Search Results (91)

The cultivated chrysanthemum is the most important ornamental species in the genus Chrysanthemum. However, because it is predominantly hexaploid and additionally exhibits self-incompatibility, it harbors numerous functionally redundant genes and displays extremely high heterozygosity. As a result, its genomic architecture is highly complex, making it challenging to interpret data obtained from omics analyses such as RNA-seq. To provide a genetically tractable model, we previously developed Gojo-0, a self-compatible, pure line of the diploid wild species C. seticuspe. In this study, we established Gojo-1, an improved self-compatible pure line derived from Gojo-0 and its sibling lines, exhibiting enhanced viability and culture performance. Leveraging these traits, we performed CRISPR–Cas9 editing of the AGAMOUS orthologs and successfully isolated mutants with altered floral organ morphology, demonstrating the line’s suitability for functional genomics. Comparative genome analysis showed that, aside from chromosome 1, the Gojo-1 genome is highly similar to that of Gojo-0, whose complete sequence has been determined. Taken together, these features indicate that Gojo-1 will serve as a valuable resource for future omics-based studies and a broad range of additional research applications. 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

Potato (Solanum tuberosum L.) is a globally important food crop, but its tetrasomic inheritance and diploid self-incompatibility have limited the discovery of potato genes and progress in breeding. Here, we developed an F₂ segregating population consisting of 174 lines by crossing a self-compatible genome-homozygous diploid line (Y8, female parent) with a heterozygous diploid line (IVP101, male parent), followed by selfing. Using whole-genome resequencing, we constructed a high-density genetic map containing 4464 recombinant bin markers with an average physical distance of 165.51 Kb. Phenotypic evaluation of 8 traits related to yield, tuber shape, and tuber eye number across three environments revealed significant parental differences and wide phenotypic variation within the F₂ population. QTL (Quantitative trait loci) mapping using this genetic map and multi-environment phenotypic data identified 89 QTLs, including 7 previously reported QTLs/genes. In addition, 10 QTLs were stably detected across multiple seasons (stable QTLs). Further genetic effect analysis showed that favorable alleles of these stable QTLs significantly enhanced phenotypic values. Notably, two pleiotropic QTLs were identified on chromosomes 5 and 12; the major-effect QTL on chromosome 12 (qTY-12-6, qTS-12-3, and qTE-12-4) exhibited high phenotypic variance explained (PVE). Its favorable allele from Y8 significantly increased mean tuber weight, tuber number per plant, and promoted rounder tuber shape while reducing eye number, simultaneously improving yield and quality. Collectively, this study provides a reference for genetic mapping using homozygous and heterozygous diploid parents, and the identified QTLs offer valuable genetic resources for potato breeding and molecular mechanism research, enhancing our understanding of the genetic regulation of yield, tuber shape, and eye number in potato. 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

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

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

A new conformally invariant gravitational generalization of the Born–Infeld (BI) model is proposed and analyzed from the point of view of symmetries. Taking a geometric identity involving the determinant functions det$f\left(B_{\mu \nu },F_{\mu \nu }\right)$ with the Bach $B_{\mu \nu }$ and the electromagnetic field $F_{\mu \nu }$ tensors (with the 4-dimensional Greek letter indexes), two characteristic geometrical Lagrangian densities (Lagrangians) are derived: the first Lagrangian being the square root of the determinant function $\sqrt{\left|det\left(B_{\mu \nu }+F_{\mu \nu }\right)\right|}$ (reminiscent of the standard BI model) and the second Lagrangian being the fourth root $\sqrt[4]{gdet\left(B_{\alpha \gamma }{B}_{\beta }^{\gamma }+F_{\alpha \gamma }{F}_{\beta }^{\gamma }\right)}$. It is shown, after explicit computation of the gravitational equations, that the square-root model is incompatible with the inclusion of the electromagnetic tensor, consequently forcing the nullity of $F_{\mu \nu }$. In sharp contrast, the traceless fourth-root model is fully compatible and a natural ansatz of the type $B_{\mu \rho }{B}_{\nu }^{\rho }\propto \mathrm{\Omega }\left(x\right)g_{\mu \nu }$ (conformal-Killing), with $\mathrm{\Omega }$ the conformal factor and x the 4-coordinate, can be considered. Among other essential properties, the geometrical conformal Lagrangian of the fourth-root type is self-similar with respect to the determinant g of the metric tensor $g_{\mu \nu }$ and can be extended to non-Abelian fields in a way similar to the model developed by the author earlier. This self-similarity is related to the conformal properties of the model, such as the Bach currents or flows presumably of a topological origin. Possible applications and comparisons with other models are briefly discussed. Full article

Studies on the gain or loss of nectar during the course of evolution in Dendrobium Sw. (Orchidaceae) are able to provide important information concerning the reproductive biology of this enormous orchid genus and highlight reproductive barriers—in particular, changes to compatibility. By employing a literature search on the compatibility system of Dendrobium, supplemented by new experimental data of 13 taxa investigated by means of microscopy, histochemistry, and phylogenetic analysis, we aimed to ascertain whether there is, in this genus, a relationship between self-compatibility (SC) and the presence of nectar. Nectariferous plant species are thought to be visited more frequently by pollinators, resulting in geitonogamy or selfing; therefore, the presence of nectar in some Dendrobium species may promote self-incompatibility (SI), whereas a lack of nectar may increase cross-pollination. Our investigations confirmed that the capacity for nectar secretion was gained and lost several times in this genus, and that similarly organized nectar spurs were present in all species investigated, regardless of their ability to produce nectar. SI, SC, and the presence or absence of nectar have all evolved independently, but, of the 42 taxa investigated whose status both relating to nectar presence and compatibility was known, nectar was more frequent in self-incompatible taxa. Full article

The incorporation of circulating fluidized bed (CFB) fly ash into self-leveling cement-based (SLC) paste production presents significant environmental advantages. However, its addition deteriorates the fresh properties of the paste, posing challenges for practical implementation. This research examined the fresh properties of SLC paste blended with CFB fly ash, emphasizing fluidity, rheological characteristics, and bleeding rate. To enhance flowability, polycarboxylate superplasticizer (PCE) was incorporated, with particular emphasis on its interaction with CFB fly ash. The findings reveal that adding CFB fly ash to cement-based paste significantly decreased fluidity while increasing yield stress and plastic viscosity. Incorporating 20 wt.% CFB fly ash reduced paste fluidity by 51.4%, while plastic viscosity and yield stress increased by factors of 2.3 and 73, respectively. While PCE enhanced the fluidity of the blended paste, its water-reducing efficiency diminished, and the bleeding rate of the paste increased with higher CFB fly ash dosage. The water-reducing capability of PCE in the CFB fly ash-blended cement paste with 20 wt.% CFB fly ash decreased by 40.0%, and the bleeding rate of the paste increased from 0.6% to 6.7%. This effect was primarily attributed to the poor compatibility between PCE and CFB fly ash. The decline in PCE efficiency with higher CFB fly ash content, along with its lower adsorption capacity on CFB fly ash compared to cement particles, further confirmed this incompatibility. Full article

Glyoxalase I (GLYI) is a key enzyme that detoxifies methylglyoxal, a toxic byproduct of glycolysis, and is essential for plant pollination. However, the genome-wide identification and functional analysis of GLYI in Brassica rapa L. (B. rapa) remain limited. This study identified 17 BrGLYI genes (BrGLYI1–BrGLYI17) from the B. rapa genome. The self-compatible line 039-1 and the self-incompatible line GAU-28-5 were used as experimental materials, and Real-Time Quantitative Reverse Transcription PCR (RT-qPCR) was performed to examine the effect of BrGLYI genes on self-compatibility in winter B. rapa. Preliminary results showed that BrGLYI13 exhibited significant tissue specificity, with higher expression in the flowers of 039-1 compared to GAU-28-5. The open reading frame of BrGLYI13 (852 bp) was cloned from both 039-1 and GAU-28-5 cDNA, with no base mutations observed between the two lines. RT-qPCR revealed higher BrGLYI13 expression in the stigma of 039-1 compared to GAU-28-5. Based on the functional conservation and sequence homology, BrGLYI13 is speculated to play a similar role to that of AtGLYI3 in methylglyoxal detoxification and stress response. Furthermore, the knockout of AtGLYI3 resulted in reduced silique lengths and seed numbers. These findings suggest that BrGLYI13 is involved in the self-compatibility response in B. rapa and promotes the silique length and seed number in the Arabidopsis mutant, providing a basis for further research on the mechanisms of self-compatibility in B. rapa. Full article

Intraspecific diversity is often introduced in orchards to promote cross-pollination, which is essential for self-incompatible crops and beneficial for many self-compatible crops. In lychee, orchards are often planted with multiple cultivars to increase the availability of male flowers, enhancing pollen transfer to female flowers. Typically, this diversity is arranged in single-cultivar blocks, requiring pollinators to transport cross-pollen across rows to reach trees in the middle of each block. We aimed to determine the levels of outcrossing at the edge and in the middle of blocks of Fay Zee Siu, Kaimana, Kwai Mai Pink, Sah Keng, Souey Tung and Wai Chee in a multi-cultivar lychee orchard. We also aimed to determine whether outcrossed fruit have different mass, skin colour and flavour attributes from selfed fruit. All cultivars produced a mixture of outcrossed and selfed fruit. Fay Zee Siu and Kaimana fruit were predominantly outcrossed, Kwai Mai Pink produced slightly more selfed than outcrossed fruit, and Souey Tung displayed high selfing. Outcrossing levels did not differ significantly between the edge and middle rows of these four cultivars. In contrast, Sah Keng and Wai Chee produced more outcrossed fruit in their edge row but more selfed fruit in their middle row. These two cultivars were at the orchard periphery, with another cultivar planted on only one side. Pollinators transported cross-pollen 56–60 m into the middle of blocks when different cultivars were planted on both sides, but this distance decreased to 42–56 m into the blocks when another cultivar was planted on only one side. Cross-pollination had few effects on fruit mass or quality, although pollination by Souey Tung sometimes increased fruit mass or Brix. These findings suggest that interplanting different cultivars of lychee can make effective use of its mixed-mating system, providing additional pollen sources in the orchard, supporting fruitlet retention, and sustaining tree productivity, without contributing greatly to quality variation in each cultivar. Full article

The potential role of reactive oxygen species (ROS) is studied in the male gametophytes of petunia (Petunia hybrida E. Vilm.) grown in vivo with a focus on its germination, growth support in the progamic stage of fertilization, and the function of the mechanism underlying S-RNase-based self-incompatibility. Exogenous treatment with H₂O₂ influences the in vivo germination and polar growth of pollen tubes (PTs), which manifests as the acceleration or inhibition of these processes depending on its concentration, time interval after pollination, and pollination variant. The H₂O₂ treatment of the stigma somewhat stimulates the PT elongation in the late stages of self-incompatible pollination (4–8 h) versus the strong PT inhibition observed during the first hour of germination. A different pattern is observable in cross-compatible pollination: the H₂O₂ treatment of pistils inhibits PT growth during the overall pollination at all tested concentrations. Treatment of pistils with the NADPH oxidase inhibitor diphenylene iodonium chloride (DPI) strongly inhibited the growth of PTs in both pollination variants. In addition, DCF-DA staining confirms that ROS are formed in pollen, PTs, stigma of nonpollinated pistil, and the pistil itself in all pollination variants. The PT growth during the function of the self-incompatibility mechanism is arrested at high ROS concentrations, which is presumably associated with the SI-induced programmed cell death. Our results demonstrate that ROS are a necessary component of pollen, PTs, exudate, and stigma cells and contribute to successful reproduction. This study provides a deeper insight into the ROS functions during the PT growth in an in vivo system. Full article

Apple (Malus domestica) is self-incompatible and typically requires cross-pollination for seed and fruit development. Parthenocarpy (fruit development without fertilization) and self-compatibility (fruit set without external pollen) are highly desirable traits in apple breeding, as they ensure consistent fruit production and quality without cross-pollination. However, apple parthenocarpic and self-compatible accessions have not been available for practical breeding. To identify these accessions, we analysed 436 accessions of Malus domestica and 84 accessions of wild Malus species by assessing fruit production. Flowers were bagged before opening to prevent cross-pollination. If fruit developed from the bagged flowers, it indicated the presence of self-compatibility or parthenocarpy, depending on whether the fruit contained seeds. We observed and scored a range of phenotypic expressions among accessions, from weak to strong in both parthenocarpy and potential self-compatibility. Strong parthenocarpy was observed in 5.95% of wild Malus species accessions and 3.44% of M. domestica accessions. Similarly, strong self-compatibility was exhibited in 5.95% of wild Malus species accessions and 2.75% of M. domestica accessions. Although bagged flowers showed lower fruit set rates than open-pollinated (OP) flowers, fruit size, weight, firmness, and soluble sugar and starch content showed no significant differences between fruits produced from bagged and OP flowers. Furthermore, a genome-wide association study (GWAS) was conducted with a high-throughput SNP array. This analysis identified several genes potentially associated with these traits. This research provides parthenocarpic and self-compatible apple accessions for breeding, which can generate novel cultivars that eliminate the need for cross-pollination or produce seedless fruit without pollination. Full article

Self-incompatibility (SI) is a complex mechanism that prevents plants from self-fertilizing to preserve and promote genetic variability. The angiosperm species have developed two different SI systems, the sporophytic (SSI) and the gametophytic (GSI) systems. SI is a significant impediment to steady fruit production in fruit tree species of the Rosaceae. In Rosaceae, GSI is genetically regulated via a single locus, named the ‘S-locus’, which includes a minimum of two polymorphic and relatively intercorrelated S genes: a pistil-expressed S-RNase gene and several pollen-expressed SFBB (S-locus F-Box Brothers) or SFB (S haplotype-specific F-box protein). This necessitates the interaction of S-RNases with the male determinants. Although genetic and molecular analyses of S genes have shown that mutations in both pistils and pollen-specific components induce self-compatibility in many species and cultivars, other genes or molecules outside the S-locus can co-participate in the male gamete rejection in GSI. However, we highlight and synthesize the most recent knowledge on different mechanisms of GSI in Rosaceae in this current review. Full article