Abstract River damming alters hydrochorous conditions and induces habitat fragmentation, thereby impacting ecological processes in aquatic plants. However, the genetic connectivity and consequences of plant populations under such disturbances remain poorly characterized. In this study, we investigated the Three Gorges Dam’s (TGD) impacts through genetic analyses of 379 Phragmites australis individuals from 11 riparian populations along the Yangtze River, China, using microsatellite markers. Among three sections (upstream, midstream, and downstream), downstream populations exhibited the highest genetic diversity (He = 0.534). STRUCTURE analyses revealed two distinct genetic clusters corresponding to upstream and mid-downstream populations, with considerable genetic differentiation emerging between them. Although historically downward gene flow across the basin was significant (from upstream to midstream: m = 0.0030, 95% CI: 0.0018–0.0039; from upstream to downstream: m = 0.0036, 95% CI: 0.0023–0.0047), contemporary gene flow yielded mostly non-significant estimates, except for a pronounced dispersal signal from midstream to downstream groups (M = 0.0876, 95% CI: 0.0592–0.1160). This shift highlights TGD-mediated distinct consequences of recent genetic connectivity. Notably, downstream populations maintained substantial genetic diversity, likely sustained through persistent genetic connectivity with adjacent populations despite hydrological modifications. These findings elucidate the distinct impacts of large-scale dams on riparian plant genetics, propose prioritized conservation strategies for vulnerable upstream populations, and provide empirically grounded insights for biodiversity management in dam-regulated riverine landscapes.

Most mutualisms are parasitized by third-party species that inflict costs to the mutualists. How such parasites affect mechanisms that help maintain mutualism stability is poorly understood, even in well-studied systems. Angiosperm plants tend to invest most resources in tissue that yields high net benefits. In mutualisms with plant hosts, reduction in such investment can function as a key stability-promoting mechanism, such as in fig-wasp mutualisms. Here, uncooperative symbiont wasps that fail to pollinate incur "sanctions" via reduced host investment to unpollinated figs, realized via fig abortion, killing all wasp offspring, or via elevated offspring mortality within unaborted figs. We experimentally exposed host Ficus racemosa figs to parasitic wasps Sycophaga fusca, which convert fig flowers into offspring without benefitting host trees, with or without uncooperative (pollen-free) or cooperative (pollen-laden) symbiont pollinator wasps Ceratosolen fusciceps. Pollen-free C. fusciceps were still able to convert fig flower ovaries into wasp offspring, whereas those naturally pollen laden were prevented from reproducing by experimental manipulation. Independent of the effects of pollination and reproduction by pollinators, increased exposure to S. fusca parasites resulted in reduced rates of fig abortion and gall failure in unaborted figs. Although S. fusca convert flower ovaries that could otherwise become beneficial pollinator offspring or fig seeds into parasite offspring, figs with intermediate levels of parasite exposure received high levels of investment. Our results suggest that S. fusca parasite oviposition/larval activities can result in host trees boosting investment to figs, even when this may counter the tree's interests. We suggest that oviposition/larval activity by these parasites may mimic the biochemical pathways of pollinator gall formation and seed production.

Although genetic diversity and species diversity in a community often covary, the direction and strength of the covariation vary. However, this variation in the relationship of these two diversities is poorly understood. Here we investigated the role of host‐specific herbivores in generating species–genetic diversity relationship in plant communities. We quantified host specificity for Fagaceae plants–acorn weevil bipartite networks in a subtropical forest and modeled the effect of weevil herbivory on the relationship. The results showed a consistently negative relationship between Fagaceae species diversity and the genetic diversity of the dominant species, Lithocarpus glaber . Our analysis showed this negative relationship arose from a positive effect of weevil host‐specificity on Fagaceae plant richness on the one hand and the negative effect of weevil host‐specificity on the genetic diversity of L. glaber on the other hand. This latter negative effect was possibly due to differentiated selection of weevils on different genotypes of L. glaber . Our study highlights the importance of considering trophic interactions and herbivore host‐specificity in explaining the species–genetic diversity relationship.

Closely related and co-distributed species usually share a common phylogeographic history, but it remains unclear whether ecologically interacting species can respond synchronously to historical climate changes. Here, we focused on a fig-pollinator mutualism comprising Ficus pumila var. pumila and its obligate pollinators (morphospecies Wiebesia pumilae), and collected samples across most of their distribution ranges. We employed cytoplasmic DNA sequences and nuclear microsatellite loci to reveal the species composition within the pollinators and to test whether the two mutualists exhibited similar postglacial phylogeographic patterns. We identified three cryptic pollinator species, with two dominant cryptic species exhibiting parapatric distributions in the northern and southern parts of the plant's range, respectively. Similar current spatial genetic structures were detected in the two dominant cryptic pollinator species and the host plant, with both showing eastern and western genetic clusters. Moreover, evidence for postglacial expansion was found for all three species, and their potential refugia during the Last Glacial Maximum were located in the eastern and western parts of their distribution ranges. These results suggest synchronous responses to historical climate changes. Our study demonstrates congruent phylogeographic patterns between obligate mutualists and highlights the role of biogeographic factors in shaping the current biodiversity across trophic levels. (sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(Ficus pumila var. pumila)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic):(sic)(sic)(sic)(sic)(sic)(sic)Wiebesia pumilae)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)DNA(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)3(sic)(sic)(sic)(sic),(sic)(sic)2(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)2(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic),(sic)2(sic)(sic)(sic)(sic)(sic).(sic)(sic),(sic)(sic)(sic)(sic)2(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

Asian rainforests are a biodiversity hotspot and are dominated by dipterocarps. Thus, protecting endangered dipterocarp species living on the distribution boundary of dipterocarps is a central factor in maintaining the range of Asian rainforests. Despite the perceived conservation priority of these species, we know little about how they became endangered and how they have adapted to marginal habitats. Here, we focused on the population genomics of Hopea chinensis, an endangered species narrowly distributed at the northern limit of dipterocarps, to (1) reveal its demographic history and infer factors contributing to endangered status; (2) evaluate the genetic consequences of its small remnant population; and (3) identify key genes associated with its adaptation. We found drastic population declines after the Last Glacial Maximum, suggesting the role of human disturbances in the endangered status. Despite high levels of inbreeding, we detected only 441 derived deleterious and 337 derived major-effect mutations, which were not significantly enriched in any KEGG pathway, providing evidence of low genetic loads. Furthermore, selective sweep analysis showed 12 genes associated with cold and drought tolerance and plant defense and immunity. Comparative genomics identified 125 specific and 30 lost gene families in the genome of H. chinensis, many of which were relevant to the responses to biotic and abiotic stresses. Our findings, therefore, reveal the genomic characteristics linked with the endangered status and adaptations for H. chinensis. Together with the population genomic results from two other dipterocarp species, we highlighted the necessity to establish nature reserves to prevent further human disturbances and to comprehensively describe the mutualistic and antagonistic networks associated with endangered dipterocarp species to guide in-situ and ex-situ conservation.

Some fig species introduced outside of their native range have become invasive when colonized by their obligate pollinating wasps, but how these pollinators migrated and adapted to novel environments are less studied. Here, we focus on Eupristina verticillata, the obligate pollinating wasp of an invasive fig tree species (Ficus microcarpa), to uncover its demography and the molecular basis for adaptations to novel environments. We find that only one of the three cryptic species colonized in the sampling locations outside of its native range. This dominant cryptic species migrated simultaneously from the native range to the Americas and to the Mediterranean c. 130 years ago. Moreover, selective sweep analyses reveal several positively selected genes associated with adaptations to the nonnative range. Genome-wide association detect a nonsynonymous substitution in a dopamine N-acetyltransferase gene significantly linked with brood size. Our study outlines the route to colonization and genetic adaptations of an invasive mutualism.

G-quadruplexes play a crucial role in transcription, translation, and DNA replication in plant genomes. Here, we comprehensively examined the prevalence and functions of G-quadruplexes in Vitis vinifera. A total of 467,813 G-quadruplexes were identified in grapevine genome, with enrichment in the promoter (0.54/kbp) and near transcription start sites (TSSs, 1.00/kbp), and showed conservative strand preference. The G-quadruplex density in centromeres exhibited heterogeneity. The differentially expressed genes (DEGs) under two-day drought stress manifested high G-quadruplex density in the promoter and TSS regions. The upregulated DEGs showed template strand-biased G-quadruplex enrichment, while downregulated DEGs displayed coding strand dominance linked to metal ion homeostasis and sugar–acid metabolism pathways, respectively. G-quadruplexes were enriched in key sugar–acid metabolism genes, including pyruvate kinase and sucrose synthase. The number of G-quadruplexes in sucrose transferase VINV genes was higher than that in the CWINV and NINV genes. This study revealed G-quadruplexes as regulatory elements of stress response and berry development, providing abundant genetic targets for precision breeding and the quality improvement of grapevines.

Pleistocene climatic oscillations caused periodic decline and rise of sea levels, leading to dispersion and retraction cycles of island flora. Yet, the role of island refugia in the current Sino-Japanese Floristic Region remains poorly understood. In this study, we investigated the population genetic structure of the widespread Sino-Japanese Floristic Region tree Machilus thunbergii to infer the potential impact of island refugia. We collected 1378 samples from 64 locations across the distribution ranges. Using chloroplast DNA and microsatellite markers, we found a pronounced genetic differentiation between mainland and island populations, which can be divided further into two and three groups, respectively. Furthermore, comparable numbers of private alleles and haplotypes are present in both mainland and island populations. No essential current gene flow was detected between mainland and island populations after their separation 14 000 years ago. Such patterns are hypothesized to result from the influence of multiple glacial island refugia during Pleistocene climatic oscillations, with limited pollen and seed dispersal of the species. Our findings underscore that the islands and submerged land bridge can act as refugia for plants during glacial periods and have essentially shaped the genetic structure of M. thunbergii populations.

Dipterocarpoideae species form the emergent layer of Asian rainforests. They are the indicator species for Asian rainforest distribution, but they are severely threatened. Here, to understand their adaptation and population decline, we assemble high-quality genomes of seven Dipterocarpoideae species including two autotetraploid species. We estimate the divergence time between Dipterocarpoideae and Malvaceae and within Dipterocarpoideae to be 108.2 (97.8‒118.2) and 88.4 (77.7‒102.9) million years ago, and we identify a whole genome duplication event preceding dipterocarp lineage diversification. We find several genes that showed a signature of selection, likely associated with the adaptation to Asian rainforests. By resequencing of two endangered species, we detect an expansion of effective population size after the last glacial period and a recent sharp decline coinciding with the history of local human activities. Our findings contribute to understanding the diversification and adaptation of dipterocarps and highlight anthropogenic disturbances as a major factor in their endangered status.

Plant-parasitic nematodes (PPNs) are among the most damaging pathogens to host plants. Plants can modulate their associated bacteria to cope with nematode infections. The tritrophic plant–nematode–microbe interactions are highly taxa-dependent, resulting in the effectiveness of nematode agents being variable among different host plants. Ficus tikoua is a versatile plant with high application potential for fruits or medicines. In recent years, a few farmers have attempted to cultivate this species in Sichuan, China, where parasitic nematodes are present. We used 16S rRNA genes to explore the effects of nematode parasitism on root-associated bacteria in this species. Our results revealed that nematode infection had effects on both endophytic bacterial communities and rhizosphere communities in F. tikoua roots, but on different levels. The species richness increased in the rhizosphere bacterial communities of infected individuals, but the community composition remained similar as compared with that of healthy individuals. Nematode infection induces a deterministic assembly process in the endophytic bacterial communities of parasitized organs. Significant taxonomic and functional changes were observed in the endophytic communities of root knots. These changes were characterized by the enrichment of nitrogen-fixing bacteria, including Bradyrhizobium, Allorhizobium–Neorhizobium–Pararhizobium–Rhizobium, and nematode-antagonistic bacteria, such as Pseudonocardia, Pseudomonas, Steroidobacter, Rhizobacter, and Ferrovibrio. Our results would help the understanding of the tritrophic plant–nematode–bacterium interactions in host plants other than dominant crops and vegetables and would provide essential information for successful nematode management when F. tikoua were cultivated on large scales.

Chemical communication is critical in establishing angiosperm–pollinator mutualisms. However, our understanding of how chemical communication shapes coevolution remains limited. Here, we integrated information theory to model three coevolutionary scenarios (I‒III), where the pollinator fitness is always optimized by the highest certainty of chemical information provided by plants, but plant fitness is determined by (I) the certainty of chemical information attracting pollinators, (II) the uncertainty of chemical information confusing antagonists, or (III) both aspects. We found that the statistical properties of empirical plant volatiles from 45 pairs of fig–pollinator mutualisms were best explained by the selection from both pollinators and antagonists (scenario III). Under this scenario, plant–pollinator mutualisms evolve to be specialized and as few as two volatile chemicals could supply sufficient information for pollinators’ host identification. Our study provides new insights into plant–pollinator coevolution and will facilitate further studies on the evolution and diversification in specialized plant–pollinator–herbivore systems.

Restoring vegetation in degraded ecosystems is an increasingly common practice for promoting biodiversity and ecological function, but successful implementation is hampered by an incomplete understanding of the processes that limit restoration success. By synthesizing terrestrial and aquatic studies globally (2594 experimental tests from 610 articles), we reveal substantial herbivore control of vegetation under restoration. Herbivores at restoration sites reduced vegetation abundance more strongly (by 89%, on average) than those at relatively undegraded sites and suppressed, rather than fostered, plant diversity. These effects were particularly pronounced in regions with higher temperatures and lower precipitation. Excluding targeted herbivores temporarily or introducing their predators improved restoration by magnitudes similar to or greater than those achieved by managing plant competition or facilitation. Thus, managing herbivory is a promising strategy for enhancing vegetation restoration efforts.

Landscape changes by anthropologic activities such as damming threaten local biodiversity through deforestation and subsequent geographic isolation. Ecological restoration through planting pioneer species could buffer the negative effects of landscape changes. As genetic variation of a species is important for its long-term persistence in the face of land use change, the temporal genetic variation of a pioneer plant species must be evaluated. Yet, it has received little attention. In this study, we used nuclear microsatellites to study the genetic variation of a wind-pollinated and wind-dispersed pioneer tree Pinus massoniana (Pinaceae) on islands in the Thousand-island Lake (TIL) formed by damming in 1959. Overall, high genetic diversity was observed in all individuals ( H E = 0.692), which is positively related to island size and independent of geographic isolation. Additionally, similar genetic diversity and differentiation was observed between old (within 5 generations after damming) and young cohorts (around 5–10 generations after damming). These results imply that P. massoniana did not lose genetic variation after the formation of the TIL. Furthermore, smaller variance in genetic differentiation that is dependent on geographic distance was found in the young cohort suggesting gene flow was maintained in the face of geographic isolation after damming. Overall, our findings revealed that pioneer wind-pollinated and wind-dispersed plant species are resistant to the negative effects of damming, and they could be used to restore disturbed habitats caused by anthropogenic landscape changes.

榕属植物与其传粉小蜂组成了高度专一的专性共生关系(榕-蜂共生系统),如此高度紧密的互作关系被认为是驱动两者多样化的关键因素.榕-蜂共生系统主要依靠化学通讯完成相互识别,但目前仍不清楚化学通讯是如何维系现有共生关系并促进物种形成的.结合已有研究,系统梳理了榕-蜂共生系统化学通讯的基础与两者特异性识别的机制,阐述化学通讯在物种和种群层次对维持这一专性传粉关系的重要贡献,进而探讨化学通讯如何在协同成种和宿主转移成种两种模式中介导物种形成.最后,结合生理与多组学等技术展望榕-蜂共生系统的未来研究方向,为深入解析植物与昆虫协同进化的机制以及全球变化下物种的潜在响应模式提供重要参考.

IntroductionPlants that display heteroblasty possess conspicuous variations in leaf morphology between their juvenile and adult phases, with certain species retaining juvenile-like leaves even in adulthood. Nevertheless, the ecological advantages of maintaining two or more distinct leaf types in heteroblastic plants at the adult stage remain unclear.MethodThe aim of this study is to examine the adaptive significance of heteroblastic leaves sampled from branches with divergent functions (sterile and fertile branches) of mature Ficus pumila individuals by comparing their morphological, anatomical, and physiological characteristics.ResultLeaves on sterile branches (LSs) exhibited a significantly larger specific leaf area, thinner palisade and spongy tissues, lower chlorophyll contents, and lower light saturation points than leaves on fertile branches (LFs). These results demonstrate that LSs are better adapted to low light environments, while LFs are well equipped to take advantages of high light conditions. However, both LFs and LSs have a low light compensation point with no significant difference between them, indicating that they start to accumulate photosynthetic products under similar light conditions. Interestingly, significant higher net photosynthetic rate was detected in LFs, showing they have higher photosynthetic capacity. Furthermore, LFs produced significant more nutrients compared to LSs, which may associate to their ability of accumulating more photosynthetic products under full light conditions and higher photosynthetic capacity.DiscussionOverall, we observed a pattern of divergence in morphological features of leaves on two functional branches. Anatomical and physiological features indicate that LFs have an advantage in varied light conditions, providing amounts of photosynthetic products to support the sexual reproduction, while LSs adapt to low light environments. Our findings provide evidence that heteroblasty facilitates F. pumila to utilize varying light environments, likely associated with its growth form as a climbing plant. This strategy allows the plant to allocate resources more effectively and optimize its overall fitness.

Identifying conservation units is crucial for the effective conservation of threatened species. Previous cases are almost exclusively based on large-scale but coarse sampling for genetic structure analyses. Significant genetic structure can occur within a small range, and thus multiple conservation units may exist in narrowly distributed plants. However, small-scale genetic structure is often overlooked in conservation planning especially for wind-pollinated and wind-dispersed trees, largely due to the absence of dense and elaborate sampling. In this study, we focused on a representative endangered relict plant, Metasequoia glyptostroboides. Using both nuclear microsatellites (nSSRs) and chloroplast DNA (cpDNA) fragments, we sampled across the narrow distribution range of this species and determined its conservation units by exploring its genetic structure and historical demography. cpDNA haplotypes were classified into two groups, but mixed in space, suggesting that the existent wild trees of M. glyptostroboides cannot be divided into different evolutionarily significant units. However, using nSSRs, we detected strong spatial genetic structure, with significant genetic differentiation and weak gene flow between the samples in the east of the species' distribution range and other samples. The divergence between the two nSSR groups was dated to the Last Glacial Maximum (c. 19.6 kya), suggesting that such spatial genetic structure has been maintained for a long term. Therefore, these two nSSR groups should be considered as different conservation units, that is, management units, to protect intergroup genetic variations, which is likely to be the outputs of local adaptation. Our findings highlight the necessity to reveal small-scale genetic structure and population demography to improve the conservation strategies of evolutionary potential of endangered plants.

The mechanisms of chemoreception in fig wasps (Hymenoptera, Agaonidae) are of primary importance in their co-evolutionary relationship with the fig trees they pollinate. We used transcriptome sequences of 25 fig wasps in six genera that allowed a comparative approach to the evolution of key molecular components of fig wasp chemoreception: their odorant (OR) and gustatory (GR) receptor genes. In total, we identified 311 ORs and 47 GRs, with each species recording from 5 to 30 OR genes and 1-4 GR genes. 304 OR genes clustered into 18 orthologous groups known to be sensitive to cuticular hydrocarbons (CHC), pheromones, acids, alcohols and a variety of floral scents such as cineole, Linalool, and Heptanone. 45 GR genes clustered into 4 orthologous groups that contain sweet, bitter, CO2 and undocumented receptors. Gene sequences in most orthologous groups varied greatly among species, except for ORco (60.0% conserved) and sweet receptors (30.7% conserved). Strong purifying selection of both odorant and gustatory genes was detected, as shown by low ω values. Signatures of positive selection were detected in loci from both OR and GR orthologous groups. Fig wasps have relatively few olfactory and especially gustatory receptors, reflecting the natural history of the system. Amino acid sequences nonetheless vary significantly between species and are consistent with the phylogenetic relationships among fig wasps. The differences in ORs within some orthologous groups from the same species, but different hosts and from closely related species from one host can reach as low as 49.3% and 9.8% respectively, implying the ORs of fig wasps can evolve rapidly to novel ecological environments. Our results provide a starting point for understanding the molecular basis of the chemosensory systems of fig wasps.

Secondary seed dispersal is one of the most important factors contributing to the co-existence of plant species. Variations in fruit properties including fruit size, physical defense and chemical composition are considered to influence seed foraging and secondary dispersal, but the details remain unclear. Here, we focused on three common nut-bearing tree species (Quercus aliena Blume, Quercus dentata Thunb., and Quercus variabilis Blume), which often co-occur in mixed deciduous forest in northern China. We estimated their acorn properties and evaluated their effects on the secondary dispersal patterns. We found similar chemical profiles but different acorn sizes and physical defense among these three species. Moreover, we detected distinct secondary dispersal strategies in relation to their acorn properties: Q. dentata produced the smallest-sized acorns with the lowest physical defense, which had the shortest dispersal range but the highest survival rate; Q. variabilis generating the largest-sized acorns with the highest physical defense, which suffered the lowest survival rate but benefited from the longest dispersal range; and an intermediate strategy existed in Q. aliena. In addition, squirrels and rats were the secondary seed dispersal agents, but rats were the more effective seed disperser. Our results therefore revealed that differentiations in acorn properties have derived distinct trade-offs in secondary seed dispersal strategies, likely facilitating the coexistence of the three studied species. Our study addresses the necessity to examining the fruit properties in biotic interactions which promote coexistence.

Background Rabbits are well-domesticated animals. As a crucial economic animal, rabbit has been successfully bred into wool-use, meat-use and fur-use breeds. Hair length is one of the most economically important traits affecting profitability in wool rabbits. In this study, to identify selection signatures with the long-hair trait, whole-genomic resequencing of long-haired rabbits (Angora rabbits) and short-haired rabbits (Rex and New Zealand rabbits) was performed. Results By genome-wide selective sweeping analysis based on population comparison, we identified a total of 5.85 Mb regions (containing 174 candidate genes) with strong selection signals. Six of these genes ( Dusp1 , Ihh , Fam134a , Map3k1 , Spata16 , and Fgf5 ) were enriched in the MAPK signalling and Hedgehog signalling pathways, both of which are closely associated with hair growth regulation. Among these genes, Fgf5 encodes the FGF5 protein, which is a well-established regulator of hair growth. There was a nonsynonymous nucleotide substitution (T19234C) in the Fgf5 gene. At this locus, the C allele was present in all of the tested Angora rabbits, while the T allele was dominant in New Zealand and Rex rabbits. We further confirmed that the C allele was conserved in Angora rabbits by screening an additional 135 rabbits. Moreover, the results of functional predictions and co-immunoprecipitation revealed that the T19234C mutation impaired the binding capacity of FGF5 to its receptor FGFR1. Conclusions We discovered that the homozygous missense mutation T19234C within Fgf5 might contribute to the long-hair trait of Angora rabbits by reducing its receptor binding capacity. This finding will provide new insights into the genetic basis underlying the genetic improvement of Angora rabbits and benefit the improvement of rabbit breeding in the future.

Background: Although colorectal cancer (CRC) screening reduces both CRC incidence and CRC-related mortality, it is underutilized, especially among those with lower socioeconomic status (SES) and in racial and ethnic minoritized populations who have been disproportionately impacted by COVID-19. The shift in healthcare priorities to contain and mitigate COVID-19 over the last few years reduced clinical capacity for non-urgent care, including CRC screening. This study aimed to assess the impact of COVID-19 on disparities in CRC screening. Methods: Blue Cross Blue Shield (BCBS) insures approximately one third of Americans. We leveraged BCBS Axis data to examine temporal patterns in CRC screening among individuals aged 45-75 years during 2017-2021, focusing on three periods: 1) first wave of COVID-19 outbreak (Mar-Apr 2020); 2) second wave of COVID-19 outbreak (i.e., the Delta variant, Jan-Feb 2021); and 3) the most recent 2-month interval for which data are available (Nov-Dec 2021). Both invasive and non-invasive CRC screening procedures were identified, and beneficiaries who received screening one year before were excluded. Screening rates within each 2-month interval were calculated. Neighborhood SES was assessed by Social Deprivation Index at the zip code level and categorized into quintiles. Results: The study cohort included 27,628,570 individuals. Throughout the 5-year period, except for the 1st wave of COVID-19 outbreak, screening rates were higher in areas with higher SES. Prior to the pandemic (Jan 2017–Feb 2020), the average bimonthly screening rate in areas with the highest SES was 2.1%, compared to 1.7% in areas with the lowest SES (p <0.001). During the 1st wave of COVID-19 outbreak, screening rate decreased to approximately 0.8% across all SES quintiles. During the 2nd wave of COVID-19 outbreak, screening rates were 1.7% and 1.3% in the highest and lowest SES areas, respectively. For the last 2-month interval in our study period (Nov-Dec 2021), screening rates increased to 2.4% and 1.8% in areas with the highest and lowest SES, respectively. Among 9,565,516 beneficiaries with known race and ethnicity, 8.0%, 11.0%, 3.3% and 0.4% were non-Hispanic Black, Hispanic/Latino, Asian, and Native Americans/Pacific Islanders, respectively. Across all racial and ethnic groups, the average bimonthly screening rate was 1.9% prior to the pandemic, 0.7% in Mar-Apr 2020, 1.5% in Jan-Feb 2021, and 2.1% in Nov-Dec 2021. Conclusion: After the onset of COVID-19, CRC screening rate decreased broadly and reached a similar level in all SES groups in early 2020, but it then recovered at a different pace for individuals with different SES, maintaining and even exacerbating inequities that existed prior to the pandemic. Screening patterns were comparable across different racial and ethnic groups who were privately insured through BCBS. Findings from this very large study may help inform interventions to address social and structural determinants of health and reduce the disproportionate burden of CRC in individuals residing in socially deprived areas. Citation Format: Arfan Siddique, Rong Wang, Jacquelyne Gaddy, Cary Gross, Xiaomei Ma. Impact of COVID-19 on colorectal cancer screening disparities: Results from a large commercially insured population in the United States [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C129.