Current Biology最新文献

Capsicum (pepper) is among the most economically important species worldwide, and its fruits accumulate specialized metabolites with essential roles in plant environmental interaction and human health benefits as well as in conferring their unique taste. However, the genetics underlying differences in metabolite presence/absence and/or accumulation remain largely unknown. In this study, we carried out a genome-wide association study as well as generating and characterizing a novel backcross inbred line mapping population to determine the genetic architecture of the pepper metabolome. This genetic analysis provided over 1,000 metabolic quantitative trait loci (mQTL) for over 250 annotated metabolites. We identified 92 candidate genes involved in various mQTLs. Among the identified loci, we described and validated a gene cluster of eleven UDP-glycosyltransferases (UGTs) involved in monomeric capsianoside biosynthesis. We additionally constructed the gene-by-gene-based biosynthetic pathway of pepper capsianoside biosynthesis, including both core and decorative reactions. Given that one of these decorative pathways, namely the glycosylation of acyclic diterpenoid glycosides, contributes to plant resistance, these data provide new insights and breeding resources for pepper. They additionally provide a blueprint for the better understanding of the biosynthesis of species-specific natural compounds in general.

One of the most remarkable adaptations to survive attacks from predators is to detach an appendage-a process known as autotomy. This occurs in a variety of animals, including lizards (tail), crabs (legs), and starfish (arms). There has been extensive investigation of the evolution, ecology, and biomechanical impact of autotomy,^1,2,3 but little is known about neural mechanisms controlling autotomy in animals. However, evidence for the existence of a peptide that acts as an autotomy-promoting factor in starfish has been reported.⁴ While investigating in vivo effects of a sulfakinin/cholecystokinin-type neuropeptide (ArSK/CCK1) in the starfish Asterias rubens,^5,6 we observed that this peptide triggered arm autotomy in some animals. Furthermore, when injection of ArSK/CCK1 was combined with mechanical clamping of an arm, autotomy of the clamped arm occurred in 85% of animals tested, with 46% also autotomizing one or more other arms. In contrast, no autotomy was observed in clamped animals that were injected with water (control). To examine the physiological relevance of these findings, we analyzed expression of ArSK/CCK1 in the autotomy plane, a specialized region at the base of the arms in A. rubens.^7,8 In accordance with its in vivo effects, nerve fibers expressing ArSK/CCK1 were revealed in the tourniquet muscle, a band of muscle that mediates constriction of the arm during and after autotomy. We conclude that ArSK/CCK1 acts as an autotomy-promoting factor in starfish and as such it is the first neuropeptide to be identified as a regulator of autotomy in animals.

Recent work across species has shown that midbrain dopamine neurons signal not only errors in the prediction of reward value but also in the prediction of value-neutral sensory features. To support learning of associative structures in downstream areas, identity prediction errors (iPEs) should signal specific information about the mis-predicted outcome. Here, we used pattern-based analysis of functional magnetic resonance imaging (fMRI) data acquired during reversal learning to characterize the information content of iPE responses in the human midbrain. We find that fMRI responses to value-neutral identity errors contain information about the identity of the unexpectedly received reward (positive iPE+) but not about the identity of the omitted reward (negative iPE-). Exploratory analyses revealed representations of iPE- in the dorsomedial prefrontal cortex. These results demonstrate that ensemble midbrain responses to value-neutral identity errors convey information about the identity of unexpectedly received outcomes, which could shape the formation of novel stimulus-outcome associations that constitute cognitive maps.

Salinization poses an increasing problem worldwide, threatening freshwater organisms and raising questions about their ability to adapt. We explored the mechanisms enabling a planktonic crustacean to tolerate elevated salinity. By gradually raising water salinity in clonal cultures from 185 Daphnia magna populations, we showed that salt tolerance strongly correlates with native habitat salinity, indicating local adaptation. A genome-wide association study (GWAS) further revealed a major effect of the Alpha,alpha-trehalose-phosphate synthase (TPS) gene, suggesting that trehalose production facilitates salinity tolerance. Salinity-tolerant animals showed a positive correlation between water salinity and trehalose concentrations, while intolerant animals failed to produce trehalose. Animals with a non-functional TPS gene, generated through CRISPR-Cas9, supported the trehalose role in salinity stress. Our study highlights how a keystone freshwater animal adapts to salinity stress using an evolutionary mechanism known in bacteria, plants, and arthropods.

Expert face processes are refined and tuned through a protracted development. Exposure statistics of the daily visual experience of neurotypical adults (the face diet) show substantial exposure to familiar faces. People with autism spectrum disorder (ASD) do not show the same expertise with faces as their non-autistic counterparts. This may be due to an impoverished visual experience with faces, according to experiential models of autism. Here, we present the first empirical report on the day-to-day visual experience of the faces of adults with ASD. Our results, based on over 360 h of first-person perspective footage of daily exposure, show striking qualitative and quantitative differences in the ASD face diet compared with those of neurotypical observers, which is best characterized by a pattern of reduced and atypical exposure to familiar faces in ASD. Specifically, duration of exposure to familiar faces was lower in ASD, and faces were viewed from farther distances and from viewpoints that were biased toward profile pose. Our results provide strong evidence that individuals with ASD may not be getting the experience needed for the typical development of expert face processes.

Land plant bodies develop from stem cells located in meristems. However, we know little about how meristems initiate from non-meristematic cells. The haploid body of bryophytes develops from unicellular spores in isolation from the parental plant, which allows all stages of development to be observed. We discovered that the Marchantia spore undergoes a series of reproducibly oriented cell divisions to generate a flat prothallus on which a meristem later develops de novo. The young sporeling comprises an early cell mass. One cell of the early cell mass elongates and undergoes a formative division that produces the prothalloblast, which initiates prothallus formation. A symmetric division of the prothalloblast followed by two transverse divisions generates a four-celled plate that expands into a flat disc through oblique divisions in three of the four plate-cell-derived quadrants. One quadrant gives rise to a flat flabellum. A notch with a meristem and apical stem cell develops at the margin of the flabellum. The transcription factor Marchantia class III homeodomain-leucine-zipper (MpC3HDZ) is a marker of the first flat prothallus structure and polarizes to the dorsal tissues of flabella and meristems. Mpc3hdz mutants are defective in setting up dorsoventrality and thallus body flatness. We report how a regular set of cell divisions forms the prothallus-the first dorsoventral structure-and how cells on the margin of the prothallus develop a dorsoventralized meristem de novo.

Infants' thoughts are classically characterized as iconic, perceptual-like representations.^1,2,3 Less clear is whether preverbal infants also possess a propositional language of thought, where mental symbols are combined according to syntactic rules, very much like words in sentences.^{4,5,6,7,8,9,10,11,12,13,14,15,16,17} Because it is rich, productive, and abstract, a language of thought would provide a key to explaining impressive achievements in early infancy, from logical inference to representation of false beliefs.^{18,19,20,21,22,23,24,25,26,27,28,29,30,31} A propositional language-including a language of thought⁵-implies thematic roles that, in a sentence, indicate the relation between noun and verb phrases, defining who acts on whom; i.e., who is the agent and who is the patient.^{32,33,34,35,36,37,38,39} Agent and patient roles are abstract in that they generally apply to different situations: whether A kicks, helps, or kisses B, A is the agent and B is the patient. Do preverbal infants represent abstract agent and patient roles? We presented 7-month-olds (n = 143) with sequences of scenes where the posture or relative positioning of two individuals indicated that, across different interactions, A acted on B. Results from habituation (experiment 1) and pupillometry paradigms (experiments 2 and 3) demonstrated that infants showed surprise when roles eventually switched (B acted on A). Thus, while encoding social interactions, infants fill in an abstract relational structure that marks the roles of agent and patient and that can be accessed via different event scenes and properties of the event participants (body postures or positioning). This mental process implies a combinatorial capacity that lays the foundations for productivity and compositionality in language and cognition.

The catastrophic loss of aquatic life in the Central European Oder River in 2022, caused by a toxic bloom of the haptophyte microalga Prymnesium parvum (in a wide sense, s.l.), underscores the need to improve our understanding of the genomic basis of the toxin. Previous morphological, phylogenetic, and genomic studies have revealed cryptic diversity within P. parvum s.l. and uncovered three clade-specific (types A, B, and C) prymnesin toxins. Here, we used state-of-the-art long-read sequencing and assembled the first haplotype-resolved diploid genome of a P. parvum type B from the strain responsible for the Oder disaster. Comparative analyses with type A genomes uncovered a genome-size expansion driven by repetitive elements in type B. We also found conserved synteny but divergent evolution in several polyketide synthase (PKS) genes, which are known to underlie toxin production in combination with environmental cues. We identified an approximately 20-kbp deletion in the largest PKS gene of type B that we link to differences in the chemical structure of types A and B prymnesins. Flow cytometry and electron microscopy analyses confirmed diploidy in the Oder River strain and revealed differences to closely related strains in both ploidy and morphology. Our results provide unprecedented resolution of strain diversity in P. parvum s.l. and a better understanding of the genomic basis of toxin variability in haptophytes. The reference-quality genome will enable us to better understand changes in microbial diversity in the face of increasing environmental pressures and provides a basis for strain-level monitoring of invasive Prymnesium in the future.

Aaron O'Dea and Kimberly García-Méndez introduce the cupuladriids, a group of bryozoans that are atypical for their ability to actively move.

Europe's semi-natural grasslands support notably high levels of temperate biodiversity across multiple taxonomic groups. However, these ecosystems face unique conservation challenges. Contemporary agricultural practices have replaced historical traditional low-intensity agriculture in many regions, resulting in a spectrum of management intensities within these ecosystems, ranging from highly intensive methods to complete abandonment. Paradoxically, both extremes along this spectrum of management intensity can be detrimental to biodiversity of semi-natural grasslands. Moreover, while anthropogenic climate change is an overarching threat to these ecosystems, rapid changes in land use and its intensity often present more immediate pressures. Often occurring at a faster rate than climate change itself, these land-use changes have the potential to rapidly impact the biodiversity of these grasslands. Here, we divide the ecological processes, threats, and developments to semi-natural grasslands into three sections. First, we examine the different impacts of agricultural intensification and abandonment on these ecosystems, considering their different consequences for biodiversity. Second, we review seminal works on various evidence-based management practices and offer a concise summary that provides support for various conservation and management strategies. However, the socio-economic factors that drive both abandonment and intensification in semi-natural grasslands can also be used to develop solutions through strategic governmental and non-governmental interventions. Accordingly, we conclude with a way forward by providing several key policy recommendations. By synthesizing existing knowledge and identifying research gaps, this essay aims to provide valuable insights for advancing the sustainable management of semi-natural grasslands.