Comprehensive 3D phenotyping reveals continuous morphological variation across genetically diverse sorghum inflorescences
Li et al. apply X‐ray computed tomography combined with detailed morphometrics, offering new imaging and computational tools to analyze three‐dimensional inflorescence architecture. To show the power of this approach, they focus on the panicles of Sorghum bicolor , which vary extensively in numbers, lengths, and angles of primary branches, as well as the three‐dimensional shape, size, and distribution of the seed.
The shapes of wine and table grape leaves: an ampelometric study inspired by the methods of Pierre Galet
Chitwood uses a saturating number of pseudo-landmarks to capture intricate, local features in grapevine leaves: the curvature of veins and the shapes of serrations. Using these points, averaged leaf shapes for 60 varieties of wine and table grapes are calculated that preserve features. A pairwise Procrustes distance matrix of the overall morphological similarity of each variety to the other classifies leaves into two main groups—deeply lobed and more entire—that correspond to the measurements of sinus depth by Pierre Galet. Using the system of Galet, pseudo-landmarks are converted into relative distance and angle measurements. Both Galet-inspired and Procrustean methods allow increased accuracy in predicting variety compared to a finite number of landmarks. Using Procrustean pseudo-landmarks captures grapevine leaf shape at the same level of detail as drawings and provides a quantitative method to arrive at mean leaf shapes representing varieties that can be used within a predictive statistical framework.
Heat stress response in the closest algal relatives of land plants reveals conserved stress signaling circuits
de Vries et al. explored the effect of heat stress in Mougeotia and Spirogyra , two representatives of Zygnematophyceae – the closest known algal sister lineage to land plants. Heat stress induced pronounced phenotypic alterations in their plastids, and high‐performance liquid chromatography‐tandem mass spectroscopy‐based profiling of 565 transitions for the analysis of main central metabolites revealed significant shifts in 43 compounds. They also analyzed the global differential gene expression responses triggered by heat, generating 92.8 Gbp of sequence data and assembling a combined set of 8905 well‐expressed genes. Each organism had its own distinct gene expression profile; less than one‐half of their shared genes showed concordant gene expression trends. They nevertheless detected common signature responses to heat such as elevated transcript levels for molecular chaperones, thylakoid components, and – corroborating our metabolomic data – amino acid metabolism. They also uncovered the heat‐stress responsiveness of genes for phosphorelay‐based signal transduction that links environmental cues, calcium signatures and plastid biology.
The Plant Journal
Horizontal gene transfer of Fhb7 from fungus underlies Fusarium head blight resistance in wheat
Fusarium head blight (FHB), caused by a fungus, reduces wheat crop yield and introduces toxins into the harvest. From the assembly of the genome of Thinopyrum elongatum, a wild relative of wheat used in breeding programs to improve cultivated wheat, Wang et al. cloned a gene that can address both problems. The encoded glutathione S-transferase detoxifies the trichothecene toxin and, when expressed in wheat, confers resistance to FHB.
Bumble bees damage plant leaves and accelerate flower production when pollen is scarce
Bumble bees rely heavily on pollen resources for essential nutrients as they build their summer colonies. Therefore, we might expect that annual differences in the availability of these resources must simply be tolerated, but Pashalidou et al. made observations suggesting that bees may have strategies to cope with irregular seasonal flowering. When faced with a shortage of pollen, bumble bees actively damaged plant leaves in a characteristic way, and this behavior resulted in earlier flowering by as much as 30 days. Experimenters were not able to fully replicate the results with their own damage, suggesting that there is a distinct method that the bees use to stimulate earlier flowering.
Genomic history and ecology of the geographic spread of rice
Gutaker et al. reconstruct the history of rice dispersal in Asia using whole-genome sequences of more than 1,400 landraces, coupled with geographic, environmental, archaeobotanical and paleoclimate data. Originating around 9,000 yr ago in the Yangtze Valley, rice diversified into temperate and tropical japonica rice during a global cooling event about 4,200 yr ago. Soon after, tropical japonica rice reached Southeast Asia, where it rapidly diversified, starting about 2,500 yr BP. The history of indica rice dispersal appears more complicated, moving into China around 2,000 yr BP. They also identify extrinsic factors that influence genome diversity, with temperature being a leading abiotic factor. ReadCube https://rdcu.be/b4ltY
Phylogenetic tree building in the genomic age
Kapli et al. discuss the major steps of phylogenetic analysis, including identification of orthologous genes or proteins, multiple sequence alignment, and choice of substitution models and inference methodologies. Understanding the different sources of errors and the strategies to mitigate them is essential for assembling an accurate tree of life.
Nature Reviews Genetics
Pollination by hoverflies in the Anthropocene
Doyle et al. contrast the roles of hoverflies and bees as pollinators, discuss the need for research and monitoring of different pollinator responses to anthropogenic change and examine emerging research into large populations of migratory hoverflies, the threats they face and how they might be used to improve sustainable agriculture.
Proceedings of the Royal Society B: Biological Sciences
Fungi are more dispersal-limited than bacteria among flowers
Vannette et al. compare the incidence and abundance of culturable flower-inhabiting bacteria and fungi among individual flowers. Using collections that span two coflowering communities across two years, they assess viable bacterial and fungal incidence and abundance within individual flower samples, and examine patterns across plant species that differ in flower traits. Their results demonstrate that bacteria can be detected in more flowers and in greater numerical abundance than fungi, particularly in flowers with more exposed corollas. For fungi, however, flowers with long corollas were equally likely as exposed flowers to contain cells, and hosted higher numbers of fungal cells, primarily yeasts. Across all flowers, bacteria and fungal incidence was positively related, but within flowers containing microbes, bacterial and fungal incidence was negatively related, suggesting shared dispersal routes but competition among microbes within flowers.
Long-term thermal sensitivity of Earth’s tropical forests
A key uncertainty in climate change models is the thermal sensitivity of tropical forests and how this value might influence carbon fluxes. Sullivan et al. measured carbon stocks and fluxes in permanent forest plots distributed globally. This synthesis of plot networks across climatic and biogeographic gradients shows that forest thermal sensitivity is dominated by high daytime temperatures. This extreme condition depresses growth rates and shortens the time that carbon resides in the ecosystem by killing trees under hot, dry conditions.