The tomato receptor CuRe1 senses a cell wall protein to identify Cuscuta as a pathogen
Hegenauer et al. show a molecular mechanism of how plants can sense parasitic Cuscuta. They isolated an 11 kDa protein of the parasite cell wall and identified it as a glycine-rich protein (GRP). This GRP, as well as its minimal peptide epitope Crip21, serve as a pathogen-associated molecular pattern and specifically bind and activate a membrane-bound immune receptor of tomato, the Cuscuta Receptor 1 (CuRe1), leading to defense responses in resistant hosts. These findings provide the initial steps to understand the resistance mechanisms against parasitic plants and further offer great potential for protecting crops by engineering resistance against parasitic plants.
Evolutionary dynamics of genome size in a radiation of woody plants
Moeglein et al. discovered nine independent polyploidization events, two reductions in base chromosome number, and substantial variation in genome size with a slight trend toward genome size reduction in polyploids. They did not find strong relationships between genome size and the functional and morphological traits that have been highlighted at broader phylogenetic scales.
American Journal of Botany
Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2
Walker et al. synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2] (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre‐industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain.
[REDUX] Origins and evolution of cuticle biosynthetic machinery in land plants
Kong et al. performed a comparative genomic analysis of core components that mediate cuticle biosynthesis, and characterized the chemical compositions and physiological parameters of cuticles from a broad set of embryophytes. Phylogenomic analysis revealed that the cuticle biosynthetic machinery originated in the last common ancestor of embryophytes. Co-expansion and coordinated expression are evident in core genes involved in the biosynthesis of two major cuticle components: the polymer cutin and cuticular waxes.
Set ambitious goals for biodiversity and sustainability
In response to the goals proposed in the draft post-2020 Global Biodiversity Framework (GBF) made public by the CBD, Diaz et al. urge negotiators to consider three points that are critical if the agreed goals are to stabilize or reverse nature's decline. First, multiple goals are required because of nature's complexity, with different facets—genes, populations, species, deep evolutionary history, ecosystems, and their contributions to people—having markedly different geographic distributions and responses to human drivers. Second, interlinkages among these facets mean that goals must be defined and developed holistically rather than in isolation, with potential to advance multiple goals simultaneously and minimize trade-offs between them. Third, only the highest level of ambition in setting each goal, and implementing all goals in an integrated manner, will give a realistic chance of stopping—and beginning to reverse—biodiversity loss by 2050.
Oxygen-sensing mechanisms across eukaryotic kingdoms and their roles in complex multicellularity
In our current oxygen-rich atmosphere, the ability of eukaryotic cells to sense variation in oxygen concentrations is essential for adapting to low-oxygen conditions. However, Earth's atmosphere has not always contained such high oxygen concentrations. Hammarlund et al. discuss oxygen-sensing systems across both plants and animals and argue that the systems are functionally convergent and that their emergence in an initially hypoxic environment shaped how they operate today.
V.PhyloMaker: an R package that can generate very large phylogenies for vascular plants
Jin and Qian present V.PhyloMaker, a freely available package for R designed to generate phylogenies for vascular plants. The mega‐tree implemented in V.PhyloMaker (i.e. GBOTB.extended.tre), which was derived from two recently published mega‐trees and includes 74 533 species and all families of extant vascular plants, is the largest dated phylogeny for vascular plants. V.PhyloMaker can generate phylogenies for very large species lists (the largest species list that we tested included 314 686 species). V.PhyloMaker generates phylogenies at a fast speed, much faster than other phylogeny‐generating packages.
Plant genomes: Markers of evolutionary history and drivers of evolutionary change
Soltis and Soltis describe how plant genomes have been harnessed for studies of plant phylogeny and diversification, with examples spanning all green plants, a clade of nearly half a million species spanning nearly a billion years of evolutionary time. Then focusing on angiosperms, they suggest how the process of whole‐genome duplication (polyploidy) has driven, and continues to drive, major innovations in morphology, stress response, and more. Together, these perspectives will begin to reveal how genomic change can lead to novelty and diversity at the organismal level.
Plants People Planet
The effects of drought on plant–pollinator interactions: What to expect? - ScienceDirect
Although a majority of flowering plants (87 % of all angiosperms) is insect-pollinated, the effects of drought on plant–pollinator interactions are not well studied. However, plant pollination and reproduction phases are highly sensitive to this abiotic stress. At plant individual scale, Descamps et al. hypothesize that drought will alter plant–pollinator interactions via (i) signals or cues for insect visitors (floral display, plant height, number of flowers per plant, flower color, shape and size, olfactory compound quantity and composition) and (ii) floral rewards (nectar volume, total sugar concentration, sugar composition, pollen quantity and chemical composition). In this review, they synthesize evidence related to the effects of drought on floral signals and rewards, and discuss how they may disrupt plant–pollinator relationships.
Environmental and Experimental Botany
A TAL effector-like protein of an endofungal bacterium increases the stress tolerance and alters the transcriptome of the host
Endosymbiotic bacteria are found in diverse fungi, but little is known about how they communicate with their hosts. Some plant pathogenic bacteria use type III-translocated TAL effectors to control host transcription, and TAL-like proteins are encoded in genomes of the fungal endosymbiotic bacterium Mycetohabitans rhizoxinica. Carter et al. present evidence that these proteins are, like TAL effectors, type III-secreted, nuclear-localizing effectors that perturb host transcription and show that one enhances tolerance of the fungal host to cell membrane stress.