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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.

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]

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. Seed formation requires a coordinated development of its three parts: embryo, endosperm and seed coat. The plant hormones brassinosteroids contribute this this coordination by influencing how different seed components perceive each other's growth. [ABSTRACT FROM AUTHOR]

Since the discovery of brassinolide in the pollen of rapeseed, brassinosteroids (BRs) have consistently been associated with reproductive traits. However, compared to what is known for how BRs shape vegetative development, the understanding of how these hormones regulate reproductive traits is comparatively still lacking. Nevertheless, there is now considerable evidence that BRs regulate almost all aspects of reproduction, from ovule and pollen formation to seed and fruit development. Here, we review the current body of knowledge on how BRs regulate reproductive processes in plants and what is known about how these pathways are transduced at the molecular level. We also discuss how the manipulation of BR biosynthesis and signaling can be a promising avenue for improving crop traits that rely on efficient reproduction. We thus propose that BRs hold an untapped potential for plant breeding, which could contribute to attaining food security in the coming years. [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.

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]

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.