Search Results (67)

Camellia oleifera Abel. is a typical self-incompatible plant, yet its molecular mechanisms have not been comprehensively elucidated, which constitutes the principal cause underlying the relatively low natural fruit set rate in C. oleifera. S-RNase belongs to the RNase T2 gene family and represents a class of glycoproteins specifically expressed in the style with certain “cytotoxicities” capable of degrading ribonucleic acid (RNA) in their own pollen tube cells, thereby inducing programmed cell death in pollen tube cells. To identify pistil S genes participating in the self-incompatibility response of C. oleifera, nine RNase T2 family genes were identified based on transcriptomic and whole-genome sequencing data of the camellia oil tree and designated CoRNS1–CoRNS9. Systematic evolutionary analysis revealed that CoRNS5, CoRNS7, and CoRNS8 exhibit close phylogenetic relationships with S-RNases of the Camelliaceae family, whereas CoRNS6 shows closer affinity with S-RNases of the Solanaceae family. Analysis of promoter cis-acting elements revealed that RNase T2 family genes are regulated by multiple hormones, including abscisic acid, methyl jasmonate, cytokinin, auxin, salicylic acid, and gibberellin, and possess MYB transcription factor-binding sites. Expression analysis revealed that CoRNS6 is expressed exclusively in the ovary; CoRNS5 is expressed at the highest level in the style, followed by lower levels in the petals, anthers, filaments, receptacle, and ovary; CoRNS1 is expressed in all tissues except anthers; and the other genes are expressed across various floral tissues. Ex vitro pollen culture system experiments demonstrated that the CoRNS1 and CoRNS5 recombinant proteins significantly inhibited the elongated growth of autogamous pollen tubes, whereas CoRNS7 significantly reduced the pollen germination rate. Fluorescence labeling revealed that treatment of autogamous pollen tubes with the recombinant proteins CoRNS1, CoRNS5, and CoRNS7 induced microfilament skeleton depolymerization and increased the Ca²⁺ concentration within the pollen tubes. Additionally, treatment with the CoRNS5 recombinant protein increased the reactive oxygen species (ROS) levels in autogamous pollen tubes. These findings suggest that RNase T2 family genes are involved in the self-incompatibility response in C. oleifera, with CoRNS1, CoRNS5, and CoRNS7 playing pivotal roles. Overall, our results not only offer a theoretical foundation for elucidating the regulatory network governing self-incompatibility in C. oleifera, but also furnish valuable genetic resources for future molecular breeding programs targeting improved self-compatibility and increased fruit yield. Full article

Rice is highly vulnerable to concurrent drought-heat stress, which intensifies the disruption of plant growth and can cause high seedling mortality. Limited genetic diversity further constrains breeding for combined stress adaptation. Thus, mutation breeding has emerged as a solution for inducing beneficial variability in rice genomes. Based on this solution, this study aimed to identify rice mutants tolerant to drought and heat through artificial screening combined with multi-trait index analysis. Experiments were conducted from April to August 2025 at Hasanuddin University in two sequential phases: seedling screening in a controlled stress chamber and pot evaluation under semi-controlled conditions. Mutants were derived from the seeds of the double haploid (DH) rice line HS1-28-1-5, which was previously developed through anther culture and exhibited potential abiotic stress adaptability. DH seeds were exposed to gamma irradiation (200–1000 Gy) as the M1 population. Based on radiosensitivity evaluation, 200 and 400 Gy were selected and used in the present study as the M2 populations. Rice M2 evaluation results indicated that 200 Gy irradiation enhanced phenotypic variability with improved performance, whereas M2 400 Gy resulted in broader but less stable variation. Yield components were strongly associated with weight per clump, with panicle length being the primary direct contributor and weight per panicle mediating indirect effects. Principal component analysis accounted for 89.13% of the total variation, which was predominantly driven by yield traits. Integrated weighted average absolute score–tolerance score analysis classified genotypes into tolerance groups, identifying 33 putative tolerant mutants, with M2 200 Gy mutants demonstrating superior adaptability to drought-heat stress. These findings suggest that moderate irradiation coupled with multi-trait index selection provides a reproducible framework for identifying putative drought-heat-tolerant rice candidates at early stages while retaining relevance to subsequent yield recovery. Full article

Wheat anther culture-mediated embryogenesis is strongly influenced by genotype responsiveness and remains limited by low embryo-like structure (ELS) conversion efficiency, frequent albino formation, and unstable developmental progression. In this study, the effects of DNA methylation inhibitors (5-azacytidine (AZC), 5-aza-2′-deoxycytidine (DEC), and zebularine (ZEB)) and the histone deacetylase inhibitor trichostatin A (TSA) on ELS induction, ELS conversion into green regenerants (GRs), albino frequency, and spontaneous genome doubling were evaluated in wheat anther cultures with contrasting embryogenic responsiveness. The results revealed strong genotype-dependent responses to treatments with epigenetic inhibitors. The spring wheat cultivar AC Abbey showed the highest overall anther culture response, whereas winter wheat genotypes displayed limited and variable ELS conversion competence. ELS formation was observed even in recalcitrant genotypes but was not consistently associated with efficient ELS conversion into GR. Multivariate analyses indicated stronger genotype differentiation at the conversion stage than during ELS induction, suggesting that this stage represents a major bottleneck in wheat anther culture-mediated embryogenesis. Among the tested compounds, AZC and TSA most effectively stimulated ELS induction, while AZC was associated with the lowest albino frequency. DEC showed the highest proportion of spontaneous doubled haploids. Overall, treatment with epigenetic inhibitors may enhance ELS induction but does not overcome genotype-dependent recalcitrance at the conversion stage under the applied anther culture conditions. Full article

This study aimed to develop an anther culture protocol for triticale (×Triticosecale Wittmack) and generate a doubled haploid (DH) population combining awnlessness and stripe rust resistance. A wheat anther culture protocol was evaluated on nine triticale varieties, with and without Trichostatin A (TSA), and tested on parental genotypes—an awned, stripe rust–resistant breeding line (AT-45) and an awnless variety (‘1143’)—as well as on ten F₁ plants derived from crosses between AT-45 and ‘1143’. Plant regeneration varied widely among varieties, ranging from 0.8 to 39.7 green plants per 30 anthers (1.6–80 per spike), with an overall mean of 9.9 (20 per spike). TSA did not significantly improve green plant production in this study, though further optimisation of the application method may be warranted. An average of 17.4 green plants per spike was obtained from the F₁ plants, and 1130 regenerant plants were grown to maturity, with a mean spontaneous chromosome doubling rate of 42.5%. A total of 480 DH lines were harvested, comprising 250 awned, 60 reduced awn, and 170 awnless lines. Awned and reduced awn lines were discarded, and 114 awnless lines were advanced for field evaluation of stripe rust resistance and agronomic traits. These results establish an effective anther culture system for DH production in triticale and demonstrate the potential of DH technology to accelerate the development of resilient, high-performing varieties. Full article

Husk tomato (Physalis ixocarpa Brot.) is a crop of major economic, cultural, and nutritional importance in Mexico and exhibits substantial genetic and morphological diversity. Characterizing this variability is essential for both germplasm conservation and breeding programs. During the spring–summer 2024 growing season, 28 husk tomato populations were evaluated at the Bajío Experimental Station (INIFAP), Guanajuato, Mexico, using a completely randomized design with 12 replications. Forty-one traits were assessed following UPOV and IPGRI descriptors. Cluster analysis, canonical discriminant analysis, and the ESIM selection index were applied. A total of 77 morphotypes were identified, exhibiting variation in 33 of the 41 evaluated traits, mainly related to growth habit, leaf morphology, fruit traits, and calyx attributes. Correspondence analysis revealed a close relationship between vegetative growth and fruit size. Cluster analysis clustered the morphotypes into six clusters with no clear geographic structure, suggesting extensive gene flow. Canonical discriminant analysis explained 94.65% of the total variation, identifying seed size, leaf dimensions, and number of anthers as key discriminant traits. The ESIM index highlighted six morphotypes with favorable agronomic and morphological combinations. These results provide a practical basis for the selection of parental materials in husk tomato breeding programs under diverse agroecological conditions. Full article

Anther-derived somatic embryogenesis is a valuable approach in rubber tree (Hevea brasiliensis) breeding; however, its effectiveness is highly influenced by the developmental stage of the microspores. The present investigation focused on male flower buds of the cultivar Reyan 73397 at successive developmental stages to examine the relationship between visible bud characteristics and internal microspore development, assess how microspore developmental stage affects callus induction and somatic embryo formation, and identify the stage with the greatest embryogenic potential. Cytological observations distinguished six well-defined phases of microspore development, spanning from microspore mother cells to fully mature pollen grains, each reliably linked to particular bud diameters, coloration, and anther morphology. Anthers corresponding to each developmental phase were cultured in vitro, and their ability to initiate callus and produce somatic embryos was systematically evaluated. Anthers containing uninucleate microspores exhibited the highest rates of both callus formation and somatic embryogenesis, with the early-uninucleate stage showing the strongest response. This stage consistently matched flower buds measuring 1.42–1.57 mm in transverse diameter and displaying a green to yellowish-green appearance. In contrast, anthers collected at the microspore mother cell and tetrad stages did not produce embryogenic responses. Histological evidence has indicated that both callus and somatic embryos originate from diploid somatic tissues of the anther wall, particularly connective parenchyma cells, rather than from microspores themselves. Based on these findings, a rapid, non-destructive selection method integrating bud diameter, bud color, and sieve-based size separation was developed to identify responsive explants efficiently. Overall, this study defines the optimal developmental window for anther culture in rubber trees, verifies the somatic origin of embryogenic tissues, and provides a practical morphological and cytological basis for improving anther culture efficiency in rubber tree breeding programs. Full article

Shoot tip culture is currently the most widely used method for strawberry virus elimination, yet its efficiency has approached the theoretical limit of 80–85%. While anther culture offers a higher virus-free rate, it faces the technical bottleneck of low callus differentiation rates. To address this issue, this study used ‘Miaoxiang 7’ strawberry anthers as explants and systematically optimized key culture parameters. Different combinations of cytokinins and auxins were tested across various culture stages—including callus induction, adventitious bud differentiation from callus, proliferation, and rooting—to determine the most efficient plant growth regulator (PGR) formulations. This approach enhanced both the callus induction rate and differentiation efficiency. The regenerated plants obtained in this study achieved a virus-free rate of 98.39%. Flow cytometric ploidy analysis revealed that octoploids constituted the highest proportion, reaching 73.64%, among the regenerated plants. SSR molecular marker analysis indicated a genetic similarity coefficient of 0.9778–1.0000 between the regenerated plants and the maternal parent. Virus-free treatment holds potential for enhancing physiological growth indicators and fruit quality, demonstrating advantages in certain key metrics such as leaf area and soluble solids content. This technological system provides a viable approach for obtaining virus-free plants through anther culture, overcoming the technical limitation of low callus differentiation rates in anther culture. It offers reliable technical support for the sustainable development of the strawberry industry. Full article

Conventional rice breeding predominantly relies on hybridization techniques, with hybrid progenies typically requiring 8 to 10 generations of selfing to achieve genetically stable homozygous lines. In contrast, haploid breeding enables the derivation of stable doubled haploid (DH) lines from hybrid progeny in just one generation, substantially shortening the breeding cycle. Haploid breeding comprises two core steps: haploid induction and chromosome doubling, with efficient haploid induction being pivotal to the success of this technology. Currently, anther culture, due to its relatively mature and stable protocol, has become the primary method for obtaining haploids in rice haploid breeding. This review systematically summarizes the research progress in rice anther culture, focusing on the fundamental steps and applications of haploid breeding, the developmental history of anther culture, factors influencing anther culture efficiency and their underlying genetic mechanisms, current challenges and potential countermeasures, and future prospects for rice anther culture technology. 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

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

The anther culture-based breeding of rice is a plant tissue culture technique that utilizes rice pollen to rapidly obtain haploid plants. In comparison with traditional breeding methods, this technique shortens the breeding cycle and enables the quick generation of homozygous plants, which is of great significance for the development of new rice varieties and the expansion of germplasm resources. With the advancement of technologies, the use of the anther culture technique in rice breeding has matured and has been applied to the development and utilization of new varieties with high yield, multiple resistances, and superior quality, in combination with other breeding methods. This technique has gained widespread attention globally, with many countries adopting it to create new germplasm resources. This study reviews advances in the rice anther culture technique, the factors influencing anther culture efficiency, and the progress in breeding rice varieties using this technique, as well as analyzes the current challenges and future prospects of anther culture breeding. Full article

In vitro anther culture is a technique used to produce haploid plants when regenerating varieties with specific traits. To generate haploid plants with preferred characteristics, an anther culture technique was established for Lilium longiflorum “Show Up”. Morphological characteristics were recorded, including the flower bud length and anther color corresponding to different stages of microspore development. The effects of different flower bud lengths, various concentrations of exogenous plant growth regulators (PGRs), low-temperature pretreatment at 4 °C, and incubation under dark conditions on the induction of callus formation were studied. When the flower buds were 2.2–2.4 cm in length and the microspores were in the mononuclear development phase, callus induction reached the highest rate (15.6%). Callus was not induced when the PGRs 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KT) were added separately to the growth medium, but the highest callus induction rate occurred when anthers were cultured on the medium containing 2,4-D (0.75–1.0 mg/L) and KT (4 mg/L). The low-temperature pretreatment significantly enhanced the induction rate of anthers, but prolonged low-temperature pretreatment reduced the induction rate. The optimal period of cultivation in darkness was 6 d. After 15 days of cultivation, the number of swollen anthers was recorded, and these were transferred onto the differentiation medium Murashige and Skoog (MS) + 1-naphthaleneacetic acid (NAA) (2.0 mg/L), sucrose (30 g/L), and agar (7 g/L) at pH 5.8, whereon 100% differentiation was recorded. Overall, 14 regenerated lines were obtained by in vitro anther culture. Chromosome ploidy was determined by counting chromosomes in the root tips of ten regenerated plants, and four were found to be haploids. This study lays the foundation for anther culture in lilies to shorten the breeding cycle, improve selection efficiency, facilitate efficient genetic transformation, and enable the effective production of both haploid and double-haploid plants. Full article

Cucumber mosaic virus (CMV) is one of the most dangerous viral diseases threatening Solanaceae crops, in particular Capsicum sp. This study aims to develop double haploid (DH) pepper lines from germplasm resistant to CMV in order to speed up the breeding process. For this purpose, six genotypes previously tested for CMV resistance were used. Two induction mediums (17-2 and 17-3) with different concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) for anther incubation and further plant regeneration were applied. L10 was the most responsive genotype, exhibiting the highest direct embryogenesis and the most plant regenerants on both mediums. Medium-specific response was observed in genotype L9 where regenerants were observed only on 17-2. Further, eight DH lines were evaluated with two CMV isolates (L-BG and PV-0418) and checked for local and systemic presence of the pathogen in leaves and fruits for a period of 60 days by DAS-ELISA. Of the tested DH lines, four (DH2, DH6, DH7 and DH9) were resistant to both strains, two (DH5 and DH14) were resistant to L-BG, and two (DH19 and DH21) were susceptible to both isolates. Field evaluation of DH7, DH9, and DH14 for some agronomic and morphological traits divided them into two groups according to the original genotypes. Full article

Hop latent viroid (HLVd), a 256-nucleotide RNA strand with complementary base-pairing and internal stem loop structures, forms circular or rod-shaped molecules within diseased plants. RT-PCR/RT-qPCR was used to assess HLVd transmission, spread and longevity. The viroid was detected in asymptomatic stock plants and in rooted vegetative cuttings, as well as in recirculated nutrient solution sampled from propagation tables and nozzles. Plant-to-plant spread through root infection in hydroponic cultivation was demonstrated. The viroid survived for 7 days and 4 weeks, respectively, in crushed leaf extracts (sap) or dried leaves/roots at room temperature. Following stem inoculation with infectious sap, HLVd was detected in root tissues within 2–3 weeks and in the foliage within 4–6 weeks. Plants grown under a 12:12 h photoperiod to induce inflorescence development showed more rapid spread of HLVd compared to 24 h lighting. The viroid was subsequently detected in inflorescence tissues, in trichome glands, in dried cannabis flowers and in crude resinous oil extracts. Anthers and pollen from infected male plants and seeds from infected female plants contained HLVd, giving rise to up to 100% infected seedlings. Artificially inoculated tomato and tobacco plants supported viroid replication in roots and leaves. Infected cannabis leaf and root tissues treated with UV-C for 3–5 min or temperatures of 70–90 °C for 30 min contained amplifiable HLVd-RNA. Infectious plant extract treated with 5–10% bleach (0.825% NaOCl) or 1000 ppm hypochlorous acid yielded no RT-PCR bands, suggesting the RNA was degraded. Meristem tip culture from HLVd-infected plants yielded a high frequency of pathogen-free plants, depending on the genotype. Full article

Lonicera japonica Thunb has significant edible and medicinal value, possessing heat clearing, detoxification, antibacterial, and blood pressure reduction properties. Currently, its quality is constrained by factors such as climate, environment, flowering period, and germplasm degradation. The strategy of using bioreactors and abiotic inducers to produce bioactive metabolites has not yet been implemented. This study reports, for the first time, the induction of an embryogenic callus from L. japonica anthers, the identification of tissue morphological structures, and the effects of light induction on the callus morphology, metabolite accumulation, and antioxidant activity. The results showed that the MS medium, supplemented with 1.0 mg·L⁻¹ 6-BA, 1.5 mg·L⁻¹ NAA, 1.5 mg·L⁻¹ 2,4-D, and 0.2 mg·L⁻¹ KT, induced 89% embryogenic callus formation. Uniform callus lines were obtained using 2.0 mg·L⁻¹ 6-BA, 0.5 mg·L⁻¹ NAA, and 0.2 mg·L⁻¹ KT in each subcultivation. Embryogenic cells were observed to have closely arranged spherical protruding granules on their surface, along with visible nuclei and numerous starch grains. After 15 days of blue light induction, active metabolites and antioxidant activities peaked. This experimental system not only provides support for germplasm innovation but also indicates that abiotic inducers can be utilized as a means to achieve higher yields of metabolic products. Full article