number of different rectangular lattices with disconnected nanoislands, point out the conditions for the emergency of a gauge field, through which magnetic monopoles interact effectively. [ABSTRACT FROM AUTHOR]

SUMMARY: The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies. Significance Statement: Within seeds a specialized structure is responsible for nourishing the embryo during its development. These nourishing tissues are also important sources of staple foods and feed. Here, we provide gene expression datasets of nourishing tissues of early diverging angiosperms, and use this information for a meta‐analysis to identify pathways conserved, or divergent, throughout evolution. Thus, we aim to provide a resource for gene discovery for seed biology studies. [ABSTRACT FROM AUTHOR]

DREB1/CBF genes, known as major regulators of plant stress responses, are rapidly and transiently induced by low temperatures. Using a yeast one-hybrid screening, we identified a putative Phytochrome-Interacting bHLH Factor (OsPIF14), as binding to the OsDREB1B promoter. bHLH proteins are able to bind to hexameric E-box (CANNTG) or N-box (CACG(A/C)G) motifs, depending on transcriptional activity. We have shown that OsPIF14 binds to the OsDREB1B promoter through two N-boxes and that the flanking regions of the hexameric core are essential for protein-DNA interaction and stability. We also showed that OsPIF14 down-regulates OsDREB1B gene expression in rice protoplasts, corroborating the OsPIF14 repressor activity observed in the transactivation assays using Arabidopsis protoplasts. In addition, we showed that OsPIF14 is indeed a phytochrome interacting factor, which preferentially binds to the active form (Pfr) of rice phytochrome B. This raises the possibility that OsPIF14 activity might be modulated by light. However, we did not observe any regulation of the OsDREB1B gene expression by light under control conditions. Moreover, OsPIF14 gene expression was shown to be modulated by different treatments, such as drought, salt, cold and ABA. Interestingly, OsPIF14 showed also a specific cold-induced alternative splicing. All together, these results suggest the possibility that OsPIF14 is involved in cross-talk between light and stress signaling through interaction with the OsDREB1B promoter. Although in the absence of stress, OsDREB1B gene expression was not regulated by light, given previous reports, it remains possible that OsPIF14 has a role in light modulation of stress responses.

Titanium dioxide (TiO2) films were deposited by spin coating on metallic and oxidized aluminum substrates. Surface oxidation was performed by electrochemical anodizing of Al plates in solution composed by H2SO2 and deionized water. The TiO2 layers and substrates were investigated by mechanical profilometry, X-ray diffraction, field emission scanning electron microscope, X-ray photoelectron spectroscopy, and four-point probe method in order to evaluate the effect of the substrate oxidation on morphology, crystalline structure, chemical composition, and electrical properties of the TiO2 films. Results show that deposited films are chemically stable, thick, porous, with anatase preferential orientation and more electrically conductive when grown on metallic surfaces, which is an important feature to decrease the internal resistance of photoelectric devices. [ABSTRACT FROM AUTHOR]