Sexual Reproduction Research Articles

A novel sexual system in male gametophytes of Laminaria pallida (Phaeophyceae)

ABSTRACT Brown algae (Phaeophyceae) exhibit a wide diversity of sexual systems, reproductive modes and life histories. The evolution of this diversity has often involved transitions between sexual systems, which may influence genetic diversity and diversification, and phenotypic evolution. This study reports a novel sexual system in kelp. We identified male gametophyte strains of Laminaria pallida that, despite presenting morphological features typical of a male, developed both antheridia and egg-like structures, which suggest an incomplete suppression of femaleness during sexual determination of gametophytes. The sperm released by these variant male gametophytes successfully fertilize eggs produced by female gametophytes, developing into sporophytes with normal morphologies. However, morphologically abnormal sporophytic offspring were formed in isolated variant male gametophytes, indicating that the egg-like structures were not successfully self-fertilized by sperm. The causes of the unsuccessful intragametophytic selfing are unknown, but absence of pheromone production by the egg-like structures is a hypothesis suggested by available evidence. Partial co-sexuality is clearly inherited, as all male gametophyte strains descended from the same sporophyte developed egg-like structures. Further investigation into the genetics and maturation of male partheno-sporophytes will help to estimate the potential effects of this mechanism on natural populations.

From death comes life: Large vertebrate carrion enhances seedling establishment in clonal ericaceous shrubs

Abstract Carrion can have disproportionally large effects on ecological processes and community dynamics. During decomposition, the influx of growth‐limiting nutrients can create small‐scale disturbances with high soil cover known as ‘cadaver decomposition islands’ (CDIs). Such disturbances can allow for altered plant species composition, increased biomass production or provide microsites for regeneration. Carcasses also provide a resource for omnivorous scavengers, which have the potential to direct endozoochorous seed dispersal towards developing CDIs. In this study, we investigated functional links between the scavenger community, carcass‐induced disturbances in vegetation and the seedling establishment of berry‐producing ericaceous species. We experimentally placed out 30 vertebrate carcasses of various species in a boreal forest ecosystem, each paired with a control and a mechanically disturbed plot to track vertebrate animal activity (i.e. dispersal vectors), vegetation changes (i.e. recruitment windows) and seedling establishment. We hypothesized that carcass size and season of experimental deposition would affect (H1) scavenger community composition and (H2) formation of CDIs, and that (H3) seedling establishment of ericaceous species is more abundant at CDIs compared with control or disturbed plots without carcass deposition. We found that carcass presence effectively created a spatiotemporal hotspot of animal activity and that 94% of observations of vertebrates at carcasses were of species with the potential for ericaceous seed dispersal. Larger carcasses (e.g. moose, reindeer) attracted similar and abundant vertebrate communities, whereas observations at small carcasses (e.g. red fox) resembled those at control plots (H1). Only larger carcasses led to CDI formation (i.e. potential recruitment microsites), while plots with small carcasses resembled control plots (H2). Surprisingly, the season of carcass deposition did not influence vertebrate composition at carcass plots or CDI formation (H1–2). Seedlings were significantly more abundant in CDIs compared with mechanical disturbance and control plots (H3). Overall, CDIs contained about 4 and 19 times more seedlings compared with disturbed and controls, respectively. Our study demonstrates how individual carcasses in a boreal forest landscape can facilitate sexual reproduction in ericaceous keystone species. We suggest that this pathway also occurs in other ecosystems and that it may contribute to the genetic diversity of plant populations. Read the free Plain Language Summary for this article on the Journal blog.

Variants of a major DNA satellite discriminate parental subgenomes in a hybrid parthenogenetic lizard Darevskia unisexualis (Darevsky, 1966).

Hybrid parthenogenetic animals are an exceptionally interesting model for studying the mechanisms and evolution of sexual and asexual reproduction. A diploid parthenogenetic lizard Darevskia unisexualis is a result of an ancestral cross between a maternal species Darevskia raddei nairensis and a paternal species Darevskia valentini and presents a unique opportunity for a cytogenetic and computational analysis of a hybrid karyotype. Our previous results demonstrated a significant divergence between the pericentromeric DNA sequences of the parental Darevskia species; however, an in-depth comparative study of their pericentromeres is still lacking. Here, using target sequencing of microdissected pericentromeric regions, we reveal and compare the repertoires of the pericentromeric tandem repeats of the parental Darevskia lizards. We found species-specific sequences of the major pericentromeric tandem repeat CLsat, which allowed computational prediction and experimental validation of fluorescent DNA probes discriminating parental chromosomes within the hybrid karyotype of D. unisexualis. Moreover, we have implemented a generalizable computational method, based on the optimization of the Levenshtein distance between tandem repeat monomers, for finding species-specific fluorescent probes for pericentromere staining. In total, we anticipate that our comparative analysis of Darevskia pericentromeric repeats, the species-specific fluorescent probes that we found and the pipeline that we developed will form a basis for the future detailed cytogenomic studies of a wide range of natural and laboratory hybrids.

Divine vulgarism: theorising the culturally sanctioned vulgarities

ABSTRACT This paper examines vulgarity’s cultural significance among the Zeliangrong Naga of Nagaland, Assam and Manipur. It is a sociological analysis of the ritual and social statuses maintained by senexes through ritualised vulgarities. The paper contends that vulgarities are not inherently vile. Vulgarities are believed to have divine power to protect humans by repelling evil spirits and causing them to despise humans who revel in utterly filthy vulgarism. Understanding the mythology of creation by divine intervention and propagation through sexual reproduction necessitates understanding ritualistic vulgarities. Men give something bad, like vulgarity, a divine meaning by giving it a good purpose and controlling how it is used in culture to keep their highest social and ritual statuses.

Water properties and quality of the largest rice production region in Japan and their influence on the reproduction of zebrafish.

The health of freshwater aquarium fish and their breeding success depend critically on the quality of tap water. In general, tap water in Japan is potable, although the properties of tap water vary among regions in Japan. The city of Niigata is located in the largest rice production region of Japan. We have faced challenges concerning the reproduction of freshwater aquarium fish in Niigata. To determine whether water properties and quality affect the reproduction of aquarium fish in Niigata, we investigated the chemical properties of water and raised zebrafish in water from three different sources, namely tap water of Niigata in May, artificial freshwater (i.e., prepared via reverse osmosis), and natural spring water of Gosen, to document any effects on their sexual maturation and reproduction. We found that the tap water of Niigata was not stable throughout a year (median electrical conductivity = 147.1 μS/cm; SD = 25.6), with springtime lower than the first quartile. We also found that low concentrations of four pesticides in the tap water have been detected in May (max. concentration in 2020, bromobutide 2,000ng/L, butachlor 600ng/L, pyraclonil 200ng/L, ipfencarbazone 20ng/L). Moreover, rearing zebrafish in tap water negatively influenced both fish growth and reproduction: The sex ratio of adults was male biased (proportion of F0 male 70.8%); the average total length (30.5mm) and weight (182mg) of F0 males was decreased; the GSI of F0 females (9.7%) was decreased; the fecundity (the mating success 58.7%; the number of F1 eggs 63.1) of adults was reduced. Rearing in artificial freshwater could improve these outcomes (the sex ratio 55.7%; the total length of F0 males 31.8mm; the weight of F0 males 211mg; the GSI of F0 females 11.7%; the mating success 72.6%; the number of F1 eggs 99.0), whereas rearing in natural spring water from Gosen could improve the sex ratio (56.3%) and the weight of F0 males (200mg), but not the others. Therefore, artificial freshwater made via reverse osmosis should be used for breeding freshwater aquarium fish in rice production region like Niigata. Finally, our results demonstrate that the reproduction of freshwater aquarium fish can serve as a bioindicator of low levels of organic pollutants in tap water and thus provide a basis for evaluating the safety of tap water for human consumption.

Integrated metabolomics and transcriptomics analysis highlight key pathways involved in the somatic embryogenesis of Darjeeling tea.

Darjeeling tea is a globally renowned beverage, which faces numerous obstacles in sexual reproduction, such as self-incompatibility, poor seed germination, and viability, as well as issues with vegetative propagation. Somatic embryogenesis (SE) is a valuable method for rapid clonal propagation of Darjeeling tea. However, the metabolic regulatory mechanisms underlying SE in Darjeeling tea remain largely unknown. To address this, we conducted an integrated metabolomics and transcriptomics analysis of embryogenic callus (EC), globular embryo (GE), and heart-shaped embryo (HE). The integrated analyses showed that various genes and metabolites involved in the phenylpropanoid pathway, auxin biosynthesis pathway, gibberellin, brassinosteroid and amino acids biosynthesis pathways were differentially enriched in EC, GE, and HE. Our results revealed that despite highly up-regulated auxin biosynthesis genes YUC1, TAR1 and AAO1 in EC, endogenous indole-3-acetic acid (IAA) was significantly lower in EC than GE and HE. However, bioactive Gibberellin A4 displayed higher accumulation in EC. We also found higher BABY BOOM (BBM) and Leafy cotyledon1 (LEC1) gene expression in GE along with high accumulation of castasterone, a brassinosteroid. Total flavonoids and phenolics levels were elevated in GE and HE compared to EC, especially the phenolic compound chlorogenic acid was highly accumulated in GE. Integrated metabolome and transcriptome analysis revealed enriched metabolic pathways, including auxin biosynthesis and signal transduction, brassinosteroid, gibberellin, phenylpropanoid biosynthesis, amino acids metabolism, and transcription factors (TFs) during SE in Darjeeling tea. Notably, EC displayed lower endogenous IAA levels, conducive to maintaining differentiation, while higher IAA concentration in GE and HE was crucial for preserving embryo identity. Additionally, a negative correlation between bioactive gibberellin A4 (GA4) and IAA was observed, impacting callus growth in EC. The high accumulation of chlorogenic acid, a phenolic compound, might contribute to the low success rate in GE and HE formation in Darjeeling tea. TFs such as BBM1, LEC1, FUS3, LEA, WOX3, and WOX11 appeared to regulate gene expression, influencing SE in Darjeeling tea.

Genome-wide identification of histone lysine methyltransferases and their implications in the epigenetic regulation of eggshell formation-related genes in a trematode parasite Clonorchis sinensis.

Epigenetic writers including DNA and histone lysine methyltransferases (DNMT and HKMT, respectively) play an initiative role in the differentiation and development of eukaryotic organisms through the spatiotemporal regulation of functional gene expressions. However, the epigenetic mechanisms have long been suspected in helminth parasites lacking the major DNA methyltransferases DNMT1 and DNMT3a/3b. Very little information on the evolutionary status of the epigenetic tools and their role in regulating chromosomal genes is currently available in the parasitic trematodes. We previously suggested the probable role of a DNMT2-like protein (CsDNMT2) as a genuine epigenetic writer in a trematode parasite Clonorchis sinensis. Here, we analyzed the phylogeny of HKMT subfamily members in the liver fluke and other platyhelminth species. The platyhelminth genomes examined conserved genes for the most of SET domain-containing HKMT and Disruptor of Telomeric Silencing 1 subfamilies, while some genes were expanded specifically in certain platyhelminth genomes. Related to the high gene dosages for HKMT activities covering differential but somewhat overlapping substrate specificities, variously methylated histones were recognized throughout the tissues/organs of C. sinensis adults. The temporal expressions of genes involved in eggshell formation were gradually decreased to their lowest levels proportionally to aging, whereas those of some epigenetic tool genes were re-boosted in the later adult stages of the parasite. Furthermore, these expression levels were significantly affected by treatment with DNMT and HKMT inhibitors. Our data strongly suggest that methylated histones are potent epigenetic markers that modulate the spatiotemporal expressions of C. sinensis genes, especially those involved in sexual reproduction.

FvKex2 is required for development, virulence, and mycotoxin production in Fusarium verticillioides

Fusarium verticillioides is one of the most important fungal pathogens causing maize ear and stalk rots, thereby undermining global food security. Infected seeds are usually unhealthy for consumption due to contamination with fumonisin B1 (FB1) mycotoxin produced by the fungus as a virulence factor. Unveiling the molecular factors that determine fungal development and pathogenesis will help in the control and management of the diseases. Kex2 is a kexin-like Golgi-resident proprotein convertase that is involved in the activation of some important proproteins. Herein, we identified and functionally characterized FvKex2 in relation to F. verticillioides development and virulence by bioinformatics and functional genomics approaches. We found that FvKex2 is required for the fungal normal vegetative growth, because the growth of the ∆Fvkex2 mutant was significantly reduced on culture media compared to the wild-type and complemented strains. The mutant also produced very few conidia with morphologically abnormal shapes when compared with those from the wild type. However, the kexin-like protein was dispensable for the male role in sexual reproduction in F. verticillioides. In contrast, pathogenicity was nearly abolished on wounded maize stalks and sugarcane leaves in the absence of FvKEX2 gene, suggesting an essential role of Fvkex2 in the virulence of F. verticillioides. Furthermore, high-performance liquid chromatography analysis revealed that the ∆Fvkex2 mutant produced a significantly lower level of FB1 mycotoxin compared to the wild-type and complemented strains, consistent with the loss of virulence observed in the mutant. Taken together, our results indicate that FvKex2 is critical for vegetative growth, FB1 biosynthesis, and virulence, but dispensable for sexual reproduction in F. verticillioides. The study presents the kexin-like protein as a potential drug target for the management of the devastating maize ear and stalk rot diseases. Further studies should aim at uncovering the link between FvKex2 activity and FB1 biosynthesis genes.Key points•The kexin-like protein FvKex2 contributes significantly to the vegetative growth of Fusarium verticillioides.•The conserved protein is required for fungal conidiation and conidial morphology, but dispensable for sexual reproduction.•Deletion of FvKEX2 greatly attenuates the virulence and mycotoxin production potential of F. verticillioides.

Control of meiotic crossover interference by a proteolytic chaperone network.

Meiosis is a specialized eukaryotic division that produces genetically diverse gametes for sexual reproduction. During meiosis, homologous chromosomes pair and undergo reciprocal exchanges, called crossovers, which recombine genetic variation. Meiotic crossovers are stringently controlled with at least one obligate exchange forming per chromosome pair, while closely spaced crossovers are inhibited by interference. In Arabidopsis, crossover positions can be explained by a diffusion-mediated coarsening model, in which large, approximately evenly spaced foci of the pro-crossover E3 ligase HEI10 grow at the expense of smaller, closely spaced clusters. However, the mechanisms that control HEI10 dynamics during meiosis remain unclear. Here, through a forward genetic screen in Arabidopsis, we identified high crossover rate3 (hcr3), a dominant-negative mutant that reduces crossover interference and increases crossovers genome-wide. HCR3 encodes J3, a co-chaperone related to HSP40, which acts to target protein aggregates and biomolecular condensates to the disassembly chaperone HSP70, thereby promoting proteasomal degradation. Consistently, we show that a network of HCR3 and HSP70 chaperones facilitates proteolysis of HEI10, thereby regulating interference and the recombination landscape. These results reveal a new role for the HSP40/J3-HSP70 chaperones in regulating chromosome-wide dynamics of recombination via control of HEI10 proteolysis.

Expression of sex-specific molecular markers by Babesia bovis gametes

BackgroundBovine babesiosis caused by Babesia bovis is one of the most important tick-borne diseases of cattle in tropical and subtropical regions. Babesia bovis parasites have a complex lifecycle, including development within the mammalian host and tick vector. In the tick midgut, extracellular Babesia parasites transform into gametes that fuse to form zygotes. To date, little is known about genes and proteins expressed by male gametes.Methods and resultsWe developed a method to separate male gametes from in vitro induced B. bovis culture. Separation enabled the validation of sex-specific markers. Collected male gametocytes were observed by Giemsa-stained smear and live-cell fluorescence microscopy. Babesia male gametes were used to confirm sex-specific markers by quantitative real-time PCR. Some genes were found to be male gamete specific genes including pka, hap2, α-tubulin II and znfp2. However, α-tubulin I and ABC transporter, trap2-4 and ccp1-3 genes were found to be upregulated in culture depleted of male gametes (female-enriched). Live immunofluorescence analysis using polyclonal antibodies confirmed surface expression of HAP2 by male and TRAP2-4 by female gametes. These results revealed strong markers to distinguish between B. bovis male and female gametes.ConclusionsHerein, we describe the identification of sex-specific molecular markers essential for B. bovis sexual reproduction. These tools will enhance our understanding of the biology of sexual stages and, consequently, the development of additional strategies to control bovine babesiosis.Graphical

Salinity-mediated limitation of asexual reproduction in the colonial ascidian Polyandrocarpa zorritensis

Ascidians are among the most common invasive marine invertebrates worldwide. Many species of non-indigenous ascidians (NIAs) have successfully colonized the Mediterranean Sea, notably within anthropized coastal lagoons and harbors. Although invasive species are generally characterized by their broad ecological tolerance, different ascidian species exhibit varied responses to biotic and abiotic environmental stressors, including temperature and salinity. Acquiring a better understanding about of the impact of such parameters on ascidian life history is crucial for predicting the invasive potential of NIAs. In this study, we investigated the impact of various salinities on the reproduction of the colonial ascidian Polyandorcarpa zorritensis, a species indigenous to Peru and a thriving invader. P. zorritensis undergoes asexual reproduction via a peculiar form of budding named vasal budding and produces resistant spherules, which likely facilitated its dissemination over long distances. Despite its widespread distribution along the Pacific and Atlantic coasts, it is only found in a few Mediterranean coastal areas with a low salinity. We tested the impact of different salinity conditions on the sexual and asexual reproduction rates of P. zorritensis in a controlled laboratory setting. Our experiments showed that the rate of asexual reproduction in colonies bred at 29 or 36 ppt salinity levels, corresponding to the natural range inhabited by P. zorritensis, was higher than those grown in 40 ppt salinity, commonly found in Mediterranean marinas and harbors. The results suggest that, although P. zorritensis has been present in the Mediterranean for several decades, its potential for invasion could be constrained by an intolerance to high salinity.

Recognition of Invasive Characteristics of Areca triandra Roxb. ex Buch.-Ham. (Arecaceae), an Introduced Palm Species in Sri Lanka

Areca triandra Roxb. Ex Buch-Ham native to the Southeast Asian region has been introduced to many tropical areas including Sri Lanka. Although the common occurrence of A. triandra is noticeable in the southwest region of Sri Lanka, there was no prior study and literature available to investigate the aggressiveness and invasive potential of this species. Therefore, the objective of this research was to identify the level of invasiveness and risk level of A. triandra in natural areas by (a) assessing the distribution range, (b) identifying the biological strategies for rapid colonization through a population assessment and reproductive biology assessment. An extensive literature survey was conducted to determine the distribution range of A. triandra in Sri Lanka. A population assessment was conducted in Meethirigala Forest Reserve (MFR) and Yagirala Forest Reserve (YFR). Mature A. triandra percentage, crown cover percentage, and reproductive biology assessment were conducted by establishing six 20 m×20 m plots, and A. triandra seedling percentage was evaluated by using twenty-four 1 m×1 m plots by covering different topographic conditions such as mid-slope and valley. To evaluate the invasiveness and risk level, a protocol for the prioritization of invasive species in Sri Lanka developed by the United Nations Development Organization (UNDP) was used. Results show that the common occurrence of A. triandra was noticeable in the southwest region of Sri Lanka. The abundance of mature individuals of A. triandra account for 57% with an average crown cover of 46% and seedlings account for 69% of the ground layer. The species thrives in locations subjected to natural and anthropogenic disturbances and the high crown cover and dominance of seedlings negatively affect the understory by suppressing native vegetation. This palm is clump-forming with 66% of plants with multiple stems. Sexual reproduction produced a large number of fruits; 150-200 fruits per infructescence and an average of 370 fruits per clump. Direct observation showed that the bright red fleshy pericarp of the fruit attracts frugivores, such as the Asian Koel and Green Imperial Pigeon. Protocol criteria evaluation has resulted in A. triandra being under ―Alert‖ status with the risk level of ―Moderate‖ for the invasiveness under natural conditions. Invasive potential with dense populations, clustering stems, high canopy cover, high fruit production, and effective seed dispersal confirms that A. triandra is displacing and threatening the native ecosystems. Immediate actions should be taken to control A. triandra populations for preventing further spread in natural ecosystems. 
 Keywords: Areca triandra, Arecaceae family, Invasive species, Frugivores, Infructescence 

Evolution of parental care in haploid-diploid plants.

In bryophytes that alternate between haploid gametophytes and diploid sporophytes through sexual reproduction, sporophytes are often attached to and nurtured on the female gametophyte. A similar phenomenon is seen in Florideophyceae (a group of red algae). These systems in which a gametophyte (mother) invests nutrients in sporophytes (offspring) are ideal for studying the evolution of 'parental care' in non-animal organisms. Here, we propose a model of a haploid-diploid life cycle and examine the evolution of maternal investment in sporophytes focusing on two effects: the degree of paternal or maternal control of investment and the number of sporophytes. We find that when the female dominantly controls the investment, the evolutionarily stable level of investment is that which maximizes the expected reproductive success of the female gametophyte. The genomic conflict between maternal and paternal alleles complicates the evolutionary outcome; however, a greater male allelic effect and a higher number of sporophytes favour a higher energy investment, which may lead to evolutionary branching or run-away escalation of the investment level. This suggests that the selfishness of the paternal gene is the evolutionary driver of parental care and that complex structures such as fusion cells in red algae may have evolved to suppress it.

Abortion during the Covid-19 pandemic in Indonesia: nation’s responsibility in fulfilling women’s rights related to sexual health and reproduction

Abortion during the Covid-19 pandemic in Indonesia: nation’s responsibility in fulfilling women’s rights related to sexual health and reproduction

Growing or reproducing? Assessing the existence of a trade-off in the globose cactus Gymnocalycium monvillei.

Resource allocation in plants is a fundamental aspect of life history theory. In Cactaceae, the specific trade-off between sexual reproduction and vegetative growth has still not been studied. The aim of this work was to assess if there is a trade-off between growth and reproduction, and to analyse whether both growth and allocation to reproduction depend on size of the individual. In this study, we used Gymnocalycium monvillei, a globose cactus endemic to the mountains of central Argentina, as a model species. Specifically, we analysed the relationship of growth (percentage increase in diameter) and size of individuals (diameter) to seed production, seed mass, germination, and mean germination time. To relativize the effect of size on seed production, two variables were calculated: the ratio of seed production to plant size (RSPS), and the ratio of total seed mass to plant size (RSMS). We found that both seed production and total seed mass were significantly related to cactus size. However, growth was not related to seed mass or to seed production, even when they were relativized. Germination and mean germination time were not related to plant size or growth. In the studied species, a slow-growing globose cactus, we did not find a trade-off between growth and reproduction.

Population Genetics Assessment of the Model Coral Species Stylophora pistillata from Eilat, the Red Sea

The successful management of coral reefs necessitates understanding the genetic characteristics of reefs’ populations since levels of genetic diversity play a critical role in their resilience, enabling them to withstand environmental changes with greater efficacy. To assess the genetic diversity and connectivity of the widespread Indo-Pacific coral, Stylophora pistillata, eight microsatellite loci were employed on 380 tissue samples collected from eight sites along the northern Gulf of Eilat, Red Sea. We documented deviations from the Hardy–Weinberg equilibrium and observed low heterozygosity and high values of expected heterozygosity (0.59 and 0.82, respectively). The relatively high FST values and STRUCTURE analysis results showed population fragmentation along the short coastline (<12 km). These results signify isolation by distance, low gene flow between most populations, and possible non-random mating. These results are connected to this species’ sexual reproduction traits, a brooding coral species with planulae that settle shortly upon release with limited connectivity that are most probably further exacerbated by anthropogenic impacts imposed on Eilat’s reefs. This study provides insights into the connectivity and population genetics of S. pistillata residing in an urbanized northern Red Sea reef and reinforces the need for better management of the current MPA, employing future active coral reef restoration in the area.

Two Growing-Season Warming Partly Promoted Growth but Decreased Reproduction and Ornamental Value of Impatiens oxyanthera.

Climate warming profoundly affects the vegetative growth, flowering phenology and sexual reproduction of plants; therefore, it affects the ornamental value of wild flowers. Despite this, the extent and mechanism of the impact remain unclear. Here, we conducted a warming experiment for two growing seasons (increases of 1.89 °C in 2017 and 2.37 °C in 2018) with infrared heaters to examine the effects of warming on the ornamental value of the wild flower Impatiens oxyanthera, endemic to China, in Mount Emei. We evaluated the comprehensive ornamental value based on plant morphology and flowering characteristics using the analytic hierarchy process (AHP) and disentangled the impact of the two traits on ornamental value using principal component analysis (PCA) and the partial least squares structural equation model (PLS-SEM) under ambient and warming treatments. We hypothesized that warming would reduce the ornamental value of I. oxyanthera in terms of plant morphology and flowering traits. Our results showed that warming significantly decreased plant height and crown width and increased branch number and single-leaf area. Warming also decreased vexillum length, corolla tube length, nectar spur length and pedicel length. In addition, warming shortened flowering duration per plant and reduced flower number, while there was no significant effect on flower longevity and flower color at full-bloom stage between the control and warming treatment. Therefore, the comprehensive ornamental value under warming was lower than that under the control. Pedicel length, flower color, flower longevity and flowering duration per plant were the main factors affecting the comprehensive ornamental value. The PLS-SEM showed that warming had an indirect negative effect on ornamental value via direct negative effects on flowering traits. Collectively, these results indicate that, although promoting vegetative growth, short-term warming significantly decreased the ornamental value of I. oxyanthera due to warming-caused smaller flowers and shorter flowering duration.

A paternal signal induces endosperm proliferation upon fertilization in Arabidopsis.

In multicellular organisms, sexual reproduction relies on the formation of highly differentiated cells, the gametes, which await fertilization in a quiescent state. Upon fertilization, the cell cycle resumes. Successful development requires that male and female gametes are in the same phase of the cell cycle. The molecular mechanisms that reinstate cell division in a fertilization-dependent manner are poorly understood in both animals and plants. Using Arabidopsis, we show that a sperm-derived signal induces the proliferation of a female gamete, the central cell, precisely upon fertilization. The central cell is arrested in S phase by the activity of the RETINOBLASTOMA RELATED1 (RBR1) protein. Upon fertilization, delivery of the core cell cycle component CYCD7;1 causes RBR1 degradation and thus S phase progression, ensuring the formation of functional endosperm and, consequently, viable seeds.

An overview of genetic manipulation tools in the studies of ciliates, with emphasis on gene knockout, knockdown, and overexpression

Abstract Microorganisms have expanded our understanding of biodiversity and exhibit crucial research values. Ciliated protists are a highly differentiated group of eukaryotic microorganisms with exceptional features, such as numerous cilia, dimorphic nuclei, and genome-wide gene rearrangement, that have made them ideal research models for revealing many biological processes. Studies of the ciliate Tetrahymena thermophila have greatly advanced our understanding of RNA self-splicing and enzymatic activity, telomere biology, and the Nobel Prize-winning telomerase mechanisms. Genome rearrangement during the sexual reproduction (conjugation) of ciliates, involving the elimination of ~25–90% of germline DNA, provides an opportunity to study large-scale genome remodelling while also revealing a more thorough mode of transposon repression, i.e. Piwi-interacting small RNA-mediated DNA deletion in the somatic nucleus. Although much progress has been made, research has focused mainly on a few model species that are amenable to gene editing. For other species, although they are more suitable to address some scientific gaps, research cannot be carried out owing to limitations of genetic engineering. Here, we summarize the existing genetic engineering strategies for ciliates, expecting to provide inspiration for the development and optimization of genetic engineering tools for ciliates and other organisms cannot yet be edited genetically.

(264) Prioritizing Sexual and Reproductive Health Research and Care for People with Cystic Fibrosis: A 2023 Workshop Report From the Cystic Fibrosis Foundation Sexual Health, Reproduction, and Gender Research (SHARING) Working Group

Abstract Introduction With therapy advances, people with cystic fibrosis (CF) are living longer, healthier lives, and thus increasingly have general and CF-specific sexual and reproductive health (SRH) questions. The CF Foundation is supporting the Sexual Health, Reproduction, and Gender Research (SHARING) Working Group to identify knowledge gaps, research priorities, and infrastructure needed for CF SRH research. SHARING includes pulmonologists, nurses, research coordinators, registered dieticians, psychiatrists, endocrinologists, reproductive urologists, and community members with CF. Objective In Spring 2023, SHARING developed and distributed a SRH prioritization survey for the CF community. During the annual in-person workshop, the group used these results to establish research priorities and develop studies that would address identified knowledge gaps. Methods SHARING partnered with Community Voice, a virtual platform for people with CF and their caregivers to share their perspectives on ongoing and future CF SRH research, care, and programming. We provided a list of 15 SRH research topics and asked respondents to rank the top five. We analyzed survey results using descriptive statistics. We also summarized discussions and future key directions for CF SRH research. Results A total of 303 respondents (85% people with CF and 15% caregivers) completed the survey. Sixty-five percent of people with CF were women and 37% of the people with CF for whom caregivers responded were women/girls. The majority (95% of adults, 98% of people with CF for whom caregivers responded) identified as White; 5% of adults and 10% of people with CF for whom caregivers responded were Hispanic/Latino. The majority (73%) of people with CF were >30 years old and 68% of those with CF for whom caregivers responded were <18 years old. Table 1 summarizes respondent demographics. The top five SRH topics were: 1) effects of CF modulator therapy (elexacaftor/tezacaftor/ivacaftor, ETI) on sex hormones; 2) effects of sex hormones on CF; 3) fertility; 4) pregnancy; and 5) SRH/mental health (Figure 1). People with CF prioritized pregnancy, sexual functioning, parenthood, and menopause, while caregivers prioritized ETI effects on sex hormones, fertility, mental health, and assisted reproductive technology (ART). SRH priorities differed by gender identity. Men and caregivers of men/boys prioritized fertility, mental health, SRH care provision, sexual functioning, and ART, while women and caregivers of women/girls prioritized the effect of sex hormones in CF, pregnancy, menopause, and contraception. During workshop proceedings, SHARING identified the need for further research on the interplay between sex hormones, CF pathophysiology, ETI, fertility, and ART, and a focus on the impact of infertility on mental health for males with CF. Conclusions SRH is an important and emerging area of research in CF. Research priorities are not uniform among people with CF and their caregivers, particularly across genders. Thoughtful consideration of such perspectives can ensure that future CF SRH research is relevant and responsive to CF community needs. SRH providers should be aware of the concerns in this understudied population from research and patient care perspectives. Disclosure No.