Jacobs Singer (bonsaiporter0)
Le Roux et al. suggest that documented increases in local plant richness in response to climate change should consider the nature of 'new' species. They find that species responsible for increases in richness in areas that have experienced significant disturbance and climate change are often invasive and/or weedy species. Bonacorsi et al. describe a new fossil from the Early Devonian that provides the earliest clear evidence for more advanced reproductive biology in land plants. The plant produced multiple spore size classes, which is an essential innovation necessary for all advanced plant reproductive strategies, including seeds and flowers. In this Primer, Sunyer and Trepat introduce durotaxis, the mode of migration by which cells follow gradients of extracellular matrix stiffness. Best known for their culinary value, truffles are lineages that belongs to the Ascomycete fungi. M.-A. Selosse explores the biology underlying their distinct features. BMP (bone morphogenetic protein) signaling activity is precisely controlled by both pathway agonists and antagonists. Here, we identify a previously unrecognized BMP signaling antagonist. We demonstrate that the Drosophila BMP type I receptor Sax (Saxophone) functions as a Dpp (Decapentaplegic) receptor in Drosophila embryos, but that its activity is normally inhibited by the O-linked glycosyltransferase Sxc (Super sex combs). In wild-type embryos, Sax activity is inhibited, and the BMP type I receptor Tkv (Thickveins) is the sole conduit for Dpp. In contrast, in sxc mutants, the Dpp signal is transduced by both Tkv and Sax, and elevated Dpp signaling results in embryonic lethality. We also demonstrate that Sxc O-glycosylates Sax and observe elevated Dpp signaling in response to maternal restriction of dietary sugar. These findings link fertility to nutritive environment and point to Sax signaling as the nutrient-sensitive branch of BMP signaling. The cardiac neural crest arises in the hindbrain, then migrates to the heart and contributes to critical structures, including the outflow tract septum. Chick cardiac crest ablation results in failure of this septation, phenocopying the human heart defect persistent truncus arteriosus (PTA), which trunk neural crest fails to rescue. Here, we probe the molecular mechanisms underlying the cardiac crest's unique potential. Transcriptional profiling identified cardiac-crest-specific transcription factors, with single-cell RNA sequencing revealing surprising heterogeneity, including an ectomesenchymal subpopulation within the early migrating population. Loss-of-function analyses uncovered a transcriptional subcircuit, comprised of Tgif1, Ets1, and Sox8, critical for cardiac neural crest and heart development. Importantly, ectopic expression of this subcircuit was sufficient to imbue trunk crest with the ability to rescue PTA after cardiac crest ablation. Together, our results reveal a transcriptional program sufficient to confer cardiac potential onto trunk neural crest cells, thus implicating new genes in cardiovascular birth defects. Centrosomes break symmetry in the C. elegans one-cell embryo, triggering its anterior-posterior polarization and initiating segregation of somatic and germline cell lineages. In this issue of Developmental Cell, De Henau et al. show that mitochondria also contribute to symmetry breaking by producing hydrogen peroxide at the egg's future posterior pole. Topographic map development requires precise coordination between navigating axons and their targets in a dynamic environment. In this issue of Developmental Cell, Isabella et al. describe a mechanism in which a changing gradient of the morphogen retinoic acid regulates the expression of guidance factors to shape topographic axon targeting. Neural crest cells have different developmental potencies at different levels along the body axis of the embryo. In this issue of Developmental Cell, Gandhi et al. identify transcriptio
