Search Results (213)

In modern agriculture, heterotic hybrids produced from hybridization of inbred lines, have shown superiority over open-pollinated and pure line varieties due to their morphological homogeneity, synchronized maturity, and yield performance. The worldwide use of heterosis in plant breeding programs has become possible due to the discovery of cytoplasmic male sterility (CMS), a phenomenon that prevents a plant from producing viable pollen. The CMS-Rf genetic systems are commonly used to produce hybrid seeds. Species from primary, secondary, and tertiary gene pools serve as sources of sterility-inducing cytoplasm in different crop plants. In this review, information on the main genetic factors that induce sterility and restore pollen fertility in F₁ hybrids of economically important cereal (rice, sorghum, maize, rye, wheat, pearl millet) and oilseed (sunflower, rapeseeds, mustard) crops are discussed. The genetic data indicate the location of putatively orthologous candidate Rf genes on syntenic chromosomes in evolutionarily related species. The cytological features of male gametophyte development associated with pollen abortion in lines with CMS are highlighted. The problem of heterotic grouping and selecting parental forms based on genetic distance is discussed. The present knowledge on the genetic resources of different cereal and oilseed crops is highly related to the availability of genomic data. Broadening the CMS source pool and the search for new pollen fertility restoration genes are relevant to avoid cytoplasm unification. Knowledge of the cytoembryological features of CMS manifestation in cereals and oilseed crops is of great importance for understanding the genetic control and practical use of this phenomenon. Utilization of wild species’ genetic resources for these purposes and applying modern techniques of the targeted genome and gene changes at the molecular, genomic, cytological and organismal levels are promising. Full article

Southern highbush blueberry (SHB, Vaccinium corymbosum, Ericaceae) enables production in warm, low-chill regions, where breeding success depends on precisely timed pollinations. To support breeding in non-traditional environments, we characterized floral staging, anther wall ontogeny, tubule formation, and pollen development in two SHB cultivars (‘Emerald’, ‘Snowchaser’) grown in commercial orchards. Floral development was divided into seven stages: dormant buds (db), five successive floral-bud stages (botA–botE), and anthesis, based on bud size, corolla exposure and pigmentation, and anther/tubule coloration. Internal events were documented by light, confocal, and scanning electron microscopy. External cues reliably separated stages and tracked male-gametophyte phases: meiosis at botB; callose-encased tetrads at botC; permanent tetrahedral tetrads after callose dissolution at botD; bicellular tetrads from botE to anthesis, released intact via poricidal dehiscence. Anther-wall differentiation followed a consistent sequence and lacked a fibrous, lignified endothecium. We therefore propose a new Ericaceous pattern for blueberry anthers, defined by a transient non-lignified subepidermal stratum. Tubules originated apically as solid outgrowths, hollowed centrifugally to a beveled pore, developed a dorsal supportive zone, and mediated poricidal release of permanent tetrads. No qualitative cultivar differences were detected. The staging framework defines operational windows for pollination, emasculation, and pollen handling in low-chill systems. Full article

Arabinogalactan proteins (AGPs: hydroxyproline-rich glycoproteins) are ubiquitous in plants and play various functions in cases of development and reproduction. In Arabidopsis thaliana some AGPs can work as markers for gametophytic cell differentiation (among others embryological structures they mark generative cell wall and/or plasma membrane, and also sperm cells). However, apart from Arabidopsis, this labeling of generative cell and sperm cells in pollen grains has only been observed in a few flowering plant species belonging to dicotyledons. No such studies are available in monocotyledons. The main aim of our study was to see whether AGPs would be present at the generative cell–vegetative cell interface in different monocotyledons (representatives of Asparagaceae, Amarylidaceae and Liliaceae), and we also wanted to test whether they would be the same AGPs as in dicotyledons. For the study, we selected Gagea lutea (L.) Ker Gawl., Ornithogalum nutans L. and Galanthus nivalis L. species that differ in shape and size of generative cells. Antibodies against arabinogalactan proteins AGPs were used, including JIM8, JIM13, JIM14, MAC207, LM2, LM14, JIM15 and JIM4. The localization of the examined compounds was determined using immunohistochemistry techniques. The key finding was that AGPs (detected with JIM8 and JIM13 antibodies) consistently mark the boundary between the generative cell and the surrounding vegetative cytoplasm, suggesting their association with the generative cell–vegetative cell interface in all species studied. Identifying such molecular markers in male gametophyte may enhance the understanding of gametophytic cell fate, sperm cell identity and the molecular mechanisms underlying fertilization. Such labeling may also be useful in studies on pollen development, species comparisons, or responses to environmental stresses. Full article

Colaconema daviesii has been described as an epi-endophyte of red algae. However, it has also been observed in vitro to colonize thalli of Macrocystis pyrifera, a giant kelp classified as a foundational organism of coastal marine ecosystems. This study aimed to determine, through co-cultivations, how C. daviesii affects the early stages of M. pyrifera, specifically gametophyte and sporophyte development. Determined were growth, oogonia formation, and gametophyte fertility, as well as sporophyte growth rate and survival. The results showed that the presence of C. daviesii negatively altered oogonia production and gametophyte fertility. Moreover, the survival of young sporophytes in co-cultures decreased. These findings demonstrate that the early developmental stages of M. pyrifera could be susceptible to infestation by a filamentous red alga, with negative consequences on fitness. Full article

Rhodomelaceae is the largest red algae family, with 158 genera and more than 1000 described nominal species. In particular, Acanthophora (Rhodomelaceae) is a red alga with erect thalli that arises from stoloniferous branches or holdfast discs, with cylindrical main axes and spine-like branchlets. The life cycle of members of this genus has been partially described; however, the female gamete (carpogonium) has not been described. Here, we present a complete description of each stage in the life cycle of Acanthophora. Thalli of this species were collected from 27 localities in the Gulf of Mexico between 2021 and 2024 and placed in a 5% formaldehyde solution in seawater. Reproductive structures were measured and characterized under stereo and optical microscopes. A total of 62 thalli were collected, of which 10 were carposporophytes, 12 male gametophytes, 1 female gametophyte, 16 vegetative thalli, and 23 tetrasporophytic thalli. A detailed description of the shape and size of the reproductive structures is presented. We documented carpogonium for the first time. The evidence here presented contributes to the description of the life cycle of the genus Acanthophora, in which structures forgotten in current works are recovered, which is of great help in the comparative phycology of the Rhodomelaceae family and Ceramiales order. Full article

Apricot (Prunus armeniaca L.) exhibits a gametophytic self-incompatibility (GSI) system. To identify the S-genotypes of the main apricot cultivars, including 133 native Chinese cultivars and 35 foreign accessions, PCR was performed using a combination of five primers based on the conserved regions of Prunus S-RNase genes. After cloning and sequencing the PCR products, the S-genotypes of all 168 apricot cultivars were determined. A total of 46 different S-RNase alleles, with 15 new alleles, were identified. For all 168 accessions, the top five most frequent S-alleles were S₈, S₁₁, S₉, S₁₆, and S₅₃. S₁₁, S₈, and S₁₆ were the most frequent in Chinese cultivars, and S₉, S₈, and S₂ were mostly found in European accessions. For Chinese apricot cultivars, the distribution of S-alleles among five geographic regions was also investigated. In Northwest China, S₁₆ was the most frequent S-allele. In the Xinjiang region, S₆₆, S₄₉, and S₁₄ were the top three most frequent S-alleles. In North China, S₈, S₁₁, and S₅₃ were the top three most frequent S-alleles. In addition, the self-compatible type, S_C, was not detected in these 133 Chinese accessions. Finally, the phylogenetic tree of apricot S-alleles indicated that there are four groups of S-RNase genes (S₉₇/S₁₀₆, S₁₄/S_14a/S₆₆, S₉/S₁₇/S₄₄, and S₂₃/S₅₃) presenting a very close relation. These results provide more data on the S-genotypes of apricot accessions, which can support future breeding programs by aiding in the selection of the appropriate parents and contributing to efficient orchard design by combining cultivars with suitable pollinizers. Full article

Seed size is a key trait affecting evolution and agronomic performance by influencing seedling establishment in natural populations and crop yields. The Arabidopsis thaliana Seed Size QTL1 (SSQ1) locus explains 10–15% of the variation in seed size. We report here that the causal gene for this locus is Tetratricopeptide Repeat Protein 2 (TPR2), which encodes a co-chaperone. Expressing TPR2 across ecotypes and genotypes showed consistent dosage effects. Each additional TPR2^Col-0 allele increased seed mass and volume by 10–14% with high reliability in Col-0, Sha, Tsu-1, and tsu2 genetic backgrounds. Reciprocal genetic crosses indicated that this locus acts maternally, consistent with female sporophytic or female gametophytic mutations. To elucidate how TPR2 regulates seed size, the biomass composition of seeds was measured. While oil content remained unchanged, sucrose levels were markedly elevated in TPR2^Col-0 transformant lines and reduced in tpr2 mutants. Interestingly, heterologous expression of TPR2^Col-0 across genetic backgrounds increased seed protein accumulation by 18% on average. Based on these changes in sucrose and protein levels, potential modes of action for TPR2 are discussed. Full article

Most sweet cherry varieties exhibit typical gametophytic self-incompatibility (GSI) characteristics, necessitating careful configuration of pollination trees to ensure adequate yields. This requirement increases the costs associated with orchard labor, management, and other related expenses. Consequently, cultivating and developing sweet cherry cultivars with self-compatibility can effectively address these challenges. Research into the molecular mechanisms underlying GSI formation can provide vital theoretical support and genetic resources for breeding self-compatible sweet cherries. In this study, we assessed the fruit set rates of ‘Tieton’ following both self- and cross-pollination. Additionally, we conducted a transcriptome analysis of the ‘Tieton’ style (which includes the stigma) at 0, 12, 24, and 48 h post-pollination to identify key genes involved in the self-incompatibility process of sweet cherries. The results indicated that the self-fruiting rate of ‘Tieton’ was significantly lower than that of cross-pollination. We identified a total of 8148 differentially expressed genes (DEGs) through transcriptome analysis, with KEGG pathway analysis revealing that the plant-pathogen interaction, plant hormone signal transduction, and plant MAPK signaling pathways were primarily involved in sweet cherry GSI. Furthermore, we identified 13 core transcription factors (TFs) based on their differential expression patterns, including three ERFs, three NACs, three WRKYs, two HD-ZIPs, one RAV, and one MYB. Co-expression analysis identified 132 core DEGs significantly associated with these TFs. Ultimately, this study provides initial insights into the key genes within the sweet cherry GSI network, laying a theoretical foundation and offering genetic resources for the future molecular design breeding of new self-compatible varieties. Full article

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