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BACKGROUND: Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood. RESULTS: In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence. CONCLUSIONS: These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.

Asexual eukaryotes tend to occupy broader geographical ranges than their sexually reproducing relatives, with this phenomenon seemingly linked to ecological differentiation among closely related asexual and sexual lineages. Here, we used sympatric asexual and sexual Corbicula lineages to assess their ecological niche divergence and genetic differentiation within East and Southeast Asia. The predicted suitable area for asexual lineages was concentrated to Southern China, South Korea, Japan and a small region in Thailand and Vietnam, while that for sexual lineages mainly covered the middle and lower reaches of the Yangtze River in China, Japan, Malaysia, Philippines as well as Indonesia. Potential sympatric distribution of both lineages was found in the Yangtze River Basin in China, the Central and Southern Japan. Anthropogenic activity was an important variable for the distribution of asexual lineages, while precipitation variables underpinned that of sexual lineages. Although both lineages had distinct distribution patterns, the identity and similarity tests overall indicated that the asexual and sexual lineages had similar niche. Genetic analyses suggested that 348 COI sequences from 47 populations were separated into two major clusters; one consisted of sexual lineages, and the other comprised asexual lineages across all studied regions and minor sexual lineages from China. The present study suggests that sexual and asexual Corbicula lineages have similar ecological niches accompanying COI genetic differentiations in East and Southeast Asia. [ABSTRACT FROM AUTHOR]

Asexuality is a sexual orientation centered around low or absent sexual attraction. Despite the growth of empirical scholarship on asexuality, laboratory sex research with asexual individuals remains significantly underutilized. As such, we conducted a qualitative survey aimed at examining asexual individuals’ perceptions of laboratory sex research as well as their perspectives/experiences on participation. Reflexive thematic analysis of 412 responses revealed 4 themes and 10 sub-themes focused on mapping the domain of asexuality, participants’ trust, distrust and ambivalence toward laboratory sex research, and developing best practices for overcoming challenges with asexual individuals. A large proportion of asexual individuals emphasized concerns related to the potential medicalization and pathologization of asexuality, with 34.6% exhibiting their unwillingness to participate. Nonetheless, 41.7% of asexual individuals expressed a desire to take part in laboratory sexuality studies. These findings indicate a strong interest in laboratory sex research, driven by the lack of knowledge about ace sexual functioning. To further improve ace individuals´ engagement and experience in such studies, a set of participant-driven recommendations was presented. As such, this study highlights the importance of grounding future laboratory sex research with asexual individuals in ethical and reliable procedures. [ABSTRACT FROM AUTHOR]

The Salix genus of the Salicaceae family has advantages such as rapid initial growth, a high germination rate, and asexual reproduction; therefore, it is used as a short-rotation energy crop for biomass production. The National Institute of Forest Science created new interspecific hybrid cultivars with superior biomass production by artificially interbreeding Salix caprea L. and Salix gracilistyla Miq. Identifying these hybrids during the seedling stage is challenging because their separate reproductive and vegetative growth stages necessitate prolonged observation of their morphological characteristics. Consequently, a reliable identification method is required to overcome these limitations. This study aimed to develop nuclear DNA markers to distinguish between S. caprea, S. gracilistyla, and their interspecific hybrids. An evaluation of 35 nuclear simple-sequence repeat (nSSR) markers in the Salix genus revealed two markers that distinguish these parent species and their hybrids. A sequence analysis confirmed the presence of insertion-deletion (InDel) regions within the nSSR markers that differed between S. caprea and S. gracilistyla. To effectively identify hybrids, a primer set comprising the InDel region, which exhibited only interspecies differences and no intraspecies differences, was developed. The results of this study will facilitate the genetic resource management of interspecific hybrids between S. caprea and S. gracilistyla, thus allowing for early identification and improved management of hybrids. [ABSTRACT FROM AUTHOR]

The floating freshwater fern Azolla is the only plant that retains an endocyanobiont, Nostoc azollae (aka Anabaena azollae), during its sexual and asexual reproduction. The increased interest in Azolla as a potential source of food and its unique evolutionary history have raised questions about its cyanotoxin content and genome. Cyanotoxins are potent toxins synthesized by cyanobacteria which have an anti-herbivore effect but have also been linked to neurodegenerative disorders including Alzheimer's and Parkinson's diseases, liver and kidney failure, muscle paralysis, and other severe health issues. In this study, we investigated 48 accessions of Azolla–Nostoc symbiosis for the presence of genes coding microcystin, nodularin, cylindrospermopsin and saxitoxin, and BLAST analysis for anatoxin-a. We also investigated the presence of the neurotoxin β-N-methylamino-L-alanine (BMAA) in Azolla and N. azollae through LC-MS/MS. The PCR amplification of saxitoxin, cylindrospermospin, microcystin, and nodularin genes showed that Azolla and its cyanobiont N. azollae do not have the genes to synthesize these cyanotoxins. Additionally, the matching of the anatoxin-a gene to the sequenced N. azollae genome does not indicate the presence of the anatoxin-a gene. The LC-MS/MS analysis showed that BMAA and its isomers AEG and DAB are absent from Azolla and Nostoc azollae. Azolla therefore has the potential to safely feed millions of people due to its rapid growth while free-floating on shallow fresh water without the need for nitrogen fertilizers. [ABSTRACT FROM AUTHOR]

In the face of escalating threats posed by human-induced climate change, urgent attention to coral reef restoration is imperative due to ongoing reef degradation. Here, we explored the potential of generating coral micropropagates as a tool to rapidly generate coral tissue for reef restoration and reef engineering. We developed a hypersalinity-induced polyp bailout protocol and a simple attachment device to support the growth of micropropagates on commonly used restoration substrates. We found that hypersalinity induction, at a rate of < 1 ppt hr-1, produced healthy micropropagates of the coral Stylophora pistillata. The highest attachment success (-74%) was achieved in CaCO3 substrate devices, which outperformed PVC (-48%) and Portland cement (-5%). Settled micropropagates displayed rapid growth rates on both CaCO3 (0.037 mm²/day ± 0.002 SE) and PVC (0.057 mm²/ day ± 0.008 SE) substrates, while Portland cement induced tissue degradation. Our study provides a detailed methodology for reliably generating, attaching, and growing coral micropropagates and underscores the potential of polyp bailout as a viable technique supporting coral propagation efforts. [ABSTRACT FROM AUTHOR]

Jellyfish blooms are increasingly prevalent coastal phenomena, with Aurelia coerulea being a significant contributor. The complex life history of jellyfish, featuring a sessile polyp stage, is a key factor in bloom formation, yet it is challenging to study in the field. This study aimed to describe the asexual reproduction of A. coerulea polyps in Jiaozhou Bay, China, and to assess their ability to form sedentary colonies and their relationship with environmental factors. Using settling plates, we observed polyps in situ and documented three asexual reproduction modes: budding, strobilation, and podocyst formation. Environmental parameters including temperature, salinity, dissolved oxygen (DO), chlorophyll a (Chl a), and the biomass of phytoplankton and zooplankton were monitored. Budding was the predominant reproductive method, featuring stolon budding in autumn and direct budding during the winter and spring seasons. Strobilation took place in the colder months, releasing ephyrae between April and May. Polyp abundance was positively correlated with seawater temperature and negatively correlated with DO concentration. Polyps at 1.0 m depth showed higher survivorship and proliferation over 8 months, whereas those at 2.0 m depth experienced a steady decline and died within 4 months. The study enhances our understanding of the life cycle and asexual reproduction strategies of A. coerulea polyps in the field, with implications for predicting and managing jellyfish blooms. The findings underscore the importance of temperature and DO in polyp survival and suggest that initial polyp population proliferation is crucial for long-term survival. [ABSTRACT FROM AUTHOR]

This qualitative study explores the stressful experiences faced by asexual individuals in South Korea. We conducted in-depth interviews with 12 South Korean adults who identified as asexual and analysed their data using consensus qualitative research. The analyses revealed 20 categories across five domains, including difficulties in defining and articulating asexual identity due to a lack of language and representation, facing denial and invalidation, navigating ambivalent experiences of invisibility, combating misconceptions, and encountering difficulties in connecting with asexual individuals and other members of the queer community. The study identified several stressors reported by South Korean asexual individuals, such as the dearth of language and representation regarding asexuality, lack of access to asexual networks, misconception that experiencing little or no sexual attraction is caused by a lack of love, casual use of the term ‘asexual’, and fear of increasing invisibility by concealing one’s asexual identity. Although these stressors have not been widely documented in other contexts, further research is needed to determine whether they are unique to the South Korean context. These findings highlight the need for greater awareness and understanding of asexuality in South Korea to promote the well-being and inclusion of asexual individuals. [ABSTRACT FROM AUTHOR]

Key message: The strong clonal growth of black locust (Robinia pseudoacacia L.) not only influences the stand structure of natural or artificially established stands, but also the genetic composition of seed harvested from such clonal stands. For the commercial production of genetically diverse seeds, the stand structure should be taken into account or, at best, seeds harvested from seed orchards should be used. Context: Black locust is characterised by intensive asexual reproduction through the formation of root suckers. By this means clonal structures can develop within black locust stands, in which ramets of a single clone can dominate extensive areas. Aims: We want to analyse to what extent clonal structures within black locust stands negatively influence the genetic composition and diversity in seed harvested in such stands. We discuss how a potential reduction in genetic diversity can be reduced by measures taken during harvesting and whether the harvesting of seed orchards may be a better alternative. Methods: We compare the genetic composition and diversity of parent trees and seed harvested from a clonal black locust stand with a seed orchard in which multiple ramets of selected clones were arranged in a randomised design. Results: Within the clonal stand, parent contributions to the seed lot analysed proved to be strongly uneven. Selfing rates were high and large full-sib families dominated within the seed lot. Although the relatively strong pollination from unknown pollen donors, probably located outside of the stand, prevented a massive loss of alleles, high selfing rates and the formation of large full-sib families led to an unequal distribution of alleles within the progeny. Within the seed orchard—even though it had a lower number of clones than expected—the randomised design promoted a more diverse pollination pattern. Conclusion: We conclude that for black locust, seed orchards have the greater potential to ensure a balanced genetic composition of harvested seed lots. If economic considerations make it necessary to harvest seed stands, this should only be done in a considered manner and, if possible, with knowledge of the clonal structures of the stand. [ABSTRACT FROM AUTHOR]

Background: Arbuscular mycorrhizal fungi (AMF) form mutualistic partnerships with approximately 80% of plant species. AMF, and their diversity, play a fundamental role in plant growth, driving plant diversity, and global carbon cycles. Knowing whether AMF are sexual or asexual has fundamental consequences for how they can be used in agricultural applications. Evidence for and against sexuality in the model AMF, Rhizophagus irregularis, has been proposed. The discovery of a putative mating-type locus (MAT locus) in R. irregularis, and the previously suggested recombination among nuclei of a dikaryon R. irregularis isolate, potentially suggested sexuality. Unless undergoing frequent sexual reproduction, evolution of MAT-locus diversity is expected to be very low. Additionally, in sexual species, MAT-locus evolution is decoupled from the evolution of arbitrary genome-wide loci. Results: We studied MAT-locus diversity of R. irregularis. This was then compared to diversification in a phosphate transporter gene (PTG), that is not involved in sex, and to genome-wide divergence, defined by 47,378 single nucleotide polymorphisms. Strikingly, we found unexpectedly high MAT-locus diversity indicating that either it is not involved in sex, or that AMF are highly active in sex. However, a strongly congruent evolutionary history of the MAT-locus, PTG and genome-wide arbitrary loci allows us to reject both the hypothesis that the MAT-locus is involved in mating and that the R. irregularis lineage is sexual. Conclusion: Our finding shapes the approach to developing more effective AMF strains and is highly informative as it suggests that introduced strains applied in agriculture will not exchange DNA with native populations. [ABSTRACT FROM AUTHOR]

Aim Location Method Results Conclusions The Hemiptera is the fifth‐largest insect order but among non‐native insect species is approximately tied with the Coleoptera as the most species‐rich insect order (Hemiptera comprise 20% more species than in world fauna). This over‐representation may result from high propagule pressure or from high species invasiveness. Here, we assess the reasons for over‐representation in this group by analysing geographical, temporal and taxonomic variation in numbers of historical invasions.Global.We assembled lists of historical Hemiptera invasions in 12 world regions, countries or islands (Australia, Chile, Europe, New Zealand, North America, South Africa, South Korea, Japan and the Galapagos, Hawaiian, Okinawa and Ogasawara Islands) and border interception data from nine countries (Australia, Canada, European Union, United Kingdom, Hawaii, Japan, New Zealand, South Korea, USA mainland and South Africa). Using these data, we identified hemipteran superfamilies that are historically over‐represented among established non‐native species, and superfamilies that are over‐represented among arrivals (proxied by interceptions). We also compared temporal patterns of establishments among hemipteran suborders and among regions.Across all regions, patterns of over‐ and under‐representation were similar. The Aphidoidea, Coccoidea, Aleyrodoidea, Cimicoidea and Phylloxeroida were over‐represented among non‐native species. These same superfamilies were not consistently over‐represented among intercepted species indicating that propagule pressure does not completely explain the tendency of some Hemiptera to be over‐represented among invasions. Asexual reproduction is common in most over‐represented superfamilies and this trait may be key to explaining high invasion success in these superfamilies.We conclude that both propagule pressure and species invasiveness are drivers of high invasion success in the Sternorrhyncha suborder (aphids, scales, whiteflies) and this group plays a major role in the exceptional invasion success of Hemiptera in general. The high historical rates of invasion by Sternorrhyncha species provide justification for biosecurity measure focusing on exclusion of this group. [ABSTRACT FROM AUTHOR]

Introduction: Reproductive isolation and hybrid sterility are mechanisms that maintain the genetic integrity of species and prevent the introgression of heterospecific genes. However, crosses of closely related species can lead to complex evolution, such as the formation of all-female lineages that reproduce clonally. Bighead catfish (Clarias macrocephalus) and North African catfish (C. gariepinus) diverged 40 million years ago. They are cultivated and hybridized in Thailand for human consumption. Male hybrids are sterile due to genome-wide chromosome asynapsis during meiosis. Although female hybrids are sometimes fertile, their chromosome configuration during meiosis has not yet been studied. Methods: We analyzed meiosis in the hybrid female catfish at pachytene (synaptonemal complexes) and diplotene (lampbrush chromosomes), using immunostaining to detect chromosome pairing and double-stranded break formation, and FISH with species-specific satellite DNAs to distinguish the parental chromosomes. Results: More than 95% of oocytes exhibited chromosome asynapsis in female hybrid catfish; however, they were able to progress to the diplotene stage and form mature eggs. The remaining oocytes underwent premeiotic endoreplication, followed by synapsis and crossing over between sister chromosomes, similar to known clonal lineages in fish and reptiles. Discussion: The occurrence of clonal reproduction in female hybrid catfish suggests a unique model for studying gametogenic alterations caused by hybridization and their potential for asexual reproduction. Our results further support the view that clonal reproduction in certain hybrid animals relies on intrinsic mechanisms of sexually reproducing parental species, given their multiple independent origins with the same mechanism. [ABSTRACT FROM AUTHOR]

Facultative parthenogenesis is a form of reproduction in which females can either lay unfertilised eggs that typically develop into female offspring only or mate and lay fertilised eggs that develop into male and female offspring. Intriguingly, facultative parthenogens often occur in mixed‐sex populations where reproduction is mostly sexual and all‐female populations where reproduction is asexual. How all‐female populations avoid invasion by males remains unknown. Here, we explored the use of pheromones in male–female communication in a facultatively parthenogenetic stick insect, the peppermint stick insect (Megacrania batesii), and compared chemical signals between females descended from sexually versus parthenogenetically reproducing populations. If parthenogenetic females release less attractive pheromones, this could help explain the persistence of all‐female populations. We found that M. batesii exhibits slight sexual dimorphism in antenna morphology, and behavioural assays provided little evidence that males could locate females solely by volatile pheromones. However, CHC profiles differed substantially between different types of females. Analysis of CHC components indicated a clear genetic difference between females descended from all‐female versus mixed‐sex populations, as well as a maternal effect of female parthenogenetic versus sexual development. Together, our results suggest that males might rely more on close‐range chemical cues to differentiate females, and chemical communication could play a role in the persistence of all‐female populations. [ABSTRACT FROM AUTHOR]

Animal morphology is influenced by several factors, including gonadal development and gametogenesis. Although their effects are well documented in male/female differentiation, much less is known about same-sex effects, such as those caused by their mode of reproduction. Here, using geometric morphometric analyses, we compare two groups of all-female triploid hybrid fish Chrosomus eos × eos-neogaeus, that differ only by their sexual and asexual reproductive strategies. We demonstrate that morphological differences arise from factors inherently associated with their mode of reproduction, with results replicated in two distinct lineages and in natural and common garden environments. Such differences provide additional insight about the costs and benefits of both reproductive strategies, which have mostly been of a demographic, population genetic, or genetic nature. In particular, these findings have important implications for the ecology of asexual organisms and contribute to the study of sex evolution by adding complexity to the paradox of sex theory. Morphology associated with reproductive strategy in animals can be difficult to isolate. Here, the authors use geometric morphometrics to study triploid hybrid Chrosomus fish that reproduce sexually and asexually, identifying morphological differences associated with reproductive strategy. [ABSTRACT FROM AUTHOR]

The importance of monitoring and management of yellow rust, caused by Puccinia striiformis f. sp. tritici (Pst), has markedly increased in Russia over recent years because of intensifying negative effects of this destructive disease on wheat production. The Pst virulence survey was conducted in 2019–2021 in the European (North‐West, Volga, North Caucasus) and Asian (Siberia) parts of Russia, and the same 109 isolates have been genotyped here with 20 SSR markers. Fifty‐three multilocus genotypes (MLGs) were detected, seven of which occurred in two or more regions. The most frequent MLG was found in three European Pst collections (except Dagestan) and Siberia. SSR‐based variation within the regional collections was low because many MLGs were closely related. Nevertheless, each collection contained relatively different small genotype groups. No clear geographic structure of the Russian Pst population was observed because the five studied regional collections shared groups of similar genotypes. The most singular SSR genotype was identified in the North‐West collection, but genotypes of four invasive isolates belonging to the PstS2 temperature‐adapted aggressive strain did not considerably differ from others. The observed heterozygosity at all SSR loci exceeded the expected one in all regional Pst collections, which could imply asexual reproduction of the pathogen. Both the SSR and virulence analyses demonstrated similar patterns of relationships between the regional Pst collections, although the magnitude of differences between the collections was larger for virulence pathotypes. However, no significant association was established between the virulence pathotypes and SSR genotypes because multiple pathotypes had the same genotype and vice versa. [ABSTRACT FROM AUTHOR]

The mode of reproduction most often seen in snakes is sexual, but studies have noted facultative parthenogenesis in at least six families. Here, we provide evidence for the first observed case of facultative parthenogenesis in a captive Jamaican boa (Chilabothrus subflavus). A 7‐year‐old female Jamaican boa, isolated since birth, was found to have produced a litter of 15 offspring. To provide molecular DNA evidence of parthenogenesis, 13 new microsatellite loci were isolated in the species. All offspring were found to be homozygous at each locus and only possess alleles found in the dam, implicating that they were born from asexual reproduction. Several developmental abnormalities, including stillbirths and spinal deformities, were noted in the litter which may be explained by their increased level of homozygosity. To preserve genetic diversity in the captive population, research should be conducted to understand the prevalence of this mode of reproduction and to guide future management decisions of this IUCN listed Vulnerable species. Research Highlights: An isolated female Jamaican boa was found to have given birth to 15 offspring.Each offspring was homozygous across 13 molecular markers, with only alleles present in the mother, indicating that they were produced from parthenogenesis. [ABSTRACT FROM AUTHOR]

In this study, we investigate the phenomenon of Swedish Natural Science sexuality education. These classes tend to provide factual knowledge, focus on the negative outcomes of sexuality, be heteronormative and include little time for discussion—like much school sexuality education across the world—and this study aims to contribute ideas about new becomings of Natural Science sexuality education. Baradian theorising was used to explore how materialities and space and time travels within the classroom can challenge often-dominant perspectives. Data were produced in a secondary school and consist of teacher-researcher discussions and participatory observations in class. A futuristic case introduced students to spaces, times and materialities that not only helped the group move beyond a medical focus but also made the sexuality education more student centred. The participating teachers suggested imaginary lust-oriented scenarios for the 15–16-year-old students as an entrance to more preventive messages in teaching. A taken-for-granted heterosexual premise was also challenged with gender-neutral words and pronouns, an exercise on how to use both condoms and dental dams, and a time travel into future possibilities for reproduction and parenting. The acknowledgement of spacetimematter intra-activity in teaching thereby enabled new becomings of Swedish Natural Science sexuality education. However, although this study suggests how dominant medical and heterosexual perspectives can be challenged, it also made visible the absence of cultural, religious, asexuality and disability perspectives in Swedish sexuality education. [ABSTRACT FROM AUTHOR]

Amomum villosum Lour. (A. villosum) is the original plant of the medicinal and culinary spice Amomi Fructus (Sharen) and is an important economic crop in the Lingnan region of China. During the cultivation and production of A. villosum, prolonged reliance on single asexual reproduction has exacerbated the degradation of its varieties, leading to inconsistent yields and quality. Building upon earlier cultivar selection efforts, this study provides a comprehensive evaluation of two newly bred A. villosum varieties (A11 and A12) from perspectives including plant traits, product characteristics, active ingredients, and multi-omics analysis. It was found that A12 plants display enhanced robustness, more aromatic fruits, higher yields, and elevated levels of bornyl acetate, A11 shows the advantage of a high camphor content, and the different metabolites and differentially expressed genes of the two varieties were significantly enriched in multiple metabolic pathways. Additionally, A12 contained more terpenoids and substances with aromatic odors such as sweet, fruity, floral, and green. Furthermore, a key gene (Wv_032842) regulating the acetylation of bornyl was discovered, and its significantly higher expression, in A12. In conclusion, this study has a guiding significance for the evaluation of germplasm resources and the breeding of excellent varieties of A. villosum. [ABSTRACT FROM AUTHOR]

Chestnut internal rot is the main disease of chestnut during postharvest storage, which causes rot and mildew of chestnut kernel and brings huge economic losses to production. In order to clarify the pathogenic bacteria and its biological characteristics, the strain ZHZF21 was obtained by tissue isolation method. The strain was identified by morphological characteristics and ITS, TUB2 and CAL multi-gene sequence analysis. The pathogenicity of strain ZHZF21 was determined by mycelial inoculation method, and its biological characteristics were studied. The results showed that the colony of strain ZHZF21 was dark green ring concentric circles, with sexual and asexual reproduction stages. This strain was clustered with Colletotrichum fructicola numbered NDSTY31 in GenBank based on multi-gene sequences. Combined with colony morphological characteristics and molecular tree, strain ZHZF21 was preliminarily identified as Colletotrichum fructicola. The brown lesions after inoculation of strain ZHZF21 were consistent with the natural symptoms. The strain ZHZF21 could grow at 5~35 °C, the optimum temperature was 25 °C, the lethal temperature was 45~50 °C, and the optimum pH was 6. Under the condition of full darkness, strain ZHZF21 grew fastest, the utilization rates of arabinose and yeast were the highest, the utilization rate of lactose was the lowest, and urea could hardly be used. [ABSTRACT FROM AUTHOR]

This paper explores the interplay between romantic family imaginaries and asexual identity-making through the agentic negotiation of pragmatic trade-offs. Romantic family imaginaries refer to ideational and aspirational aspects of idealized romantic relationships that mark them as chosen family and engender associated feelings of security and normalcy. I analysed idiographic case studies (chosen from a larger sample of 44 interviewees) of two interviewees with asexual tendencies, romantic family aspirations, and ambivalence towards asexual identification. Romantic family imaginaries accentuated ambiguities in how my interviewees experienced and labelled their asexual feelings. Extending ideas about pragmatism explored within family studies and queer Singapore studies, this research conceptually proposes two ways through which pragmatic negotiation may take place: the deployment of provisional and prospective identities. Provisional identities affirm ambiguity by tethering themselves to ongoing relationships that live out family imaginaries. Prospective identities affirm ambiguity by qualifying themselves in relation to future unknowns. Examining these trade-offs reveals how romantic and sexual normativity, usually thought to be allied, may sometimes be situationally opposed. [ABSTRACT FROM AUTHOR]

In order to investigate a new way to replace the exotic mangrove Laguncularia racemosa plantations gradually with native mangrove forests through thinning and pruning without clear-cutting of drastic habitat disturbance in the reserve, we took the exotic mangrove L. racemosa forests introduced in Hainan Dongzhai Harbor National Nature Reserve as the study area, and L. racemosa forests were thinning and pruning relying on the reserve. The purpose was to study the ecological effects of the thinning and pruning of L. racemosa forests on the restoration of native mangrove communities. The results were as follows: (1) Asexual reproduction of L. racemosa stump sprouting after thinning and pruning weakened the treatment effect, and there was no significant difference in the effects of L. racemosa stump sprouting between one intervention (50% intensity of thinning and pruning) and two interventions (50% intensity of thinning and pruning followed by an additional pruning). (2) Both intervention methods enriched native mangrove species and promoted their growth in the understory shrub layer, and the two interventions had a more significant promotion effect than the one intervention. However, there was no significant effect on the natural regeneration of mangrove seedlings in the herbaceous layer. (3) In the experiment of planting native mangrove seedlings in the three plots of non-thinning, thinning and pruning, and forest margin, the survival rates of Rhizophora stylosa and Kandelia obovata seedlings were promoted by the thinning and pruning. The effect of thinning and pruning on the growth of Rhizophora stylosa seedlings was close to the forest margin conditions, but the effect was limited. In conclusion, we suggest increasing the thinning intensity or pruning frequency based on 50% intensity thinning and pruning, carrying out artificial planting of native mangrove plants in the understory appropriately, and removing the sprouting branches from the stumps of Laguncularia racemosa, which is more conducive to the conversion of L. racemosa plantation to native mangrove community. [ABSTRACT FROM AUTHOR]

Citrate synthase catalyzes the first and the rate-limiting reaction of the tricarboxylic acid (TCA) cycle, producing citrate from the condensation of oxaloacetate and acetyl-coenzyme A. The parasitic protozoan Toxoplasma gondii has full TCA cycle activity, but its physiological roles remain poorly understood. In this study, we identified three proteins with predicted citrate synthase (CS) activities two of which were localized in the mitochondrion, including the 2-methylcitrate synthase (PrpC) that was thought to be involved in the 2-methylcitrate cycle, an alternative pathway for propionyl-CoA detoxification. Further analyses of the two mitochondrial enzymes showed that both had citrate synthase activity, but the catalytic efficiency of CS1 was much higher than that of PrpC. Consistently, the deletion of CS1 resulted in a significantly reduced flux of glucose-derived carbons into TCA cycle intermediates, leading to decreased parasite growth. In contrast, disruption of PrpC had little effect. On the other hand, simultaneous disruption of both CS1 and PrpC resulted in more severe metabolic changes and growth defects than a single deletion of either gene, suggesting that PrpC does contribute to citrate production under physiological conditions. Interestingly, deleting Δcs1 and Dprpc individually or in combination only mildly or negligibly affected the virulence of parasites in mice, suggesting that both enzymes are dispensable in vivo. The dispensability of CS1 and PrpC suggests that either the TCA cycle is not essential for the asexual reproduction of tachyzoites or there are other routes of citrate supply in the parasite mitochondrion. [ABSTRACT FROM AUTHOR]

Closely related sexual and parthenogenetic species often show distinct distribution patterns, known as geographical parthenogenesis. Similar patterns, characterized by the existence of separate sexual and parthenogenetic populations across their natural range, can also be found in facultative parthenogens – species in which every female is capable of both sexual and parthenogenetic reproduction. The underlying mechanisms driving this phenomenon in nature remain unclear. Features of the habitat, such as differences in host‐plant phenotypes or niche breadth, could favour sexual or asexual reproductive modes and thus help to explain geographical parthenogenesis in natural insect populations. Megacrania batesii is a facultatively parthenogenetic stick insect that displays geographical parthenogenesis in the wild. We aimed to explore whether sexual and parthenogenetic populations of M. batesii displayed niche differentiation or variations in niche breadth that could explain the separation of the two population types. To do this, we sampled host plants from across the range of M. batesii and quantified phenotypic traits that might affect palatability or accessibility for M. batesii, including leaf thickness, toughness, spike size and density, plant height, and chemical composition. We also quantified host‐plant density, which could affect M. batesii dispersal. We found little evidence of phenotypic differences between host plants supporting sexual versus asexual M. batesii populations, and no difference in host‐plant density or niche breadth between the two population types. Our results suggest that habitat parameters do not play a substantial role in shaping patterns of geographical parthenogenesis in wild populations of M. batesii. Instead, population sex ratio variation could result from interactions between the sexes or dispersal dynamics. [ABSTRACT FROM AUTHOR]

Many aphid species exhibit both cyclical parthenogenesis (CP) and the obligate parthenogenesis (OP) life history, which are genetically determined. In CP aphid lineages, the parthenogenetic individuals can switch from asexual to sexual reproduction quickly in response to environmental factors such as changes in photoperiod and temperature. However, the OP aphid lineages do not undergo sexual reproduction under any conditions. So far, mechanisms underlying the reproduction switch in CP aphids have not been fully elucidated. Rhopalosiphum padi, a serious worldwide insect pest of wheat, has both CP and OP lineages. Uridine diphosphate‐glycosyltransferases (UGTs) are enzymes that participate in the metabolic detoxification of xenobiotics. Here, we identified 43 RpUGT genes from R. padi genome and transcriptome sequences, and found that: (1) the UGT content of the CP lineage was significantly higher than that in the OP lineage at the key time points when CP lineage mainly produce virginoparae, gynoparae, and males under inducing condition, while there were no significant difference under normal conditions; (2) RpUGT344J7 gene was highly expressed during the time points when CP lineages produce gynopara and males; (3) the critical time points for CP lineages to produce virginoparaee, gynoparae, and males were affected when the CP lineages were injected with dsRpUGT344J7; (4) the knockdown of RpUGT344J7 caused a significant reduction in the total number of virginoparae, gynoparae, and males in the offspring under inducing condition. The findings contribute to our understanding of the molecular mechanisms underlying the quick shift from asexual to sexual reproduction in aphid species. [ABSTRACT FROM AUTHOR]

AbstractThe order Chaetothyriales encompasses black yeasts and related fungi known for their diverse morphologies, asexual reproduction, and habitat preferences. In this study, we isolated two fungal strains belonging to Chaetothyriales, designated KNUF-23-13A and KNUF-22-020, from a longhorn beetle (Cyrtoclytus capra) and soil sample, respectively, in Korea. Phylogenetic analyses based on the concatenated nucleotide sequences of the internal transcribed spacer regions and partial sequences of the large subunit (LSU) rRNA, β-tubulin (TUB2), and actin (ACT) genes revealed that the strains were grouped with strains of Trichomerium and Exophiala, respectively. For strain KNUF-23-13A, cultural and morphological differences were observed in the shape and size of mycelium between it and its phylogenetically closest species, Trichomerium lapideum CGMCC 3.17311T, supporting the novelty of this isolated species. In the case of strain KNUF-22-020, the cultural and morphological characteristics were similar to those previously reported for E. radicis P2854T. Based on morphological and phylogenetic analyses, we revealed KNUF-23-13A as a novel species, which we describe and name T. koreanum sp. nov., and KNUF-22-020 as Exophiala radicis, a previously unreported species in Korea. [ABSTRACT FROM AUTHOR]

Fungal genetic systems ideally combine molecular tools for genome manipulation and a sexual reproduction system to create an informative assortment of combinations of genomic modifications. When employing the sexual cycle to generate multi-mutants, the background genotype variations in the parents may result in progeny phenotypic variation obscuring the effects of combined mutations. Here, to mitigate this variation in Fusarium verticillioides, we generated a MAT1-2 strain that was near isogenic to the sequenced wild-type MAT1-1 strain, FGSC7600. This was accomplished by crossing FGSC7600 with the divergent wild-type MAT1-2 strain FGSC7603 followed by six sequential backcrosses (e.g., six generations) of MAT1-2 progeny to FGSC7600. We sequenced each generation and mapped recombination events. The parental cross involved twenty-six crossovers on nine of the eleven chromosomes. The dispensable chromosome 12, found in FGSC7603 but lacking in FGSC7600, was not present in the progeny post generation five. Inheritance of complete chromosomes without crossover was frequently observed. A deletion of approximately 140 kilobases, containing 54 predicted genes on chromosome 4, occurred in generation 4 and was retained in generation 5 indicating that these genes are dispensable for growth and both asexual and sexual reproduction. The final MAT1-2 strain TMRU10/35 is about 93% identical to FGSC7600. TMRU10/35 is available from the Fungal Genetics Stock Center as FGSC27326 and from the ARS Culture Collection as NRRL64809. [ABSTRACT FROM AUTHOR]

SUMMARY: Citrus is a model plant for studying adventitious embryos, a form of asexual reproduction controlled by a single dominant gene, RWP. This gene has been identified as the causal gene for nucellar embryogenesis, but its function has not yet been fully understood. In this study, we used the fast‐growing Fortunella hindsii as a system to explore chromatin accessibility during the nucellar embryony initiation, emphasizing elevated chromatin accessibility in polyembryonic (PO) genotypes compared to monoembryonic ones (MO). Notably, a higher level of accessible chromatin was observed in one allele of the promoter region of FhRWP, consistent with increased expression of the allele carrying the causal structural variant. By independently performing RNAi and gene editing experiments on PO genotypes, we found the downregulation of FhRWP expression could reduce the number of nucellar embryos, while its knockout resulted in abnormal axillary bud development. In overexpression experiments, FhRWP was identified as having the unique capability of inducing the embryogenic callus formation in MO stem segments, possibly through the regulation of the WUS‐CLV signaling network and the ABA and cytokinin pathway, marking the inaugural demonstration of FhRWP's potential to reignite somatic cells' embryogenic fate. This study reveals the pleiotropic function of RWP in citrus and constructs a regulatory network during adventitious embryo formation, providing a new tool for bioengineering applications in plant regeneration. Significance Statement: FhRWP plays a central role in regulating multiple developmental phenotypes, including axillary bud differentiation, nucellar embryo formation, and somatic embryogenesis in citrus. [ABSTRACT FROM AUTHOR]

Identifying characteristics of invasive species or growth forms that facilitate their range expansion is critical for management. Clematis vitalba L. (old man's beard) is an invasive temperate liana in many areas of its introduction, yet its seedlings do not thrive in circumstances where resources are limited. Although some lianas in both tropical and temperate climates have been shown to spread by clonal stems along the ground, the bulk of previous research on C. vitalba reproduction has focused largely on aspects of seed ecology. The vegetative growth of the species is poorly understood. The first objective of our study was to evaluate the use of vegetative spread by C. vitalba as a means of local dispersal and population growth. We excavated ten 1‐m2 plots in infested riparian zones and found an extensive, branching network of creeping stems, both above and below ground. Our second objective was to test the ability of C. vitalba stem fragments to act as vegetative propagules. After 4 months, ~50% of two‐node fragments had regenerated, from both creeping and climbing stems. These studies help explain how a temperate liana forms populations and dominate ecological communities. The findings provide good evidence that C. vitalba may rely quite heavily on asexual reproduction. In addition, the results document liana stem phenotypic plasticity; fragmented climbing stems are just as likely as fragmented creeping stems to reprogram shoot tissue systems, generate roots and regrow as independent plants. [ABSTRACT FROM AUTHOR]

Premise: Quaking aspen is a clonal tree species that has mixed ploidy, often with high relative abundance of both diploids and triploids but no haploids or tetraploids. Triploids typically have low fertility, leaving their occurrence apparently unlikely from an evolutionary perspective, unless they provide a "triploid bridge" to generating higher‐fitness tetraploids—which are not observed in this species. This study focused on how triploidy can be maintained in quaking aspen. Methods: A computational model was used to simulate gamete production, sexual reproduction, asexual reproduction, parent survival, and offspring survival in a population. All parameters were assumed to be cytotype‐dependent and environment‐independent. Sampling methods were used to identify parameter combinations consistent with observed cytotype frequencies. Results: Many processes and parameter values were sufficient to yield a moderate frequency of triploids, and very few were necessary. The most plausible route involved higher triploid survival at the parent or offspring stage and limited unreduced gamete production by either diploid or triploid parents. Triploid fertility was helpful but not necessary. Conclusions: The coexistence of diploids and triploids in quaking aspen is statistically likely and promoted by the existence of commonly observed, long‐lived triploid clones. However, other mechanisms not captured by the model related to environmental variation could also occur. Further empirical data or more complex but difficult‐to‐parameterize models are needed to gain further insight. [ABSTRACT FROM AUTHOR]

Abstract Background Arbuscular mycorrhizal fungi (AMF) form mutualistic partnerships with approximately 80% of plant species. AMF, and their diversity, play a fundamental role in plant growth, driving plant diversity, and global carbon cycles. Knowing whether AMF are sexual or asexual has fundamental consequences for how they can be used in agricultural applications. Evidence for and against sexuality in the model AMF, Rhizophagus irregularis, has been proposed. The discovery of a putative mating-type locus (MAT locus) in R. irregularis, and the previously suggested recombination among nuclei of a dikaryon R. irregularis isolate, potentially suggested sexuality. Unless undergoing frequent sexual reproduction, evolution of MAT-locus diversity is expected to be very low. Additionally, in sexual species, MAT-locus evolution is decoupled from the evolution of arbitrary genome-wide loci. Results We studied MAT-locus diversity of R. irregularis. This was then compared to diversification in a phosphate transporter gene (PTG), that is not involved in sex, and to genome-wide divergence, defined by 47,378 single nucleotide polymorphisms. Strikingly, we found unexpectedly high MAT-locus diversity indicating that either it is not involved in sex, or that AMF are highly active in sex. However, a strongly congruent evolutionary history of the MAT-locus, PTG and genome-wide arbitrary loci allows us to reject both the hypothesis that the MAT-locus is involved in mating and that the R. irregularis lineage is sexual. Conclusion Our finding shapes the approach to developing more effective AMF strains and is highly informative as it suggests that introduced strains applied in agriculture will not exchange DNA with native populations.

Abstract Gibel carp (Carassius gibelio) is a cyprinid fish that originated in eastern Eurasia and is considered as invasive in European freshwater ecosystems. The populations of gibel carp in Europe are mostly composed of asexually reproducing triploid females (i.e., reproducing by gynogenesis) and sexually reproducing diploid females and males. Although some cases of coexisting sexual and asexual reproductive forms are known in vertebrates, the molecular mechanisms maintaining such coexistence are still in question. Both reproduction modes are supposed to exhibit evolutionary and ecological advantages and disadvantages. To better understand the coexistence of these two reproduction strategies, we performed transcriptome profile analysis of gonad tissues (ovaries) and studied the differentially expressed reproduction-associated genes in sexual and asexual females. We used high-throughput RNA sequencing to generate transcriptomic profiles of gonadal tissues of triploid asexual females and males, diploid sexual males and females of gibel carp, as well as diploid individuals from two closely-related species, C. auratus and Cyprinus carpio. Using SNP clustering, we showed the close similarity of C. gibelio and C. auratus with a basal position of C. carpio to both Carassius species. Using transcriptome profile analyses, we showed that many genes and pathways are involved in both gynogenetic and sexual reproduction in C. gibelio; however, we also found that 1500 genes, including 100 genes involved in cell cycle control, meiosis, oogenesis, embryogenesis, fertilization, steroid hormone signaling, and biosynthesis were differently expressed in the ovaries of asexual and sexual females. We suggest that the overall downregulation of reproduction-associated pathways in asexual females, and their maintenance in sexual ones, allows the populations of C. gibelio to combine the evolutionary and ecological advantages of the two reproductive strategies. However, we showed that many sexual-reproduction-related genes are maintained and expressed in asexual females, suggesting that gynogenetic gibel carp retains the genetic toolkits for meiosis and sexual reproduction. These findings shed new light on the evolution of this asexual and sexual complex.

Abstract Background Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood. Results In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence. Conclusions These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.

Societal Impact Statement Summary The family Orchidaceae is renowned for its reliance on specialized pollinators and mycorrhizal symbioses. This study examined how the nonphotosynthetic orchid Gastrodia elata thrives on the dim forest floor, focusing on its pollination biology, particularly the chemical properties of pseudopollen and reproductive assurance mechanisms. It was found that G. elata mainly relies on Lasioglossum bees, attracted by its starch‐rich pseudopollen. Additionally, G. elata in the studied population can produce fruit through agamospermy (seeds from unfertilized ovules). Overall, the findings reveal that G. elata relies on fungi for nutrition and employs reproductive strategies such as mimicking pollen to attract bees and resorting to asexual reproduction when pollinators are scarce. Mycoheterotrophy is an adaptation that allows survival in environments with low irradiance and minimal competition from autotrophic plants. However, such environments can negatively impact bee pollination, as most bees prefer open habitats. Despite this, the mycoheterotrophic orchid Gastrodia elata is known to rely on Lasioglossum bees for pollination. We investigated the reproductive biology of G. elata to understand how it overcomes pollinator limitation. Our research focused on the chemical composition and anatomical basis of G. elata pseudopollen (a substance that mimics pollen and may facilitate pollination), based on micromorphological and nutritional analyses, as well as observations of pollinator behavior. Additionally, we explored the potential presence of autogamy or agamospermy as mechanisms for reproductive assurance. The pseudopollen in G. elata originates from the disintegration of the adaxial parenchymatous tissue of the callus and is rich in starch. This contrasts with pseudopollen in most orchids, which typically originates from lip hairs and whose potential attractant is protein. Lasioglossum bees pollinating G. elata visit multiple flowers and actively collect pseudopollen. Furthermore, agamospermy serves as a reproductive safeguard in shaded habitats where insect‐mediated pollination is infrequent, at least in the investigated population. Our findings suggest that Gastrodia elata pseudopollen plays an important role in enhancing insect‐mediated pollination, particularly in relatively open habitats, while agamospermy ensures fruit set in shaded environments of the investigated population. Both pseudopollen production and agamospermy likely help overcome the pollination constraints posed by the mycoheterotrophic lifestyle. [ABSTRACT FROM AUTHOR]

Centrioles are the core constituent of centrosomes, microtubule-organizing centers involved in directing mitotic spindle assembly and chromosome segregation in animal cells. In sexually reproducing species, centrioles degenerate during oogenesis and female meiosis is usually acentrosomal. Centrioles are retained during male meiosis and, in most species, are reintroduced with the sperm during fertilization, restoring centriole numbers in embryos. In contrast, the presence, origin, and function of centrioles in parthenogenetic species is unknown. We found that centrioles are maternally inherited in two species of asexual parthenogenetic nematodes and identified two different strategies for maternal inheritance evolved in the two species. In Rhabditophanes diutinus, centrioles organize the poles of the meiotic spindle and are inherited by both the polar body and embryo. In Disploscapter pachys, the two pairs of centrioles remain close together and are inherited by the embryo only. Our results suggest that maternally-inherited centrioles organize the embryonic spindle poles and act as a symmetry-breaking cue to induce embryo polarization. Thus, in these parthenogenetic nematodes, centrioles are maternally-inherited and functionally replace their sperm-inherited counterparts in sexually reproducing species. Centrioles are broken down during oogenesis and are provided by the sperm during sexual reproduction, though how centriole numbers are regulated during asexual reproduction is unclear. Here they study two asexually reproducing nematodes and identify distinct mechanisms for maternal centrosome inheritance. [ABSTRACT FROM AUTHOR]

Background The predominance of sex in eukaryotes, despite the high costs of meiosis and mating, remains an evolutionary enigma. Many theories have been proposed, none of them being conclusive on its own, and they are, in part, not well applicable to land plants. Sexual reproduction is obligate in embryophytes for the great majority of species. Scope This review compares the main forms of sexual and asexual reproduction in ferns and angiosperms, based on the generation cycling of sporophyte and gametophyte (leaving vegetative propagation aside). The benefits of sexual reproduction for maintenance of genomic integrity in comparison to asexuality are discussed in the light of developmental, evolutionary, genetic and phylogenetic studies. Conclusions Asexual reproduction represents modifications of the sexual pathway, with various forms of facultative sexuality. For sexual land plants, meiosis provides direct DNA repair mechanisms for oxidative damage in reproductive tissues. The ploidy alternations of meiosis–syngamy cycles and prolonged multicellular stages in the haploid phase in the gametophytes provide a high efficiency of purifying selection against recessive deleterious mutations. Asexual lineages might buffer effects of such mutations via polyploidy and can purge the mutational load via facultative sexuality. The role of organelle–nuclear genome compatibility for maintenance of genome integrity is not well understood. In plants in general, the costs of mating are low because of predominant hermaphroditism. Phylogenetic patterns in the archaeplastid clade suggest that high frequencies of sexuality in land plants are concomitant with a stepwise increase of intrinsic and extrinsic stress factors. Furthermore, expansion of genome size in land plants would increase the potential mutational load. Sexual reproduction appears to be essential for keeping long-term genomic integrity, and only rare combinations of extrinsic and intrinsic factors allow for shifts to asexuality. [ABSTRACT FROM AUTHOR]

A male Diachasma muliebre (Musebeck, 1956) (Hymenoptera: Braconidae), an historically reported monophagous, thelytokous parasitoid, was reared from Rhagoletis indifferens Curran, 1932 (Diptera: Tephritidae) puparia. The fly larvae were reared from Prunus emarginata (Douglas ex Hooker) Eaton (Rosaceae) fruit collected in Placer County, California in 2022. An examination of D. muliebre specimens in California collections found four additional males in the California State Collection of Arthropods, the Bohart Museum of Entomology, and the Essig Museum of Entomology. The males were collected over a 60-year period from 1962 to 2022 in Nevada, Placer and Siskiyou Counties some 272 air km apart in northern California. Possible mechanisms explaining the predominately asexual reproduction in D. muliebre and the periodic presence of males are proposed. [ABSTRACT FROM AUTHOR]

Most Mucoromycota fungi form zygospores as sexual reproductive structures. When two colonies of compatible strains meet, zygospores are formed in the area where the colonies meet. The structure and development of zygospores have been studied for a long time by light microscopy and electron microscopy. This study is the first time-lapse report on the dynamic movements of sexual and asexual reproductive processes by live imaging in Gilbertella persicaria (Choanephoraceae, Mucorales). Our live imaging analysis indicated the formation of zygospores begin immediately after two aerial hyphae contact whether at the tip or middle of the hyphae. The early-stage zygospores elongated from the contact site with a rate of 1.2-1.7 µm/s and reach < 200 µm in 2-3 h. Following maturation of zygospores, from progametangia to gametangia and maturation stage, took a few hours, in total 5 to 6 h after the first contact of two hyphae. When a zygospore was formed near the tip of hypha in contact with the partner hypha, the hyphal growth ceased. When zygospore was formed behind the tip of the hypha, the hyphal growth continued without slowing down. This study provides quantitative spatio-temporal information on the dynamics of zygospore formation. [ABSTRACT FROM AUTHOR]

Asexual lineages often exhibit broad distributions and can thrive in extreme habitats compared to their sexual counterparts. Several hypotheses can be proposed to explain this pattern. Asexual lineages could be versatile genotypes with wide environmental tolerance, enabling their dispersal and persistence across large geographic areas. Alternatively, asexual genotypes could be ecological specialists that thrive in specific environments and outcompete relative colonizing distantly related with similar conditions in the process. Several aphid species feature widespread obligate asexual lineages, commonly known as 'superclones'. Yet it is often unknown whether these clones are widespread ecological generalists or successful specialists. To explore these hypotheses, we examined climatic niche differentiation among six globally distributed obligate asexual lineages of the cosmopolitan aphid pest, Brachycaudus helichrysi. To ensure that we were investigating the aphid genotype niche and not a by‐product of their association with endosymbionts mediating thermal tolerance, we first verified that clones hosted similar endosymbiont communities. Subsequently, we conducted multivariate analyses on clone occurrence data on a worldwide scale. Our results revealed that, despite their global distribution, B. helichrysi superclones occupy different climatic niches. This study represents the first evidence that aphid superclone distribution can be mediated by distinctive ranges of climatic tolerance. [ABSTRACT FROM AUTHOR]

Transcriptome data are frequently used to investigate coral bleaching; however, the factors controlling gene expression in natural populations of these species are poorly understood. We studied two corals, Montipora capitata and Pocillopora acuta, that inhabit the sheltered Kāne'ohe Bay, Hawai'i. M. capitata colonies in the bay are outbreeding diploids, whereas P. acuta is a mixture of clonal diploids and triploids. Populations were sampled from six reefs and subjected to either control (no stress), thermal stress, pH stress, or combined pH and thermal stress treatments. RNA‐seq data were generated to test two competing hypotheses: (1) gene expression is largely independent of genotype, reflecting a shared treatment‐driven response (TDE) or, (2) genotype dominates gene expression, regardless of treatment (GDE). Our results strongly support the GDE model, even under severe stress. We suggest that post‐transcriptional processes (e.g., control of translation, protein turnover) modify the signal from the transcriptome, and may underlie the observed differences in coral bleaching sensitivity via the downstream proteome and metabolome. [ABSTRACT FROM AUTHOR]

All organisms require the ability to engage in either sexual or asexual reproduction in order to ensure their own survival. In aquaculture, when one sex outgrows the other faster, farmers use hormones to stimulate growth. Furthermore, the production of fish based on sexual dimorphism is predominantly executed through the utilization of estrogens and androgens. Environmentally, these compounds may pollute the ecosystem and cause endocrine system alterations that cause harmful effects; thus, they must be handled carefully to assure environmental, biological, and food safety. Phytoestrogens as natural non-steroidal phenolic plant chemicals that resemble 17-β-estradiol, could be employed as a safe alternative source of natural estrogens. The phytoestrogens have many biological effects due to their ability to compete with estrogen receptors, but they may negatively affect fish production, reproduction, and behaviors under controlled conditions. Thus, the current literature emphasizes on the beneficial effects of phytoestrogens on aquatic animal performance, behaviors, and some reproductive features. [ABSTRACT FROM AUTHOR]

Phoronids, together with brachiopods and bryozoans, form the animal clade Lophophorata. Modern lophophorates are quite diverse—some can biomineralize while others are soft‐bodied, they could be either solitary or colonial, and they develop through various eccentric larval stages that undergo different types of metamorphoses. The diversity of this clade is further enriched by numerous extinct fossil lineages with their own distinct body plans and life histories. In this review, I discuss how data on phoronid development, genetics, and morphology can inform our understanding of lophophorate evolution. The actinotrocha larvae of phoronids is a well documented example of intercalation of the new larval body plan, which can be used to study how new life stages emerge in animals with biphasic life cycle. The genomic and embryonic data from phoronids, in concert with studies of the fossil lophophorates, allow the more precise reconstruction of the evolution of lophophorate biomineralization. Finally, the regenerative and asexual abilities of phoronids can shed new light on the evolution of coloniality in lophophorates. As evident from those examples, Phoronida occupies a central role in the discussion of the evolution of lophophorate body plans and life histories. RESEARCH HIGHLIGHTS: Phoronida is a crucial clade for the understanding of lophophorate evolution. The recent findings on their development, combined with new fossils, allow a reconstruction of how larvae, armor, and asexuality evolved in Lophophorata. [ABSTRACT FROM AUTHOR]

Cell polarization is a multiphysics problem resulting from coupling protein pathways and cell morphological evolution. The most common example is asexual reproduction in budding yeast through Cdc42 and septin signals. However, how the interaction between the Cdc42-septin systems and the mechanical deformation of the cell surface is not well understood. To explore the interaction, we build a three-dimensional mechanochemical coupling framework to investigate the Cdc42-septin systems and elucidate how morphogenesis at the cell scale enhances the robustness of cell polarization in budding yeast. We utilize the viscous active shell model to describe the moving boundary of the cell surface, and the mechanochemical coupling is achieved through the introduction of cell surface mean curvature and active contraction-growth effects. With a normal effect of septin, numerical results demonstrate the budding processes with different transition shapes of budding profiles. On the other hand, the mechanochemical coupling problem with a weak effect of septin drives the emergence of wrinkles on the cell surface. We also apply linear perturbation analysis of the cell surface deformation to show how cell shape evolution is subjected to active contraction-growth effects. Our results show that a 3D coupled mechanochemical model can reproduce the budding morphology in yeast. Such a model provides a more comprehensive portrait of cell polarity and can be used to characterize both wild-type and mutant phenotypes such as septin mutants. • A mechanochemical model is developed to study the morphogenesis of budding yeast. • The coupling between Cdc42-septin system and active cell surface is involved. • The mean curvature of the cell surface is considered in the model. • Linear perturbation analysis is used to study the contraction-growth effect. • The appearance of wrinkling on cell surface is observed with a weak septin effect. [ABSTRACT FROM AUTHOR]

Asexuals present at health services with unique needs, yet providers typically lack training to care for this population. This narrative review aims to inform providers on best methods of asexual care. Search terms included "asexuality" and "health." Abstracts were screened against inclusion criteria, yielding 987 articles. After full-text screening, 44 papers were included. Pathologization, microaggressions, lack of awareness, and institutional neglect pose challenges to asexuals seeking care. Providers can improve asexual care by affirming identity, taking asexual-specific approaches, educating themselves, challenging biases, and fighting for institutional-level changes. These findings may guide practitioners in developing asexual-competent practices. [ABSTRACT FROM AUTHOR]

n the Neotropics, the focus of apomictic studies predominantly centres on trees within the Brazilian savanna, characterized, mostly as sporophytic and facultative, associated with polyploidy and polyembryony. To enhance our understanding of the mechanisms governing apomixis and sexual reproduction in tropical herbaceous plants, we clarify the relationship between apomixis, chromosome counts, and polyembryony in the epiphytic orchid Zygopetalum mackayi , which forms a polyploid complex within rocky outcrops in both the Brazilian savanna and the Atlantic forest. To define embryo origins and describe megasporogenesis and megagametogenesis, we performed manual self-pollinations in first-day flowers of cultivated plants, considering all three cytotypes (2 x , 3 x , 4 x) of this species. Flowers and fruits at different stages were collected to describe the development and morphology of ovules and seeds considering sexual and apomictic processes. As self-pollination treatments resulted in high fruit abortion in diploids, we also examined pollen tube development in aborted flowers and fruits to search for putative anomalies. Megasporogenesis and megagametogenesis occur regularly in all cytotypes. Apomixis is facultative and sporophytic, and associated with polyploid cytotypes, while diploid individuals exclusively engage in sexual reproduction. Polyembryony is caused mainly by the production of adventitious embryos from nucellar cells of triploids and tetraploids, but also by the development of multiple archesporia in all cytotypes. Like other apomictic angiosperms within the Brazilian savanna, our findings demonstrate that apomixis in Z. mackayi relies on pollinators for seed production. We also consider the ecological implications of these apomictic patterns in Z. mackayi within the context of habitat loss and its dependence on pollinators. [ABSTRACT FROM AUTHOR]

The "paradox of sex" refers to the question of why sexual reproduction is maintained in the wild, despite how costly it is compared to asexual reproduction. Because of these costs, one might expect nature to select for asexual reproduction, yet sex seems to be continually selected for. Multiple hypotheses have been proposed to explain this incongruence, including the niche differentiation hypothesis, the Red Queen hypothesis, and accumulation of harmful mutations in asexual species due to inefficient purifying selection. This study focuses on the accumulation of mutations in two terrestrial isopods, Trichoniscus pusillus, which has sexual diploid and parthenogenic triploid forms, and Hyloniscus riparius, an obligately sexual relative. We surveyed sex ratios of both species in an upstate New York population and obtained RNA-seq data from wild-caught individuals of both species to examine within- and between-species patterns of molecular evolution in protein-coding genes. The sex ratio and RNA-seq data together provide strong evidence that this T. pusillus population is entirely asexual and triploid, while the H. riparius population is sexual and diploid. Although all the wild T. pusillus individuals used for sequencing shared identical genotypes at nearly all SNPs, supporting a clonal origin, heterozygosity and SNP density were much higher in T. pusillus than in the sexually reproducing H. riparius. This observation suggests this parthenogenic lineage may have arisen via mating between two divergent diploid lineages. Between-species sequence comparisons showed no evidence of ineffective purifying selection in the asexual T. pusillus lineage, as measured by the ratio of nonsynonymous to synonymous substitutions (dN/dS ratios). Likewise, there was no difference between T. pusillus and H. riparius in the ratios of nonsynonymous to synonymous SNPs overall (pN/pS). However, pN/pS ratios in T. pusillus were significantly higher when considering only SNPs that may have arisen via recent mutation after the transition to parthenogenesis. Thus, these recent SNPs are consistent with the hypothesis that purifying selection is less effective against new mutations in asexual lineages, but only over long time scales. This system provides a useful model for future studies on the evolutionary tradeoffs between sexual and asexual reproduction in nature. [ABSTRACT FROM AUTHOR]

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Fusarium graminearum is the primary causative agent of Fusarium head blight (FHB), a devastating disease affecting cereals globally. The high-mobility group (HMG) of non-histone proteins constitutes vital architectural elements within chromatin, playing diverse roles in various biological processes in eukaryotic cells. Nonetheless, the specific functions of HMG proteins in F. graminearum have yet to be elucidated. Here, we identified 10 HMG proteins in F. graminearum and extensively characterized the biological roles of one HMGB protein, FgNhp6. We constructed the FgNhp6 deletion mutant and its complementary strains. With these strains, we confirmed the nuclear localization of FgNhp6 and discovered that the absence of FgNhp6 led to reduced radial growth accompanied by severe pigmentation defects, a significant reduction in conidial production, and a failure to produce perithecia. The ∆FgNhp6 mutant exhibited a markedly reduced pathogenicity on wheat coleoptiles and spikes, coupled with a significant increase in deoxynivalenol production. An RNA sequencing (RNA-seq) analysis indicated that FgNhp6 deletion influenced a wide array of metabolic pathways, particularly affecting several secondary metabolic pathways, such as sterol biosynthesis and aurofusarin biosynthesis. The findings of this study highlight the essential role of FgNhp6 in the regulation of the asexual and sexual reproduction, deoxynivalenol (DON) production, and pathogenicity of F. graminearum. [ABSTRACT FROM AUTHOR]

AbstractThis paper contributes towards the beginnings of asexual geographies, an area that has been largely overlooked within sexualities and queer geographies. Indeed, despite gradually increasing awareness of asexuality as a concept and identity, asexuality remains an underdeveloped area of academic research and is still widely misunderstood and invisible across society. Scholarship in the burgeoning field of asexuality studies has sought to redress this invisibility by exploring asexual people’s lives, identities, and experiences. Through these explorations, asexuality scholars have developed the concept of ‘compulsory sexuality’ to describe the ways in which social norms and practices assume that all people are sexual. However, within this growing field, the spatialities of asexuality and compulsory sexuality have yet to be fully developed. In this paper, I therefore aim to bring together work in geography and asexuality studies to introduce the concept of the allosexualisation of space. Drawing from qualitative interview data collected from seven asexual people living across Ireland, I examine the ways in which participants described feeling excluded, invisible, and/or out of place in a variety of spatial contexts – illustrating how spaces can come to reflect and co-produce the logic and assumptions of compulsory sexuality. In doing so, I argue that space matters to our understandings of asexuality and asexual people’s lived experiences, as well to the ways in which compulsory sexuality is manifest throughout our everyday lives. This paper thus contributes to beginning geographical discussions of asexualities, and extends emerging research on asexuality by introducing a geographical lens. [ABSTRACT FROM AUTHOR]

Septoria pistaciarum, a causal agent of Septoria leaf spot disease of pistachio, is a fungal pathogen that causes substantial losses in the cultivation, worldwide. This study describes the first pan-genome-based survey of this phytopathogen— comprising a total of 27 isolates, with 9 isolates each from 3 regional units of Greece (Pieria, Larissa and Fthiotida). The reference isolate (SPF8) assembled into a total of 43.1  Mb, with 38.6% contained within AT-rich regions of approximately 37.5% G:C. The genomes of the 27 isolates exhibited on average 42% gene-coding and 20% repetitive regions. The genomes of isolates from the southern Fthiotida region appeared to more diverged from each other than the other regions based on SNP-derived trees, and also contained isolates similar to both the Pieria and Larissa regions. In contrast, isolates of the Pieria and Larissa were less diverse and distinct from one another. Asexual reproduction appeared to be typical, with no MAT1-2 locus detected in any isolate. Genomebased prediction of infection mode indicated hemibiotrophic and saprotrophic adaptations, consistent with its long latent phase. Gene prediction and orthology clustering generated a pan-genome-wide gene set of 21,174 loci. A total of 59 ortholog groups were predicted to contain candidate effector proteins, with 36 (61%) of these either having homologs to known effectors from other species or could be assigned predicted functions from matches to conserved domains. Overall, effector prediction suggests that S. pistaciarum employs a combination of defensive effectors with roles in suppression of host defenses, and offensive effectors with a range of cytotoxic activities. Some effector-like ortholog groups presented as divergent versions of the same protein, suggesting region-specific adaptations may have occurred. These findings provide insights and future research directions in uncovering the pathogenesis and population dynamics of S. pistaciarum toward the efficient management of Septoria leaf spot of pistachio. [ABSTRACT FROM AUTHOR]

The discovery of animal genetic (mostly also cryptic) species has known an exponential increase since molecular techniques became available. Also in non-marine ostracods (small, bivalved crustaceans with an excellent fossil record), several morphospecies have been shown to comprise several genetic species. Here, we screen 13 populations from Central Europe and the circum-Mediterranean region of the halophilic continental ostracod species Heterocypris salina with DNA sequences from a mitochondrial (COI) and a nuclear (28S) marker. We apply four species delimitation methods to show that this nominal species consists of four genetic species in both DNA datasets, and that these two sets of genetic species show mitonuclear discordance. Most investigated specimens belonged to one of these four genetic species. There was no clear correlation between geographic and genetic distances, but we found that, apart from historical processes, environmental factors such as ecoregion, seasonality and salinity might have been important drivers shaping discrete genetic diversity. Following the palaeontological literature, the H. salina species cluster is at least 11–9 Myr old. [ABSTRACT FROM AUTHOR]