Search Results (100)

Brazilian campos rupestres are a global center of plant endemism, but they are increasingly threatened by climate change and human activities. In this context, Sincoraea, an endemic genus of the Espinhaço Mountain Range, provides an important model for understanding how reproductive traits influence species persistence. This study investigated the floral biology, reproductive systems, nectar dynamics, and floral visitors’ interactions of several Sincoraea species through fieldwork conducted from 2023 to 2025. Floral biology and pollination were analyzed in four species, while pollen and stigma traits were examined in eight species using light and scanning electron microscopy. The flowers had white tubular corollas, diurnal anthesis, and high pollen viability during anthesis. Nectar production peaked in the morning. All recorded pollinators were hummingbirds and all species were self-incompatible, except S. burle-marxii, which was partially self-compatible. The reproductive effectiveness index was 1.00 for all species, suggesting that natural pollination provided effective conspecific pollen transfer without evidence of pollen limitation. These findings highlight the strong dependence of Sincoraea on floral visitors and emphasize the importance of conserving plant–floral visitor networks in campos rupestres. These interactions are essential for maintaining genetic diversity and the long-term stability of ecosystems. Full article

Distant hybridization in plants is a powerful tool for broadening genetic diversity and developing new varieties with improved traits. However, crosses between genetically distant species are accompanied by reproductive barriers that prevent successful fertilization. This work investigated pollen–pistil interactions during the progamic phase of fertilization in distant crosses involving four members of the Solanaceae family, using several cross combinations. In all cross combinations, pollen of all species germinated on the stigma, grew through the transmitting tissues of the style and ceased growth at a specific distance from the stigma surface. Our studies have revealed that the arrest of pollen tube growth during distant hybridization exhibits a striking similarity to that observed in the gametophytic S-RNase-based self-incompatibility mechanism of Solanaceae plants. Elucidating the mechanisms of pollen tube growth arrest during distant hybridization in Solanaceae will provide deeper insight into the nature of reproductive barriers and aid in the development of strategies to overcome them, thereby expanding the possibilities for successful hybridization between distant species and enabling the creation of valuable new varieties. Full article

Reproductive barriers severely limit interspecific hybridization success among Hydrangea macrophylla, H. paniculata, and H. arborescens, thereby restricting the combination of ornamental traits and cold hardiness. We evaluated cross-compatibility, pollen tube growth, and embryo development in both direct and reciprocal crosses involving H. macrophylla with H. paniculata and H. arborescens. Both species pairs exhibited pronounced unilateral incompatibilities. When H. macrophylla served as the maternal parent, the percentages of seedling emergence were higher, whereas reciprocal crosses produced >84% ovary swelling but resulted in almost no seedlings. Fluorescence microscopy revealed mild prezygotic barriers in direct crosses but strong inhibition of pollen germination and pollen tube growth in reciprocal crosses. Paraffin section observations showed that postzygotic barriers were the primary cause of hybrid failure, with endosperm-type abortion predominating in direct crosses and embryo-type or complete abortion in reciprocal crosses. Consistent with these abortion patterns, direct crosses maintained higher proportions of normal embryos, whereas reciprocal crosses dropped below 10% at the globular stage and approached 0% at later stages. These findings support the use of timely embryo rescue for direct crosses and targeted mitigation of prezygotic barriers in reciprocal crosses to improve Hydrangea interspecific hybridization efficiency. Full article

Wolbachia is an obligate endosymbiotic alphaproteobacterium that is widely distributed among insects. It also infects the European orthopteran Chorthippus parallelus parallelus (Cpp). In this subspecies, Wolbachia induces a reproductive barrier through uni- and bidirectional cytoplasmic incompatibilities. Recently, we found that it also modifies the expression of genes related to essential physiological pathways in Cpp. Here, we have analysed the influence of Wolbachia infection on the epigenetic profiles in Cpp gonads of infected and uninfected males and females, since they constitute Wolbachia’s main target. We characterised de novo nine genes related to epigenetic mechanisms and their transcriptional activity, together with global DNA methylation levels. The results indicate that Wolbachia influences the epigenetic mechanisms in Cpp mainly in females, inducing the expression of genes related to histone deacetylation and reducing the global DNA methylation percentage. This study provides the first evidence of Wolbachia’s ability to alter epigenetic processes in Cpp, increasing our understanding of this symbiotic relationship, with potential implications for the induced reproductive isolation within and between subspecies of C. parallelus. It also offers new insights into the molecular basis of host–symbiont biology in a group for which this information is rather scarce. Full article

This study examines the reproductive biology of five widely cultivated apple cultivars in Norway (‘Discovery’, ‘Rubinstep’, ‘Red Aroma’, ‘Elstar’, and ‘Asfari’), when crossed with the main pollenizers (‘Summerred’, ‘Discovery’, ‘Katja’, ‘Rubinstep’, ‘Red Aroma’, ‘Fryd’, and ‘Eden’, and two crab apples ‘Professor Sprenger’ and ‘Dolgo’), as well as under self-pollination and open pollination. The experiment was conducted over two seasons (2022–2023) in Hardanger, a region in Western Norway. Flowering time and overlap, in vitro pollen germination, pollen tube growth within the styles and ovary, embryo sac viability, fertilization success, and fruit set were analyzed as key reproductive parameters. Under broadly comparable climatic conditions across both seasons, the results showed that both mother cultivar and the pollenizer strongly influenced progamic processes and fruit set. Pollen tube growth through the pistil was generally faster and more successful in 2022 for all pollination combinations, resulting in a higher fruit set. The only exception was ‘Elstar’, which exhibited a higher fruit set in 2023. If a single optimal pollenizer were to be selected for each apple cultivar in Western Norway, it would be ‘Red Aroma’ for ‘Discovery’ and ‘Rubinstep’; ‘Rubinstep’ for ‘Red Aroma’ and ‘Elstar’; and ‘Professor Sprenger’ for ‘Asfari’. Based on pollen tube growth in vivo and the fruit set, cultivars ‘Discovery’, ‘Rubinstep’, ‘Red Aroma’, ‘Elstar’, and ‘Asfari’ showed self-incompatibility. Full article

Self-incompatibility (SI) is a key reproductive mechanism in angiosperms that prevents self-fertilization and promotes genetic diversity while limiting breeding efficiency. Akebia trifoliata is a recently domesticated economic crop native to East Asia with medicinal, edible, and oil-producing value. However, its late-acting self-incompatibility (LSI) severely limits genetic improvement and commercial development. To investigate the molecular basis of LSI, we conducted comparative transcriptomic analyses of pistils at 48, 96, 144, 192, and 240 h after self- and cross-pollination, identifying 1552, 2954, 1302, 814, and 1978 differentially expressed genes (DEGs), respectively. DEGs were consistently enriched in mitogen-activated protein kinase (MAPK) signaling, plant hormone signal transduction, and ubiquitin-mediated proteolysis pathways, with clear transcriptional differences before and after 96 h. Compared with cross-pollinated pistils, self-pollinated pistils showed restricted pollen tube spread, and genes related to pollen recognition and tube development showed differential expression at 48 and 96 h, indicating that LSI probably occurs within the pollen tube. Collectively, these results indicate that pistils of A. trifoliata exhibit distinct early responses to self- and cross-pollination, and that DEG-enriched pathways are similar to those involved in S-RNase-mediated SI. These results provide new insights into the molecular basis of LSI and suggest potential targets for overcoming the SI barrier. Full article

Wolbachia is an endosymbiotic bacterium widespread in invertebrates that causes various reproductive effects, including cytoplasmic incompatibility, feminization, male killing, and the induction of parthenogenesis (PI). PI-Wolbachia wRem converts Telenomus remus, an egg parasitoid of Spodoptera frugiperda, from arrhenotokous reproduction (male-producing) to thelytokous reproduction (female-producing). Long-term symbiosis between egg parasitoids and Wolbachia has been shown to lead to reproductive barriers and “female functional virginity,” causing progressive and potentially irreversible sex ratio imbalances. However, whether such reproductive barriers occur in T. remus remains unknown, which has important implications for biological control programs utilizing this parasitoid. To address this question, we cured wRem using tetracycline and conducted crossing experiments with naturally uninfected strains (W-). The results indicated that the cured strain (Wcure) retained normal sexual reproductive capability, with self-crossing fertilization rates comparable to those of W- strains. However, first-generation hybridization between Wcure and W- strains produced strongly male-biased offspring (male proportion: 94.3% and 85.8% for W-♂ × Wcure♀ and Wcure♂ × W-♀, respectively), indicating substantial reproductive incompatibility. Notably, an asymmetric pattern was observed between reciprocal crosses. In second-generation hybridization experiments, hybrid females (W-/Wcure) mated with W- or Wcure males showed markedly recovered sex ratios (male proportion: 14.3% and 15.6%, respectively), although total offspring numbers remained lower than in self-crossing groups. These results suggest that the reproductive incompatibility in T. remus differs from female functional virginity and is more consistent with mitonuclear incompatibility arising from population divergence. The partial recovery in second-generation hybrids indicates that surviving F1 hybrid females likely represent individuals selected for compatibility, rather than exhibiting progressive deterioration of sexual function. These findings offer insights into Wolbachia’s impact on parasitoid reproduction and highlight key considerations for biological control applications, underscoring the importance of evaluating reproductive barriers before deploying cured strains and preventing symbiont loss within populations. Full article

The introduction of Super-High-Density (SHD) olive orchards represents a crucial innovation in modern olive growing, enhancing sustainability. However, the long-term success of these planting systems depends strongly on cultivar selection, combining suitable vegetative and reproductive traits. This three-year field study investigated key floral biology parameters—flowering phenograms, gynosterility, and self-compatibility—of ten olive cultivars grown under irrigated conditions in southern Italy: ‘Arbequina’, ‘Arbosana’, ‘Cima di Bitonto’, ‘Coratina’, ‘Don Carlo’, ‘Frantoio’, ‘Favolosa’ (=‘Fs-17’), ‘I-77’, ‘Koroneiki’, and ‘Urano’ (=‘Tosca’). Flowering phenograms varied significantly across years and cultivars, showing temporal shifts related to chilling accumulation and yield of the previous year. Early blooming cultivars (‘Arbequina’, ‘Arbosana’, and ‘Coratina’) exhibited partial flowering overlap with mid-season ones, enhancing cross-pollination opportunities. Quantitative analysis of flowering overlap revealed that most cultivar combinations exceeded the 70% threshold required for effective pollination, although specific genotypes (‘Coratina’, ‘Fs-17’, and especially ‘I-77’) showed critical mismatches, while ‘Frantoio’ and ‘Arbequina’ emerged as the most reliable pollinizers. Gynosterility exhibited statistical differences among cultivars and canopy positions: ‘I-77’ showed the highest values (71.4%), while ‘Coratina’ and ‘Cima di Bitonto’ showed the lowest ones (7.3 and 8.4%, respectively). The median portions of the canopies generally displayed a greater number of sterile flowers (29.4%), reflecting the combined effect of genetic and environmental factors such as light exposure. In the inflorescence, the majority of gynosterile flowers were concentrated in the lower part, for all canopy portions (modal value). Self-compatibility tests were performed considering a fruit set of 1% as a threshold to discriminate. For open pollination, the fruit set was highly variable among cultivars, ranging from 0.5% in ‘I-77’ to 4.7% in ‘Arbosana’. Apart from ‘I77’, all varieties achieved a fruit set greater than 1%. Instead, for the self-pollination, only ‘Arbequina’, ‘Koroneiki’, ‘Frantoio’, and ‘Cima di Bitonto’ could be identified as pseudo-self-compatible, whereas ‘Coratina’, ‘Fs-17’, and the others were clearly self-incompatible and therefore unsuitable for monovarietal orchards in areas with limited availability of pollen. By integrating self-compatibility and gynosterility data, the cultivars were ranked according to reproductive aptitude, identifying ‘Cima di Bitonto’ and ‘Frantoio’ as the most fertile genotypes, whereas ‘Don Carlo’ and particularly ‘I-77’ showed severe genetic sterility constraints. The findings underline the critical role of floral biology in defining reproductive efficiency and varietal adaptability in SHD systems. This research provides valuable insights for optimizing cultivar selection, orchard design, and management practices, contributing to the development of sustainable, climate-resilient olive production models for Mediterranean environments. Full article

Objective: The aim of this study was to systematically map evidence to inform best practices for sexual and reproductive healthcare delivered via telehealth (TeleSRH) in United States-based Title X-funded clinics. Methods: We searched three databases (2017–2025) for studies evaluating effectiveness, harms, patient and provider experiences, barriers/facilitators, and engagement strategies encompassing TeleSRH for sexually transmitted infections (STIs), contraceptive care/family planning (CC/FP), and sexual wellness, in countries with a human development index of ≥0.8. Results: From 5963 references and 436 articles, we included 142 eligible publications. TeleSRH use declined since the COVID-19 pandemic’s peak but remains higher than pre-pandemic. Evidence comes mostly from poor-quality studies. TeleSRH increases access and adherence to STI prevention (e.g., pre-exposure prophylaxis for HIV). Tele-follow-up may safely facilitate HIV care continuity. For CC/FP, TeleSRH is comparable to in-person care for patient satisfaction and uptake; patients are less likely to select long-acting reversible contraception but post-initiation tele-follow-up may increase its continuation rates. Vasectomy completion rates may be similar between pre-procedural counseling via telehealth versus in-person. TeleSRH’s potential benefits might include reduced travel time, wait times, no-show rates, and clinic human resource burden (via tele-triaging) and increased preventative screening rates for STIs and non-communicable diseases, prescription refill rates, ability to receive confidential care in preferred settings, and rural/marginalized community outreach. Implementation challenges span technological and capital constraints, provider availability, staff capability building, restrictive policies, language incompatibility, and patient mistrust. Supplementing synchronous TeleSRH with asynchronous communication (e.g., mobile application) may improve continued patient engagement. Conclusions: Preventive, diagnostic, and therapeutic TeleSRH can be effective, with high patient acceptability; however, effectiveness and adoption hinge on contextual factors outlined in this review. Full article

Loeselia mexicana (Polemoniaceae) is a Mexican shrub with significant medicinal value since pre-Hispanic times. Despite its ethnobotanical importance and apparent role in supporting pollinator communities, detailed information about its reproductive biology remains limited, hindering conservation efforts for this increasingly harvested species. We investigated the reproductive ecology of L. mexicana across two flowering seasons (2023–2024 and 2024–2025) in central Mexico through an integrated approach examining flowering phenology, floral morphology, sexual maturation sequence, nectar characteristics, floral visitors, and breeding system experiments. Flowering occurs from September to March, peaking in October. Flowers exhibit protandry, with anther dehiscence on days 1–2 and stigma receptivity from day 2 onward (flower lifespan: 2.85 ± 0.11 days). Maximum nectar production (1.46 ± 0.05 µL per flower; 193.13 ± 8.8 mg/mL) coincided with peak visitor activity. Despite possessing classic ornithophilous traits, we recorded 21 floral visitor species (5 hummingbirds, 3 hymenopterans, 13 butterflies) with similar visitation patterns, challenging previous assumptions about pollination specialization. Controlled pollination experiments confirmed self-incompatibility, with cross-pollination producing significantly more seeds than autonomous selfing. Our findings reveal that L. mexicana maintains a generalized pollination system, while protandry and self-incompatibility enforce outcrossing, providing critical baseline information for conservation strategies. Full article

Reproductive barriers to gene flow play a key role in speciation. However, as it is not always feasible to study them directly, most studies rely on genetic divergence to infer species delimitation. In order to correlate genetic distances to reproductive incompatibilities, compact groups of closely related species are needed. In this work, we explored a species complex of Baikal amphipods (Crustacea: Amphipoda: Gammaroidea), Eulimnogammarus verrucosus. Three biological species (W, S, and E), geographically isolated in Baikal, had been found to have interspecific differences exceeding the patristic distance threshold of 0.16, and a postzygotic incompatibility had been confirmed for the closest pair, W and S. Here, we expanded our knowledge on geographical distribution of the species, discovering that secondary contact between the W and S species already occurs in natural conditions near the source of the Angara River. Our experiments have shown that the three species within the E. verrucosus species complex are separated by both prezygotic and postzygotic barriers. While neither of these barriers is absolute, their combination can ensure reproductive isolation upon secondary contact of the species. The experimental system we have developed in this and previous works can provide support for testing species delimitation hypotheses based on sequencing data and further extend these results to related species for which such experiments are unfeasible. Full article

This review examines the reproductive biology of Limonium, mainly L. sinuatum and L. perezii, and explores the breeding strategies employed for these species. Limonium is one of the 20 most cultivated genera in the ornamental plant industry worldwide, with novelty sought in traits such as flower color, stem quality and disease resistance. Approximately 85% of the species in this genus present pollen/stigma dimorphism and self-incompatibility, presenting both challenges and opportunities for breeding. Breeding strategies such as interspecific hybridization, ploidy manipulation and chromosomal mutation have been used to increase the diversity of material available to breeders. In this review, we highlight how insights into reproductive biology, combined with advanced breeding techniques, can accelerate the development of fertile interspecific hybrids and broaden the genetic base for future Limonium breeding programs. Full article

Allorecognition, or distinguishing between the self and nonself within the same species, is observed in both animals and plants, particularly in the context of immune reactions and self-incompatibility in sexual reproduction. Polymorphic recognition molecules are known to be responsible for such allorecognition during fertilization. Previous studies have reported that in ascidians and flowering plants, inbreeding avoidance relies on a pair of polymorphic recognition molecules with a receptor-ligand relationship that are encoded at a single locus, the S locus (Self-incompatibility locus), but the process by which such pairs of recognition molecules emerge and evolve to become polymorphic is not known. Here, a population genetics study was carried out as a novel approach for investigating allorecognition. To study the process by which self-recognition emerges, we simulated a situation in which an allorecognizing genotype is generated from a nonallorecognizing genotype through mutation and then analyzed whether the two genotypes could coexist. The conditions under which the numbers of allorecognition alleles could increase over evolutionary time were investigated, and the generational dynamics of nonallorecognizing genotypes were analyzed. Subsequent modeling was carried out to reproduce the allorecognition mechanism in Ciona, and consistency between the simulation results and experimental data was observed. Our approach provides new insight into the evolutionary process of allorecognition. Full article

The peach landrace ‘Liuyefeitao’ exhibits the unique reproductive trait of self-compatibility combined with cross-incompatibility, contrasting with typical Prunus species in this way. In preliminary studies involving controlled pollination assays, we showed complete pollen tube arrest in cross-pollinated styles, whereas self-pollination enabled full tube elongation. S-genotyping identified a homozygous S₂S₂ genotype with intact S₂-RNase but a truncated PpSFB2 due to a frameshift mutation. Transcriptome profiling of the styles revealed 7937 differentially expressed genes (DEGs) between self- and cross-pollination treatments, with significant enrichment in plant MAPK signaling, plant–pathogen interactions, and plant hormone signaling transduction pathways (|Fold Change| ≥ 2, FDR < 0.01). Notably, PpSLFL3 (a pollen F-box gene) showed down-regulation in cross-pollinated styles, as validated by means of qRT-PCR. Protein interaction assays revealed direct binding between PpSLFL3 and S₂-RNase via Y2H and BiFC analysis, suggesting its role in mediating SCF complex-dependent degradation. We propose that insufficient PpSLFL3 expression during cross-pollination disrupts SCF ubiquitin ligase complex-mediated degradation of non-self S₂-RNase, leading to the toxic degradation of RNA in pollen tubes by S₂-RNase. This mechanism is mechanistically similar to unilateral reproductive barriers in Solanaceae but represents a novel regulatory module in Rosaceae. Our findings provide critical insights into the evolution of cross-incompatibility systems and molecular breeding strategies for Prunus species. Full article

Plant density influences interspecific interactions such as pollination and herbivory. In denser populations, pollinators find flowers more easily, increasing reproductive success and population growth. However, the same floral attractiveness also favors floral herbivory, a relationship described by Janzen and Connell as negative density dependence, considered an important mechanism for maintaining tropical diversity. This study analyzed the reproduction of Peixotoa tomentosa A. Juss. (Malpighiaceae) and Byrsonima intermedia A. Juss. (Malpighiaceae), considering population density and its influence on pollinator and herbivore attraction. The central hypothesis was that density affects fruit production. We conducted two treatments with both species: high density and low density in a preserved Brazilian savanna. We investigated fruit production, reproductive system, floral visitation rates, and the florivory rates of each species on each treatment. Our results showed that fruiting increased with density in both species. Peixotoa tomentosa is an agamospermous species, while B. intermedia is self-incompatible and relies exclusively on pollinators. Bees visited only B. intermedia, and the high-density treatment received more visits. Herbivores attacked more isolated P. tomentosa flowers. We concluded that density influences both pollination and herbivory, affecting plant reproduction, with effects mediated by the plant’s attractiveness in denser populations and by the size and quantity of flowers in single individuals. Full article