Editors' Choice

Science  20 Apr 2018:
Vol. 360, Issue 6386, pp. 281
  1. Plant Microbiology

    Tuning the soil for growth

    1. Gemma Alderton

    Plant root chemicals manipulate microbes in the soil.

    PHOTO: PHIL DEGGINGER/SCIENCE SOURCE

    Plant roots in soil are often regions of high microbial activity, known as rhizospheres, where symbiosis between plants and microbes promote plant growth. The composition of rhizosphere microbiomes is influenced by diverse factors. To find out how the various chemicals in root exudate affect the rhizosphere, Zhalnina et al. examined the wild oat grass Avena barbata. At different stages of the plant's development, different chemicals were produced, and different bacteria responded to them. This “metabolic synchronization” provides insight into how plants manipulate the rhizosphere microbiome.

    Nat. Microbiol. 3, 470 (2018).

  2. Single-Cell Genomics

    Tying genotype to phenotype, cell by cell

    1. Laura M. Zahn

    RNA transcripts can now be sequenced within single cells. Such studies identify variants that affect gene expression at a level that may not be detected by bulk sequencing. Van der Wijst et al. sequenced ∼25,000 individual blood cells from 45 individuals. Expression quantitative trait loci that had previously been identified in bulk studies were found, which helped validate the approach. An additional 287 genes were identified that showed differences in expression in single cells resulting from genetic variation, 48 of which differed among cell types. Furthermore, single-cell sequencing detected variants that affect regulatory networks and revealed personalized coexpression patterns.

    Nat. Genet. 10.1038/s41588-018-0089-9 (2018).

  3. Microbiology

    Weathering life after death

    1. Caroline Ash

    Tombstone encrustation is influenced by rock chemistry.

    PHOTO: STAN PRITCHARD/ALAMY STOCK PHOTO

    Life is tough on rock exposed to ultraviolet radiation and extreme desiccation, and food is scarce. But microbial life does get a grip, and it contributes substantially to rock weathering by harvesting minerals for metabolism. Brewer and Fierer sampled 149 gravestones from Europe and the Americas and used marker-gene and shotgun metagenomic sequencing to uncover what was living on them. Geography, climate, and rock type were the main determinants of the microbial communities. Granite-based organisms were genetically geared for acid tolerance and mobility, whereas limestone-based communities tended to live in lichen associations, fix carbon, and resist radiation. Many of the communities were symbiotic or endolithic, indicating that some recourse to food and shelter is available even on the smoothest slab.

    Environ. Microbiol. 20, 958 (2018).

  4. Ice Sheets

    Explaining uneven mass loss

    1. H. Jesse Smith

    The Greenland Ice Sheet, along with the Antarctic Ice Sheet and glaciers worldwide, is melting at an accelerating rate. This melting is not uniform, however, with adjacent fjords often exhibiting quite different behaviors. What can account for those differences? Millan et al. present oceanographic observations and bathymetric data from the vicinity of 20 major glaciers in southeast Greenland, which show that retreating glaciers occupy deep valleys exposed to warm Atlantic water, whereas stable ones rest on sills away from warm water. These observations can explain the complex pattern of ice-front positions from the 1930s to the present.

    Geophys. Res. Lett. 10.1002/2017GL076561 (2018).

  5. Magnetism

    Manipulating an antiferromagnet

    1. Jelena Stajic

    Magnetic materials are routinely used in electronic devices, and the ability to change their magnetic state using electric fields is highly desirable. Most devices use ferromagnets—materials in which individual atomic spins all point in one direction—but there are important advantages to developing analogous devices with antiferromagnetic (AFM) materials. Liu et al. made thin films of the AFM MnPt3, a material that transitions from a noncollinear to a collinear AFM state a bit above room temperature. The thin films were grown on a ferroelectric substrate; applying an electric field to the substrate near the transition temperature changed the strain in the MnPt3 film, which in turn caused the film to change its spin structure from collinear to noncollinear.

    Nat. Electron. 1, 172 (2018).

  6. Metasurfaces

    Reconfigurable metasurfaces

    1. Ian S. Osborne

    The design flexibility in patterning metasurfaces allows many bulk optical components to be replaced with elements just a fraction of their thickness. For integrated optical devices or miniaturized lightweight components, metasurfaces offer a clear advantage over glass-based optics. By combining metasurface designs with arrays of electromechanically actuated microcantilevers, Zhao et al. demonstrate the ability to actively control the optical properties of a metasurface. Operating in the terahertz regime, they show that they can manipulate the polarization of transmitted light in real time to form a waveplate. Such active control of metasurface properties will be useful for developing imaging and sensing terahertz technologies.

    Optica 5, 303 (2018).

  7. Cancer

    Even more genes control cell growth

    1. L. Bryan Ray

    A full understanding of cancer evolution needs a systematic approach. Screening for genes that drive unrestrained proliferation of human cells could answer questions about the relative roles of mutations, gene dose, and tissue specificity in cancer development. To find those for which dosage changes could promote or inhibit cell proliferation, Sack et al. screened 16,000 genes in mammary, fibroblast, and pancreatic cells. They found nearly 400 genes that drove cell growth and more than 1000 that suppressed proliferation. Many expected genes that control the cell cycle were detected, but most of the identified genes were not previously known to regulate proliferation. Alterations in the somatic copy number of these genes in cancers indicate that they may contribute to tumorigenesis. Proliferation control depended strongly on cell type. Specific genetic-network architecture may be created during development in different cell types, perhaps through epigenetic control.

    Cell 10.1016/j.cell.2018.02.037 (2018).