Search Results (205)

In recent years, phylogenomic approaches have significantly deepened our understanding of moss diversity. These techniques have uncovered numerous previously overlooked species and provided greater clarity in resolving complex taxonomic relationships. In this context, the genus Rehubryum is particularly outstanding, because of its close morphological similarity to both Ulota and Atlantichella. The challenges posed by its segregation are addressed in this study, which integrates morphological and molecular data to reassess the circumscription of Rehubryum and its phylogenetic placement within the subtribe Lewinskyinae. Our results support the recognition of a new species, R. kiwi, and show that its inclusion within the genus further complicates the morphological delimitation of Rehubryum from Ulota, as both genera are distinguishable by only two consistent gametophytic characteristics: a submarginal leaf band of elongated cells, and the presence of geminate denticulations in the margins of the basal half of the leaf. Moreover, R. kiwi challenges the current morphological circumscription of Rehubryum itself, as it overlaps in key characteristics with its sister genus Atlantichella, rendering their morphological separation untenable. The striking interhemispheric disjunction between Rehubryum and Atlantichella raises new questions about long-distance dispersal and historical biogeography in mosses, despite these complexities at the generic level. Nevertheless, species-level distinctions remain well defined, especially in sporophytic traits and geographic distribution. These findings highlight the pervasive cryptic diversity within Orthotrichaceae, underscoring the need for integrative taxonomic frameworks that synthesize morphology, molecular phylogenetics, and biogeography to resolve evolutionary histories. Full article

Rye regeneration in anther cultures is problematic and affected by albino plants. DNA methylation changes linked to Cu²⁺ ions in the induction medium affect reprogramming microspores from gametophytic to sporophytic path. Alternations in S-adenosyl-L-methionine (SAM), glutathione (GSH), or β-glucans and changes in DNA methylation in regenerants obtained under different in vitro culture conditions suggest a crucial role of biochemical pathways. Thus, understanding epigenetic and biochemical changes arising from the action of Cu²⁺ and Zn²⁺ that participate in enzymatic complexes may stimulate progress in rye doubled haploid plant regeneration. The Methylation-Sensitive Amplified Fragment Length Polymorphism approach was implemented to identify markers related to DNA methylation and sequence changes following the quantification of variation types, including symmetric and asymmetric sequence contexts. Reverse-Phase High-Pressure Liquid Chromatography (RP-HPLC) connected with mass spectrometry was utilized to determine SAM, GSH, and glutathione disulfide, as well as phytohormones, and RP-HPLC with a fluorescence detector to study polyamines changes originating in rye regenerants due to Cu²⁺ or Zn²⁺ presence in the induction medium. Multivariate and regression analysis revealed that regenerants derived from two lines treated with Cu²⁺ and those treated with Zn²⁺ formed distinct groups based on DNA sequence and methylation markers. Zn²⁺ treated and control samples formed separate groups. Also, Cu²⁺ discriminated between controls and treated samples, but the separation was less apparent. Principal coordinate analysis explained 85% of the total variance based on sequence variation and 69% of the variance based on DNA methylation changes. Significant differences in DNA methylation characteristics were confirmed, with demethylation in the CG context explaining up to 89% of the variance across genotypes. Biochemical profiles also demonstrated differences between controls and treated samples. The changes had different effects on green and albino plant regeneration efficiency, with cadaverine (Cad) and SAM affecting regeneration parameters the most. Analyses of the enzymes depend on the Cu²⁺ or Zn²⁺ ions and are implemented in the synthesis of Cad, or SAM, which showed that some of them could be candidates for genome editing. Alternatively, manipulating SAM, GSH, and Cad may improve green plant regeneration efficiency in rye. Full article

Abiotic stress can reprogram the gametophytic pathway; the mechanisms by which floral bud pre-treatment influences microspore embryogenesis initiation remain unclear. In this study, we use bisulfite sequencing, sRNA-seq, and RNA-seq to analyze the dynamic changes in rice microspores under different cold treatment durations. Our results showed that a 10-day cold treatment is essential for CXJ microspore embryogenesis initiation. DNA methylation levels showed a slight change at CG, CHG, and CHH sites under cold treatment. The number of both hyper- and hypomethylated DMRs increased over cold treatment, with more hypermethylated DMRs at 5 and 10 dpt. Hypermethylated DMRs were more frequently in the TSS region compared to hypomethylated DMRs. The proportion of 24 nt sRNAs increased upon cold stress, with more downregulated than upregulated sRNAs at 10 dpt. The number of DMR target DEGs increased from 5 to 10 dpt. Promoter hypomethylation at the CHH site was more frequently associated with DEGs. These outcomes suggested that the RdDM pathway participates in the initiation of rice ME. GO analysis indicated that DMR target DEGs at 10 dpt were enriched in responses to chemical stimuli, biological processes, and stress responses. An auxin-related gene, OsHOX28, was further identified. Its upregulation, potentially mediated by the RdDM pathway, may play a crucial role in the initiation of rice ME. This study provides more information on epigenetic mechanisms during rice ME. Full article

A combination of high potential productivity and ecological stability is essential for current cultivars, which is achievable by breeding. Interspecific/intergeneric hybridization remains a key approach to producing new high-yielding and resistant cultivars. Interspecific reproductive barriers (IRBs) appear in the interaction between the pollen and pistil of interspecific/intergeneric hybrids. The mechanisms underlying these hybridization barriers are to a considerable degree unknown. The pollen–pistil interaction is decisive because the pollen of distantly related plant species either is not recognized by stigma cells or is recognized as foreign, preventing pollen tube (PT) germination and/or penetration into the stigma/style/ovary. This review mainly focuses on (1) the pollen–pistil system; (2) IRB classification; (3) similarity and differences in the function of self-incompatibility (SI) barriers and IRBs; and (4) physiological and biochemical control of IRBs and their overcoming. The main goal is to illuminate the physiological, biochemical, and molecular mechanisms underlying the growth arrest of incompatible PTs and their death. In general, this review consolidates the current understanding of the interaction of the male gametophyte with the sporophyte tissues of the pistil and outlines future research directions in the area of plant reproductive biology. Full article

Over recent decades, widespread declines of kelp forests have been reported along the European coast, prompting the need for effective and scalable restoration strategies. The green gravel technique, in which kelp gametophytes are seeded onto small rocks and cultivated in the lab before being outplanted, has shown promising results. In this study, we tested the effects of four commonly available substrates—granite, limestone, quartz, and schist—on the early development of Laminaria ochroleuca recruits under optimal laboratory conditions. All substrates supported gametophyte adhesion and sporophyte development. By week 6, quartz promoted the greatest recruit length (1.25 ± 0.16 mm), with quartz and limestone (1.54 ± 0.17 and 1.58 ± 0.14 mm, respectively) showing the best overall performance by week 7. Final recruit densities were similar across substrates, indicating multiple materials can support early development. Quartz and limestone showed both biological effectiveness and practical advantages, with limestone emerging as the most cost-effective option. Substrate selection should consider not only biological performance but also economic and logistical factors. These findings contribute to refining green gravel protocols and improving the feasibility of large-scale kelp forest restoration, although field validation is necessary to assess long-term outcomes under natural conditions. Full article

Pollen, the male gametophyte of flowering plants, is collected by honeybees as a primary source of protein and converted into bee pollen through the enzymatic activity of digestive secretions. The nutrients in bee pollen are available in amounts well beyond those of proteins, comprising macronutrients such as carbohydrates, lipids and dietary fiber, as well as micronutrients such as minerals, vitamins, organic acids, and phenolic compounds. This study aimed to determine the macro and trace mineral content of bee pollen from different botanical and geographical origins, and to assess their bioaccessibility through simulated in vitro digestion, their dietary contribution, and potential health risks. Seven bee pollen samples were investigated, three with a monofloral origin of above 80%, from Nigella spp., Helianthus annuus and Castanea sativa, and four with a multifloral origin. Mineral composition revealed potassium as the most abundant element, while iron, manganese, and copper were found at trace levels. Castanea sativa pollen had the highest overall mineral content, whereas Nigella spp. showed the lowest values for calcium, magnesium, and copper. The bioaccessibility of bee pollen was highest during the gastric phase for most minerals except copper, where most of the samples peaked in the intestinal phase. Overall, mineral bioaccessibility after simulated digestion followed the order K > Mg > Cu > Ca > Mn > Fe > Zn. While for manganese, the consumption of bee pollen showed the highest contribution to recommended dietary intake (16% for women and 12% for men), calcium had the lowest, with less than 1% of the RDA at a consumption level of 40 g/day. Health risk assessment confirmed that consuming 40 g/day of bee pollen poses no risk because the target hazard quotient and hazard index are below the risk threshold of 1.0. Full article

The female gametophyte is central to the reproductive success of flowering plants, with its development being tightly controlled by an intricate network of genes and signaling pathways. A deeper understanding of these regulatory mechanisms is essential for uncovering the complexities of plant growth and development. Recent studies have shed light on various aspects of female gametophyte development, highlighting the role of specific gene and signaling networks. Among these, the ERECTA family of leucine-rich repeat receptor-like kinase (RLK) in Arabidopsis thaliana has emerged as a key player, influencing multiple biological processes, particularly those governing reproductive development of the female gametophyte. This review focuses on the significant progress made in understanding the ERECTA family’s involvement in germline cell development, emphasizing its functional roles and signaling mechanisms in female gametophyte development. Full article

Cannabis sativa L. is a dioecious species known to produce over 1600 chemical constituents, including more than 180 cannabinoids classified into 11 structural groups. These bioactive compounds are predominantly synthesised in the glandular trichomes of female inflorescences. However, sex determination in C. sativa is influenced by both genetic and environmental factors, often leading to the development of male flowers on female plants. This unintended fertilisation reduces cannabinoid yield and increases genetic heterogeneity and challenges in medical cannabis production. Haploid and doubled haploid (DH) technologies offer a promising solution by rapidly generating homozygous lines from gametophytic (e.g., unpollinated ovaries and ovules) or sporophytic tissues (e.g., anthers and microspores) via in vitro culture or chromosome reduction during hybridisation. In land plants, the life cycle alternates between a diploid sporophyte and a haploid gametophyte generation, both capable of mitotic division to form multicellular bodies. A single genome regulates this phase transition and encodes the molecular, genetic, and epigenetic mechanisms that precisely control the developmental processes unique to each generation. While the application of haploid technology in C. sativa remains limited, through recent progress in haploid induction (HI) and CRISPR-based genome editing, the direct modification of haploid gametes or embryos enables the creation of null homozygous lines following chromosome doubling, improving genetic uniformity. Understanding the molecular mechanisms of spontaneous chromosome doubling may further facilitate the development of elite cannabis genotypes. Ultimately, enhancing the efficiency of DH production and optimising genome editing approaches could significantly increase the speed of genetic improvement and cultivar development in Cannabis sativa. Full article

RNA silencing regulates diverse cellular processes in plants. Argonaute (AGO), Dicer-like (DCL), and RNA-dependent RNA polymerase (RDR) proteins are core components of RNA interference (RNAi). Despite their functional significance, the systematic identification and characterization of these families have remained largely unexplored in Siraitia grosvenorii. Using HMMER and Pfam analyses, we identified six SgAGO, four SgDCL, and six SgRDR genes. Phylogenetic analysis classified SgAGOs, SgDCLs, and SgRDRs into five, four, and four clades, respectively, all of which clustered closely with homologs from other Cucurbitaceae species, demonstrating lineage-specific evolutionary conservation. Promoter cis-element analysis revealed the significant enrichment of hormonal (methyl jasmonate, abscisic acid) and stress-responsive (light, hypoxia) elements, indicating their roles in environmental adaptation. Tissue-specific expression profiling showed that most SgAGO, SgDCL, and SgRDR genes were highly expressed in flowers and mid-stage fruits (35 days after pollination), while SgAGO10.1 exhibited stem-specific expression. By contrast, SgRDR1.2 displayed no tissue specificity. Notably, sex-biased expression patterns in dioecious flowers suggested the RNAi-mediated regulation of gametophyte development and their potential roles in reproductive and secondary metabolic processes. This study lays the foundation for further exploration of RNAi machinery’s role in coordinating mogroside biosynthesis and stress resilience in S. grosvenorii while providing potential targets for genetic improvement. Full article

Precursor messenger RNA (pre-mRNA) splicing is a critical post-transcriptional regulatory mechanism in gene expression. The precise splicing of pre-mRNAs is essential for plant development and responding to genetic and environmental signals. In plant sexual reproduction, gene expression regulation relies on the accurate processing of pre-mRNAs, which is fundamental for coordinating developmental programs. The alternation of generations in plants involves two key phases: gametophyte development, which produces gametes, and fertilization, which leads to the formation of a diploid sporophyte. Gametophyte and embryo development represent essential processes in plant sexual reproduction. This review focuses on summarizing and analyzing the current evidence regarding the role of pre-mRNA splicing in plant sexual reproduction, with an emphasis on its involvement in gametophyte formation and embryo development. Future challenges in understanding RNA splicing regulation in plant sexual reproduction are also discussed, particularly in modulating splicing factor levels and activities and identifying target mRNAs and non-coding RNAs regulated by these factors. This review provides crucial insights into the molecular mechanisms of plant reproductive development and offers a theoretical basis for improving plant fertility and adaptability via RNA splicing regulation. Full article

Female gametophyte development in flowering plants is a highly intricate process involving a series of tightly regulated biological events, including the establishment and differentiation of a macrospore mother cell (MMC), the formation of a functional macrospore (FM), and the subsequent development of the embryo sac. The seamless progression of these events is crucial for the completion of sexual reproduction and the alternation of generations in plants. Small RNAs are ubiquitously present in eukaryotic organisms. Based on their biogenesis, function, and involvement in biological pathways, plant small RNAs are primarily categorized into four classes: miRNAs (microRNAs), ta-siRNAs (trans-acting-siRNAs), hc-siRNAs (heterochromatic-siRNAs), and nat-siRNAs (natural antisense transcript-derived siRNAs). Current studies show that small RNAs play an important role in plant reproductive development, such as female gametophyte development and ovule development. In this review, we systematically elucidate the biogenesis and molecular mechanism of small RNAs and summarize the latest research advances on their roles in regulating megasporogenesis and megagametogenesis in plants. The aim of this review is to provide insights into the mechanisms underlying plant reproductive development through the lens of small RNAs, offering a theoretical foundation for improving crop quality, yield, genetic improvement, and breeding. Full article

The efficacy of sweet cherry production is highly dependent on the regularity of flowering events and genetic-determined relations between female sporophyte and male gametophyte, which became even more important with higher flowering temperatures caused by climate change. Special attention is paid to the genetic diversity that provides essential sources of potential temperature-tolerance genes. Our study aimed at the genetic and reproductive characterization of Balkan cherry cultivars of autochthonous origin (‘Canetova’, ‘G-2’, ‘Dolga Šiška’ and ‘Ohridska Crna’), and six potential pollenizers. To identify S-haplotypes, the polymerase chain reaction (PCR) method was used to detect the S-ribonuclease (S-RNase) and S-haplotype-specific F-box protein (SFB) alleles, combined with fragment analysis and S-RNase sequencing. Pollination experiments were performed at three Balkan localities over two flowering seasons, and the fluorescence microscopy method was used to assess the cultivars’ male/female reproductive behaviour. A novel S-RNase allele S₄₀ was identified in ‘Ohridska Crna’ for the first time. ‘Ohridska Crna’ also demonstrated the best adaptability to higher temperatures regarding primary ovule longevity. This feature makes it desirable from the aspect of breeding new cultivars that can withstand the impacts of climate change. The findings on male-female relations and their temperature dependence open up the possibility for yield prediction and smart horticultural decisions that can be made to guide cherry production. Full article

In this study, the morphological and anatomical characteristics of the growth of the internal ovules and the dynamic changes in the content of endogenous hormones during the development of Korean pine (Pinus koraiensis Siebold & Zucc.) cones were investigated in detail and their interrelationships determined. In addition, morphological examinations, paraffin section, analysis and enzyme immunoassays were performed to observe the growth and development as well as the fertilization stages of the ovules of P. koraiensis from July of the pollination year to June of the following year. From July of the pollination year to May of the next year, the increase in the content of indoleacetic acid (IAA) and gibberellin and a decrease in the content of abscisic acid (ABA) in the pollination year correlated with the division of the gametophyte free nuclei. It was observed that the levels of IAA, ABA, zeatin riboside (ZR) and isopentenyl adenosine (IPA) initially decreased and then increased during overwintering, which was interpreted as a symptom of adaptation of P. koraiensis ovules to low temperatures. At the end of overwintering, the increase in IPA, ZR and ABA levels was associated with the development of the female gametophyte. The week before fertilization was identified as the stage of oocyte division, in which growth-promoting hormones dominate. During the week of fertilization, the increase in the level of growth-inhibiting hormones correlated with fertilization. After fertilization, the increase in the level of growth-promoting hormones also correlated with early embryonic development. The levels of endogenous hormones were observed to change dynamically with the development of P. koraiensis oocytes, indicating their important role. The results of this study provide the morphological and anatomical basis for related studies on the development of the ovarian strobilus in gymnosperms. Full article

This study investigated key aspects of the reproductive potential of C. sativa cv. Helena. It focused on the development of male and female gametophytes, embryos, and endosperm formation. The developmental stages of pollen grains, embryo sacs, and their formation were revealed. The anther and development of the male gametophyte were as follows: tetrasporangiate anther, (whose wall is developed by the Dicotyledonous type and consists of the epidermis, fibrous endothecium, two middle layers, and glandular tapetum) and two-celled mature pollen. The ovule and development of the female gametophyte were characterized by an upper unilocular ovary containing two anatropous, crassinucellate, bitegmic ovules. The female gametophyte follows the Polygonum (monosporic) type. The development also includes nuclear endosperm formation and the presence of an embryo sac haustorium. A high pollen and seed viability was estimated. This fact, combined with the normal running of the processes of formation and development of the female gametophyte, embryo-, and endospermogenesis provide high reproductive potential for the studied cultivar of C. sativa. These findings contribute to a better understanding of C. sativa reproductive biology and provide valuable insights for breeding programs aimed at optimizing cultivar selection. Full article