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Background: This study aimed to produce Odontoglossum ringspot virus (ORSV)-free Cymbidium orchid 'New True' plants from ORSV-infected mother plants by culturing their meristems and successively repeating subcultures of protocorm-like bodies (PLBs) derived from the meristems. Results: Initially, ORSV was confirmed as the causative agent of viral symptoms in orchid leaves via reverse transcription-polymerase chain reaction (RT-PCR) analysis. Meristems from infected plants were cultured to generate PLBs, which in sequence were repeatedly subcultured up to four times. RT-PCR and quantitative RT-PCR analyses revealed that while ORSV was undetectable in shoots derived from the first subculture, complete elimination of the virus required at least a second subculture. Genetic analysis using inter-simple sequence repeat markers indicated no somaclonal variation between regenerated plants and the mother plant, suggesting that genetic consistency was maintained. Conclusion: Overall, our findings demonstrate that subculturing PLBs for a second time is ideal for producing genetically stable, ORSV-free Cymbidium orchids, thus offering a practical means of generating genetically stable, virus-free plants and enhancing plant health and quality in the orchid industry. [ABSTRACT FROM AUTHOR]

Background: Microspore embryogenesis is a process that produces doubled haploids in tissue culture environments and is widely used in cereal plants. The efficient production of green regenerants requires stresses that could be sensed at the level of glycolysis, followed by the Krebs cycle and electron transfer chain. The latter can be affected by Cu(II) ion concentration in the induction media acting as cofactors of biochemical reactions, indirectly influencing the production of glutathione (GSH) and S-adenosyl-L-methionine (SAM) and thereby affecting epigenetic mechanisms involving DNA methylation (demethylation—DM, de novo methylation—DNM). The conclusions mentioned were acquired from research on triticale regenerants, but there is no similar research on barley. In this way, the study looks at how DNM, DM, Cu(II), SAM, GSH, and β-glucan affect the ability of green plant regeneration efficiency (GPRE). Results: The experiment involved spring barley regenerants obtained through anther culture. Nine variants (trials) of induction media were created by adding copper (CuSO4: 0.1; 5; 10 µM) and silver salts (AgNO3: 0; 10; 60 µM), with varying incubation times for the anthers (21, 28, and 35 days). Changes in DNA methylation were estimated using the DArTseqMet molecular marker method, which also detects cytosine methylation. Phenotype variability in β-glucans, SAM and GSH induced by the nutrient treatments was assessed using tentative assignments based on the Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The effectiveness of green plant regeneration ranged from 0.1 to 2.91 plants per 100 plated anthers. The level of demethylation ranged from 7.61 to 32.29, while de novo methylation reached values ranging from 6.83 to 32.27. The paper demonstrates that the samples from specific in vitro conditions (trials) formed tight groups linked to the factors contributing to the two main components responsible for 55.05% of the variance (to the first component DNM, DM, to the second component GSH, β-glucans, Cu(II), GPRE). Conclusions: We can conclude that in vitro tissue culture conditions affect biochemical levels, DNA methylation changes, and GPRE. Increasing Cu(II) concentration in the IM impacts the metabolism and DNA methylation, elevating GPRE. Thus, changing Cu(II) concentration in the IM is fair to expect to boost GPRE. [ABSTRACT FROM AUTHOR]

Floristic composition, population structure, and regeneration status of woody species of Dabal forest found in East Hararghe zone of Oromia Regional State, Ethiopia, were studied. Vegetation data were obtained from 52 main plots of 20 × 20 m for mature woody species and 5 subplots of 5 × 5 m for seedlings and saplings. Density and dbh of each live woody plant species found in each sample plot were recorded. Frequency, basal area, importance value, and Shannon–Wiener diversity indices were also computed. Totally 59 woody plant species distributed in 33 families were documented. Of these, 45.80, 44.10, and 5.08% were shrubs, trees, and lianas, respectively. Species diversity and evenness indices were 3.56 and 0.87, respectively. Stem count of all woody species was 3379 stems ha−1. Out of this, 44.6, 30.8, and 24.59% were seedlings (dbh <3.5 cm), saplings (dbh between 3.5 and 10 cm), and mature (dbh >10 cm) individuals, respectively. Total basal area of all individuals with dbh ≥3.5 cm was 29.88 m2 ha−1. Juniperus procera, Cupressus lusitanica, Eucalyptus globulus, Afrocarpus falcatus, Eucalyptus camaldulensis, Myrsine africana, Maytenus undata, Hagenia abyssinica, Ekebergia capensis, and Cordia africana were species with top ten IVI. Most of these species were top densest, dominant, and frequent. Analysis of population structure based on pooled densities of all species in each dbh class showed that density of seedling > sapling > mature individuals, signifying healthy population structure with good natural regeneration potential. On individual basis, however, 35.6 and 8.5% of species showed fair and poor regeneration statuses, respectively, that deserve attention for conservation. [ABSTRACT FROM AUTHOR]

The frequency of severe wildfires is on the rise in the Mediterranean Basin as a result of climate change and land abandonment. Recurrent wildfires may retard or impede ecosystem recovery, frequently requiring the implementation of restoration practices. In that context, a post‐fire deer exclusion experiment was conducted in a Mediterranean mixed forest ecosystem with high population densities of deer species (Fallow deer and Red deer). A deer exclusion area was established as a form of restoration intervention to promote post‐fire vegetation recovery. We surveyed plant species during the second and third springs after fire in both deer‐excluded and deer‐allowed areas in order to detect changes in the community. We analyzed the plant species composition, species diversity, and structure of herbaceous and woody plant communities. We also compared the frequency of annual and perennial herb species, functional groups, and post‐fire plant regeneration strategies. The main differences were due to differences between springs rather than of deer‐excluded and deer‐allowed plots. Deer consumed both woody and herbaceous species, favoring the assemblage of herbaceous over woody species. Deer favored the establishment of annual forbs, including unpalatable and/or exotic species, while limiting the abundance of graminoids. Observed deer impacts could have been magnified during the second spring by a drought. Our study demonstrates that deer exclusion can be an effective restoration practice for promoting post‐fire herbaceous regeneration in forests with significant densities of wild ungulates, although seasonal effects may override restoration practice effects. [ABSTRACT FROM AUTHOR]

The forest microclimate shapes many aspects of forest functioning, including plant regeneration and wildfire occurrence. In complex landscapes with varying terrain, the forest microclimate varies at fine spatial scales (10–100 m2). However, accurately mapping this variation remains challenging. Vapor pressure deficit (VPD) is an important microclimatic variable for plant growth and fire activity, yet few studies have specifically focused on downscaling VPD. The aim of this study was to examine the drivers of in-forest VPD in temperate eucalypt forests and develop a model to predict in-forest VPD. We use microclimate data from 37 in-forest weather stations, installed across an aridity gradient in southeastern Australia. We used linear mixed models within an information theoretic approach to develop a predictive model for daily maximum in-forest VPD using open VPD and topographic variables. The highest-ranked model included fundamental topographic drivers of vegetation structure and microclimate in forested landscapes: aspect, elevation, and slope, in addition to open VPD. The model had high accuracy when tested against independent data. We used this model to map fine-scale (30 m2, daily) maximum in-forest VPD across a topographically complex case study landscape. Predicted in-forest VPD showed considerable spatial and temporal variations not captured by coarse-scale open VPD. This represents a significant advancement in our ability to model microclimatic conditions in temperate eucalypt forests and has the potential to advance our understanding of how ecosystem processes vary at fine spatial scales. [ABSTRACT FROM AUTHOR]

In plant tissue culture, differences in endogenous levels of species-specific plant growth regulators (PGRs) may explain differences in regenerative capacity. In the case of polyamines (PAs), their dynamics and distribution may vary between species, genotypes, tissues, and developmental pathways, such as sexual reproduction and apomixis. In this study, for the first time, we aimed to assess the impact of varying endogenous PAs levels in seeds from distinct reproductive modes in Miconia spp. (Melastomataceae), on their in vitro regenerative capacity. We quantified the free PAs endogenous content in seeds of Miconia australis (obligate apomictic), Miconia hyemalis (facultative apomictic), and Miconia sellowiana (sexual) and evaluated their in vitro regenerative potential in WPM culture medium supplemented with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The morphogenic responses were characterized by light microscopy and scanning electron microscopy and discussed regarding the endogenous PAs profiles found. Seeds of M. sellowiana presented approximately eight times more putrescine than M. australis, which was associated with a higher percentage of regenerated calluses (76.67%) than M. australis (5.56%). On the other hand, spermine levels were significantly higher in M. australis. Spermine is indicated as an inhibitor of auxin-carrying gene expression, which may have contributed to its lower regenerative capacity under the tested conditions. These findings provide important insights into in vitro morphogenesis mechanisms in Miconia and highlight the significance of endogenous PA levels in plant regeneration. These discoveries can potentially optimize future regeneration protocols in Miconia, a plant group still underexplored in this area. [ABSTRACT FROM AUTHOR]

The Agrobacterium-based transgenic technique is commonly used for gene function validation and molecular breeding. However, it is not suitable for plants with a low regeneration capacity or a low transformation rate, such as Panax notoginseng (Burk) F.H. Chen and Lilium regale Wilson. In this study, a novel Agrobacterium transformation method based on injection in the meristems was developed using P. notoginseng and L. regale as experimental models. PCR analysis confirmed the successful integration of the reporter gene DsRed2 (Discosoma striata red fluorescence protein 2) into the genome of two experimental models. QRT-PCR and Western blot analysis demonstrated the transcriptional and translational expression of DsRed2. Additionally, laser confocal microscopy confirmed the significant accumulation of the red fluorescent protein in the leaves, stems, and roots of transformed P. notoginseng and L. regale. Most importantly, in the second year after injection, the specific bright orange fluorescence from DsRed2 expression was observed in the transgenic P. notoginseng and L. regale plants. This study establishes a fast, efficient, and tissue-culture-independent transgenic technique suitable for plants with a low regeneration capacity or a low transformation rate. This technique may improve the functional genomics of important medicinal and ornamental plants such as P. notoginseng and L. regale, as well as their molecular breeding. [ABSTRACT FROM AUTHOR]

Santalum album is a hemiparasitic evergreen tree known for its heartwood oil, widely used in the cosmetics and aromatherapy industry. Overexploitation in the past few decades has led to the classification of this species as Vulnerable on the IUCN Red List of Threatened Species. Drupes of S. album are single-seeded and usually monoembryonic in nature, producing normal seedlings. However, in a previous study, we also observed some polyembryonic seeds. In this news article we share our polyembryony findings from Marayoor population as well as the growth and survival of seedlings which emerged from polyembryonic seeds. We found that less than 1% of the seeds in Marayoor population exhibited polyembryony (duplets). The general trend was that one radicle emerged 2-3 days earlier than the other and grew faster and healthier compared to the radicle from monoembryonic seeds. The second (smaller) seedling from polyembryonic seeds began to degenerate if not separated, but it survived well (albeit with low growth potential) once transplanted into a separate polybag. In S. album, polyembryony does not seems to be an essential ecological competitive strategy, unlike in several invasive species. For mass-scale seedling production of this vulnerable species, we recommend separating twin seedlings soon after their emergence for a better survival rate. [ABSTRACT FROM AUTHOR]

Throughout eastern North America, chronic white-tailed deer overbrowsing and widespread exotic plant invasions degrade native plant diversity and abundance. However, because deer densities are high across entire regions, it is challenging to find large areas where deer have been at low density for long periods. We predicted native plant diversity and abundance would be significantly higher during gap-phase regeneration where deer have been maintained at low densities (~ 7 deer/km²) compared to where deer have been chronically overabundant. Simultaneously, we predicted that exotic plant diversity and abundance would be lower in gaps where deer have been maintained at low versus high densities. We also evaluated whether deer density interacts with gap age, gap size, and gaps in dry versus more mesic forest patches. We studied 41 gaps throughout an 88 km2 fenced military post where deer were maintained near pre-European-settlement densities for 67 years and in nearby forests where deer have been overabundant for decades. Native species richness, diversity, and cover were 37–65% higher, and exotic species cover was 80% lower in canopy gaps at low relative to high deer density. Stem height and density of multiple native canopy tree species (e.g., two Quercus spp.) were 5-20-fold higher within canopy gaps at low deer density. Moreover, 10 native woody species were indicators of low deer density, including three Quercus species, whereas no native woody species were indicators of high deer density. Deer were the primary filter underlying these different patterns in diversity, abundance, and plant height. Our findings demonstrate that gaps develop a vigorous and diverse native sapling layer, with far fewer exotics, in areas of low deer density without a history of chronic overbrowsing. We propose that military posts may be conservation and native plant regeneration hotspots wherever they regularly cull deer. [ABSTRACT FROM AUTHOR]

Oryza sativa ssp. indica is not amenable to genetic modifications owing to its recalcitrant nature, rendering it difficult to transform and recover improved varieties to combat the persisting biotic and abiotic stress conditions. Therefore, in the present study, we have attempted to enhance transformation efficiency by applying polyamines and vacuum infiltration in Agrobacterium tumefaciens-mediated genetic transformation of Indica rice cv. IR64 seed-derived embryogenic calli. The highest number of regenerating calli, with maximum number of shoots per callus, was achieved in regeneration medium supplemented with 0.2 mM Spermidine, and the regenerated shoots displayed improved rooting when cultured on MS medium supplemented with 0.1 mM Putrescine. Further, vacuum infiltration of calli for 4 min resulted in the highest transformation efficiency of 8.1% as evident by GUS positive calli. The transformed calli were screened on the selection medium supplemented with hygromycin, and the integration and expression of the T-DNA in the rice genome were confirmed by GUS histochemical assay, PCR and Southern hybridization. The outcome of this study would be useful in micropropagation and genetic transformation studies of recalcitrant rice varieties. [ABSTRACT FROM AUTHOR]

This study investigates the effects of seasonal changes in vegetation productivity on olive baboon feeding behavior in a protected Guinea savannah (Kainji Lake National Park). Over two consecutive years (2017 and 2018), observations were conducted both during the wet and dry seasons using a scan sampling method. Results revealed that olive baboons consumed 34 plant species belonging to 20 families, with 28 species in the wet season and 12 in the dry season. A total of 922 feeding events were recorded in the wet season and 621 in the dry season, indicating significant seasonal variation. Fruits were the preferred food item, especially in the dry season, followed by animal matter, seeds, leaves, and subterranean food. Interestingly, baboons also consumed tree bark regardless of season. In addition, their consumption of fruits (in both seasons) and seeds (in the dry season) highlights their ecological role in seed dispersal and plant regeneration within the park. To sustain baboon (and all non-human primates) conservation efforts within the park, it’s important to maintain a high diversity and abundance of native fruit trees throughout the year. This study highlights the importance of understanding how seasonal changes in vegetation affect olive baboon feeding behavior for effective park management and biodiversity conservation. [ABSTRACT FROM AUTHOR]

This document is an editorial from the International Journal of Molecular Sciences discussing recent advances in plant somatic embryogenesis. Somatic embryogenesis is a process in which somatic cells undergo changes to form structures called somatic embryos, which can develop into plants. The article explores the applications of somatic embryogenesis in clonal propagation, genetic modification, and plant genome editing. It also discusses the use of somatic embryos in cryopreservation and the study of molecular mechanisms in plant development. The editorial highlights various studies on the induction of somatic embryogenesis, the role of transcription factors, the influence of auxins, and the practical applications of somatic embryogenesis in forest management and breeding programs. The authors conclude that while somatic embryogenesis is a powerful tool in plant biotechnology, further interdisciplinary research is needed to address remaining challenges. [Extracted from the article]

Background: Astragalus membranaceus Mongholicus (Astragalus) is one of the most widely used medicinal plants in the world. It is a traditional Chinese medicine plant that has been used to treat various human diseases and conditions, such as inflammation, gastrointestinal bacterial infections and malignant tumors. With the expansion of artificial planting areas, the demand for high-quality Astragalus seedlings is also increasing. The traditional seedling-raising methods of direct seeding and induced callus have problems such as a long growth period, unstable genetic traits, strict sampling and rooting difficulties. Therefore, it is very important to multiply the excellent germplasm by optimizing the tissue culture regeneration system. Methods: In this study, Astragalus field cultivated plants, which are easily available, were used as materials and the method of tissue culture cuttings was used to select the direct inoculation method of stem segments as explant materials to establish a plant regeneration system of Astragalus and the best sampling period, sampling site and optimal medium for regeneration of field cultivated plants were screened. Result: The best sampling period for plant regeneration of Astragalus in the field was about 40 d after the emergence of the 3-yearold Astragalus and the rooting rate of the regenerated plants was 100.00%. The best sampling site is the middle section of the stem and the regeneration system using the middle section of the stem as the explant is better than using the top and bottom of the stem as the explant and the rooting rate of the regenerated plants is 100.00%; the best medium for the regenerated plants is N22: 1/2MS+1 mg/L NAA and T28: 1/2MS+1 mg/L ABT, the rooting rates were 76.67% and 96.67%, respectively. The regenerated plants established with the stems of the field cultivated plants of Astragalus as explants were all able to induce seedlings after 1 week and the regenerated seedlings start to take root after 3 weeks of growth and can be transplanted and propagated after 6 weeks of culture. The regeneration system established in this study by direct cuttings from cultivated Astragalus stems is more rapid and efficient, breaking through the difficulties of limited access to material and long growth period of regenerated seedlings in the traditional regeneration system and providing technical support for the conservation and utilization of wild resources of Astragalus and rapid expansion of new varieties and germplasm conservation. [ABSTRACT FROM AUTHOR]

An efficient and reproducible in vitro regeneration protocol was developed for elite cotton cultivar KC3 by using plant growth regulators (PGRs) in combination with seaweed polysaccharide (SP) extracts. The existence of polysaccharide in seaweed extract was confirmed by Fourier transform infrared spectroscopy (FT-IR) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy analysis. The extracted SP extract efficacy was tested for in vitro plant regeneration. The maximum callus frequency (89.4%) was obtained from hypocotyl explant in the Murashige and Skoog (MS) medium supplemented with 4.0% glucose, 1.5 mg L−1 thidiazuron (TDZ), 0.6 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D), and 30.0 mg L−1 SP. Remarkably, PGR- and SP-fortified medium inhibits the phenolic excretion from the explants. The well-developed yellow green friable texture of callus was transferred to shoot initiation medium. MS medium fortified with 4.0% glucose, 2.0 mg L−1 6-(γ,γ-dimethylallylamino) purine (2iP), 1.0 mg L−1 kinetin (KIN), 1.0 mg L−1 6-benzylaminopurine (BA), and 40.0 mg L−1 SP has shown maximum response (85.2%), and it produced 9.5 shoots per callus. The elongated shoots were cultured on root induction medium which consists of Murashige and Skoog (MS) salts with indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 1-naphthaleneacetic acid (NAA), and SP. The results revealed that the maximum number of roots (12.9 per shoot) with 8.6 cm in length was achieved on MS medium supplemented with 0.6 mg L−1 IBA, combined with 30.0 mg L−1 SP. Therefore, modified MS medium with natural bio-stimulant has more potential and is more reliable for in vitro regeneration of plants by neutralizing the effects of phenolic compounds secreted by the explants. [ABSTRACT FROM AUTHOR]

Eucommia ulmoides Oliver (E. ulmoides) is rich in a variety of medicinally active compounds which have a very high economic value. Various types of explants (stem, stem with axillary bud, terminal bud, and leaves) were cultured on Murashige and Skoog (MS) medium with different types and concentrations of growth regulators. The present study found that the cultured stem explants induced callus. Terminal bud and the stem with axillary bud–cultured explants induced clustered regenerated plantlets. The terminal bud was designated as clustered regenerated plantlets I after culture, while the stem with axillary bud was labeled as clustered regenerated plantlets II after culture. The highest induction rate of clustered regenerated plantlets was 66.67% after culture on medium supplemented with 0.5 mg ּL−1 6-benzylaminopurine (6-BA) and 0.01 mg ּL−1 α-naphthaleneacetic acid (NAA). The highest induction rate of callus tissue was 80.66% following culture on medium containing 0.09 mg ּL−1 NAA and 0.5 mg ּL−1 6-BA. The medicinal active ingredients of clustered regenerated plantlets and callus tissue were compared with those in natural seedlings and demonstrated that there was little difference in the types of compounds between clustered regenerated plantlets and natural seedlings. The contents of phenylpropanoids, phenols, flavonoids, lignin, and iridoids in different induced tissues were determined and showed that the best material for obtaining lignin compounds was clustered regenerated plantlets induced by terminal bud, and the best material for obtaining phenylpropanoids, phenols, and iridoids was clustered regenerated plantlets induced by stems with axillary bud. The theoretical basis and technical support provided in this study are essential for the establishment of an asexual propagation system for E. ulmoides and the commercial regeneration of plants. Furthermore, in vitro culture can efficiently produce a significant amount of medicinally active components, thereby decreasing reliance on wild resources. Research on the variations of medicinal components in E. ulmoides not only offers a theoretical foundation but also supplies experimental materials for the development of novel drugs. [ABSTRACT FROM AUTHOR]

Paspalum notatum Flüggé is a subtropical grass native from the Americas and one of the main components of the subtropical South American grasslands. Although P. notatum exhibits a high forage productivity and persistence, some limitations are observed in the species, such as forage quality due to high lignin content. The development of efficient tissue culture and plant transformation protocols in cultivars for forage production are necessary to embrace novel genetic improvement through transgenesis and genome editing. Efficient regeneration and transformation systems for many plant species can be hampered by genotype dependency, which can only be determined through extensive laboratory testing and evaluation. In this study, various factors extracted from protocols have been evaluated to establish efficient somatic embryogenesis, plant regeneration, and genetic transformation in apomictic initial variety INIA Sepé. Optimal somatic embryogenesis and regeneration from explant sources, such as mature seeds and meristematic tissue derived from in vitro propagated tillers, ranged between 79 and 88%. Microprojectile bombardment of two plasmids encoding a constitutively regulated reporter gene and nptII selectable marker expression constructs showed an average transformation efficiency of 10.3% from meristematic tissue as an explant source. Furthermore, the constitutive promoters, 35S and ZmUbi, were tested in GFP transient expression assays to evaluate optimal cassettes for transgene(s) expression. Translation of a wheat codon–optimized Cas9 sequence using Cas9:2A:tuGFP fusion protein was also tested in protoplasts. The information generated on promoter activity and Cas9 translation, and the establishment of an efficient transformation system, provided useful tools for future work in genetic engineering and genome editing in P. notatum cv. INIA Sepé. [ABSTRACT FROM AUTHOR]

Juglans mandshurica is an important component of Korean pine mixed and secondary forests in Northeast China and is also a precious timber and economic species. In this study, plant regeneration of J. mandshurica has been established using stems with bud and mature zygotic embryos as explants. The results showed that placing the stems with buds in low-temperature conditions (0 to 4°C) and in darkness for 5 d inhibited the browning of the explants and promoted bud sprouting; Na2S2O3 also inhibited the browning of mature zygotic embryos significantly. The suitable basal media and hormones for bud sprouting and zygotic embryo germination were (1) WPM medium (woody plant medium) containing 2.0 mg·L−1 6-benzylaminopurine (6-BA) and 0.01 mg·L−1 3-indolebutyric acid (IBA) and (2) DKW medium (Driver and Kuniyuki medium) containing 2.5 mg·L−1 6-BA and 0.1 mg·L−1 IBA. The suitable basal medium and hormone for rooting of shoots from buds was 1/2 Murashige and Skoog (MS) medium (the macro-elements were half-strength of MS medium) supplemented with 1.0 mg·L−1 IBA, and the suitable basal medium and hormone for rooting of seedlings derived from zygotic embryo was 1/2 MS medium containing 1.0 mg·L−1 IBA, and DKW medium with 2.5 mg·L−1 6-BA, 0.1 mg·L−1 IBA, 0.2 mg·L−1 gibberellin A3 (GA3), and 0.2 g·L−1 activated carbon (AC). About 95% of the rooted plantlets survived after acclimation and transplantation. These results provided a foundation for the scale propagation to meet the demands of forestry production of the species. [ABSTRACT FROM AUTHOR]

Plant formation from in vitro-cultivated microspores involves a complex network of internal and environmental factors. Haploids/doubled haploids (DHs) derived from in vitro-cultured microspores are widely used in plant breeding and genetic engineering. However, the mechanism underlying the developmental switch from regular pollen maturation towards microspore-derived plant regeneration remains poorly defined. Here, RNA-sequencing was employed to elucidate the transcriptional landscapes of four early stages of microspore embryogenesis (ME) in barley cultivars Golden Promise and Igri, which exhibit contrasting responsiveness to microspore-derived plant formation. Our experiments revealed fundamental regulatory networks, specific groups of genes, and transcription factor (TF) families potentially regulating the developmental switch. We identified a set of candidate genes crucial for genotype-dependent responsiveness/recalcitrance to ME. Our high-resolution temporal transcriptome atlas provides an important resource for future functional studies on the genetic control of microspore developmental transition. [ABSTRACT FROM AUTHOR]

Yam (Dioscorea sp.) is an important staple crop for millions of smallholder farmers in West Africa. In this study, we aimed to develop an efficient indirect plant regeneration system for three important yam genotypes "Kukrupa," "Mankrong Pona" and "Matches." The potential of leaf primordia, petioles and axillary bud explants for callus induction on Murashige and Skoog (MS) medium supplemented with different concentrations (0, 3, 5, 7 and 9 mg/l) of 2,4-dicholorophenoxy acetic acid (2,4-D) or picloram were tested. Callus induction was influenced by auxin concentration as well as explant. The highest callus induction was achieved using leaf primordia ("Kukrupa" and "Mankrong Pona") explants on 3 mg/l picloram or axillary buds ("Matches") on 5 mg/l picloram. Transfer of callus to 6-benzylaminoapurine (BAP) amended medium resulted in the formation of at least two shoots per callus clump. Plantlets were obtained on basic yam medium supplemented with 0.2 mg/l 1-naphthalene acetic acid (NAA), 3 mg/l kinetin and 0.5 mg/l BAP after four weeks. Post acclimatization plantlet survival was high (75 − 82.5%). The indirect plant regeneration protocol reported through this study helps in the improvement of important yam genotypes through tissue culture-oriented genome editing, in vitro mutagenesis and also for its mass propagation. [ABSTRACT FROM AUTHOR]

Micropropagation of fig is playing an interesting role in the rapid multiplication of varieties with important characters and the regeneration of virus-free plants. FMD (Fig Mosaic Disease) is the viral disorder the most spread all over the world and considered as a serious problem for healthy fig plant propagation and high fig production. During the last four decades, many efficient protocols have been established for in vitro large-scale propagation of female figs and caprifigs for plant material sanitation. Successful micropropagation of figs using meristematic tissues (nodal segments or apical buds) is dependant to several external and internal factors including in vitro conditions (media components essentially) and ex vitro (genotype and physiological state, etc.). Specific requirements during all steps of plant regeneration, such as the initiation of in vitro cultures, shoot multiplication, plantlet rooting and acclimatization are summarized in this review. The efficacy of meristem and tip culture in the eradication of viruses from fig vitroplants is also reported. New approaches for the improvement of shoot multiplication and fig vitroplant quality (bioreactors, Arbuscular mycorrhizal fungi, etc.) and the genetic stability and conformity of micropropagated plantlets are discussed. [ABSTRACT FROM AUTHOR]

Calendula officinalis L. is an important medicinal and ornamental plant possessing multiple bioactive compounds. The in vitro plant regeneration method has recently replaced traditional field cultivation practices of calendula due to its fascinating phytochemical profile. In this study, callus formation and indirect organogenesis were described to establish an effective in vitro propagation strategy in C. officinalis. Using a gas chromatography–mass spectrometry (GC–MS) approach, the phytochemical content of tissues developed in vitro and field-grown was studied, and the biochemical contents were quantified and compared in various tissues. The incidence of callus formation from leaf explants was highest (94.44%) on MS medium fortified with 1.0 mg/L BAP and 1.0 mg/L NAA, which later became organogenic. On MS, 1.0 mg/L BAP and 1.0 mg/L NAA showed the highest indirect shoot proliferation (88.88%) efficiency. After being sub-cultured, the regenerated shootlets were cultured onto rooting medium containing different IAA/IBA concentrations; the best rooting percentage (94.44%) was achieved with 1.0 mg/L IBA. The biochemical parameters, like total phenolic content, flavonoid content, and DPPH scavenging activity, were measured. When compared to callus and field-grown developed leaf (donor) samples, all the biochemical characteristics of in vitro-produced leaf were noted to be higher. The methanolic extracts of leaf-callus and field-grown and in vitro-developed leaf tissues were subject to GC–MS-based phytocompound investigation. More than 45 therapeutically significant bioactive chemicals, like n-hexadecanoic acid, vitamin E, stigmasterol, and squalene were found in these samples. These results showed that the callus that is formed from in vitro leaf is a reliable and powerful source of several bioactive compounds with a wide range of medicinal uses. The successful stimulation of callus development, indirect organogenesis, biochemical analysis, and GC–MS confirmation of the presence of significant phytocompounds are all described in this study. This work provides a different avenue for ongoing and sustained synthesis of chemicals without endangering the surrounding ecosystem or native vegetation. [ABSTRACT FROM AUTHOR]

The regeneration of plant somatic cells is a prerequisite for their biological breeding. Identification of key genes controlling embryogenic callus (EC) differentiation and investigation of the genetic mechanism of cell fate determination are important for improving plant variety. In this study, we used the maize inbred line KN5585 and its gene-edited mutants Zmprx19-1, Zmprx19-2 and Zmprx19-3 as plant materials. Three somatic regeneration-related traits, the embryogenic callus induction rate (EIR), green callus rate (GCR) and plantlet regeneration rate (PRR), were identified by tissue culture of immature embryos. Additionally, the ECs at different differentiation stages (0 d, 5 d, 10 d and 15 d) were subjected to RNA-seq, and comparative transcriptome analyses were performed. The results showed that the somatic regeneration traits of the mutants were all highly significantly lower than those of the wild type (p < 0.01). The PRR value of KN5585 was 75.25%, while the highest PRR of the mutants was only 15.08%, indicating that knockdown of ZmPRX19 inhibited EC regeneration. Transcriptome sequencing yielded a total of 200.30 Gb of clean data from 24 libraries, with an average of 6.53 Gb of clean data per library. Mutant and wild-type gene expression data were compared separately at four differentiation stages, and 689 common differentially expressed genes (DEGs) were screened. WGCNA was used to classify these genes into nine modules, which were subsequently subjected to GO and KEGG enrichment analyses. In total, 40, 23, 17 and 5 genes were significantly (q < 0.05) enriched in plant hormone signal transduction, the MAPK signaling pathway-plant, phenylpropanoid biosynthesis and photosynthesis, respectively. Moreover, protein–protein interaction (PPI) network analysis revealed five MAPKKK17_18 hub nodes involved in the MAPK pathway-plant, which may be the key genes controlling plantlet differentiation from ECs. The above results provide a basis for the final elucidation of the molecular mechanism of plant somatic regeneration. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) deposition and native allelopathic plants may affect seed germination and growth of species through their effects on soil microbes and soil nutrient availability. However, our understanding of the interactions between N addition and allelopathic plants on the regeneration of alpine grasslands remains limited. Methods: Here, we investigated the effects of N addition and the presence of the allelopathic plant Ligularia virgaurea (Maxim.) Mattf. on seed germination, survival, and growth of native herbaceous species (Elymus nutans, Delphinium kamaonense and Tibetia himalaica) on the Qinghai-Tibet Plateau. We used piecewise structural equation modelling to assess both the direct effects of N addition, allelopathic plants, and their interactions and indirect effects mediated by soil properties, soil microbial richness and diversity, and soil enzyme activity. Results: We found that (1) L. virgaurea directly increased seed germination and early plant survival, and reduced plant root-to-shoot ratio; N addition directly increased early plant survival and biomass, (2) L. virgaurea indirectly increased plant biomass via bacterial richness, (3) N addition offsets the increase in seed germination promoted by the presence of L. virgaurea via soil acid phosphatase. Conclusion: Our study suggests the importance of direct and indirect roles of allelopathic plants, N addition and their interaction on seed germination, survival and plant growth. Our results highlight the need to consider the interactions between environmental and biological factors as well as their direct and indirect effects to obtain reliable predictions and mechanistic understanding of the response of alpine plants to future climate change. [ABSTRACT FROM AUTHOR]

This work studied the micropropagation of fegra fig (F. palmata Forssk.) during which we experienced the incidence of shoot-tip necrosis (STN). STN was evident during the shoot elongation stage, which was regenerated on Murashige and Skoog (MS) medium supplemented with 2 mg/L 6-benzylaminopurine. To alleviate SNT, we conducted a series of experiments and supplemented the medium with calcium chloride (40, 80, and 120 mg/L), ascorbic acid (50, 100, and 150 mg/L), silver nitrate (1, 2, and 3 mg/L), and boric acid (9.3, 12.4, and 15.5 mg/L). Results showed that all the treatments controlled STN at varying levels, and supplementation of medium with 3 mg/L silver nitrate reduced the incidence of STN from 80% to 24%. The regenerated shoots were rooted on the same medium with incubation of cultures in the dark for 3 weeks and subsequent 4 weeks of incubation under 16/8-hour light/dark photoperiod. The growth parameters (number of shoots and roots, length of the main shoot and root, fresh and dry weights), photosynthetic pigments (chlorophylls and carotenoids), and relative water content of plantlets were restored with the application of 3 mg/L silver nitrate to the medium. Incubation of cultures initially in the dark followed by 16/8-hour light incubation facilitated axillary shoot elongation. On the basis of our findings, it is recommended to culture the regenerated axillary shoots of fegra fig onto MS medium containing 3% sucrose, 1.5 mg/L activated charcoal, and 3 mg/L silver nitrate to manage STN effectively. [ABSTRACT FROM AUTHOR]

This article discusses the establishment of a genetic transformation system and gene editing platform for broomcorn millet using CRISPR/Cas12i.3 technology. Broomcorn millet is an ancient crop with desirable traits such as short life cycle, high photosynthetic efficiency, and tolerance to arid and saline-alkali soil. The researchers successfully developed a method for genetic transformation of broomcorn millet using Agrobacterium-mediated techniques. They also used the CRISPR/Cas12i.3 system to edit the BRACHYTIC2 (BR2) gene in broomcorn millet, resulting in dwarf plants with shorter internodes. This research has important implications for improving agronomic traits and developing new varieties of broomcorn millet. [Extracted from the article]

SUMMARY: Citrus is a model plant for studying adventitious embryos, a form of asexual reproduction controlled by a single dominant gene, RWP. This gene has been identified as the causal gene for nucellar embryogenesis, but its function has not yet been fully understood. In this study, we used the fast‐growing Fortunella hindsii as a system to explore chromatin accessibility during the nucellar embryony initiation, emphasizing elevated chromatin accessibility in polyembryonic (PO) genotypes compared to monoembryonic ones (MO). Notably, a higher level of accessible chromatin was observed in one allele of the promoter region of FhRWP, consistent with increased expression of the allele carrying the causal structural variant. By independently performing RNAi and gene editing experiments on PO genotypes, we found the downregulation of FhRWP expression could reduce the number of nucellar embryos, while its knockout resulted in abnormal axillary bud development. In overexpression experiments, FhRWP was identified as having the unique capability of inducing the embryogenic callus formation in MO stem segments, possibly through the regulation of the WUS‐CLV signaling network and the ABA and cytokinin pathway, marking the inaugural demonstration of FhRWP's potential to reignite somatic cells' embryogenic fate. This study reveals the pleiotropic function of RWP in citrus and constructs a regulatory network during adventitious embryo formation, providing a new tool for bioengineering applications in plant regeneration. Significance Statement: FhRWP plays a central role in regulating multiple developmental phenotypes, including axillary bud differentiation, nucellar embryo formation, and somatic embryogenesis in citrus. [ABSTRACT FROM AUTHOR]

SUMMARY: Plants possess an outstanding capacity to regenerate enabling them to repair damages caused by suboptimal environmental conditions, biotic attacks, or mechanical damages impacting the survival of these sessile organisms. Although the extent of regeneration varies greatly between localized cell damage and whole organ recovery, the process of regeneration can be subdivided into a similar sequence of interlinked regulatory processes. That is, competence to regenerate, cell fate reprogramming, and the repatterning of the tissue. Here, using root tip regeneration as a paradigm system to study plant regeneration, we provide a synthesis of the molecular responses that underlie both regeneration competence and the repatterning of the root stump. Regarding regeneration competence, we discuss the role of wound signaling, hormone responses and synthesis, and rapid changes in gene expression observed in the cells close to the cut. Then, we consider how this rapid response is followed by the tissue repatterning phase, where cells experience cell fate changes in a spatial and temporal order to recreate the lost stem cell niche and columella. Lastly, we argue that a multi‐scale modeling approach is fundamental to uncovering the mechanisms underlying root regeneration, as it allows to integrate knowledge of cell‐level gene expression, cell‐to‐cell transport of hormones and transcription factors, and tissue‐level growth dynamics to reveal how the bi‐directional feedbacks between these processes enable self‐organized repatterning of the root apex. [ABSTRACT FROM AUTHOR]

Somatic embryogenesis (SE) is a biotechnological tool used to generate new individuals and is the preferred method for rapid plant regeneration. However, the molecular basis underlying somatic cell regeneration through SE is not yet fully understood, particularly regarding interactions between the proteome and post-translational modifications. Here, we performed association analysis of high-throughput proteomics and phosphoproteomics in three representative samples (non-embryogenic calli, NEC; primary embryogenic calli, PEC; globular embryos, GE) during the initiation of plant regeneration in cotton, a pioneer crop for genetic biotechnology applications. Our results showed that protein accumulation is positively regulated by phosphorylation during SE, as revealed by correlation analyses. Of the 1418 proteins that were differentially accumulated in the proteome and the 1106 phosphoproteins that were differentially regulated in the phosphoproteome, 115 proteins with 229 phosphorylation sites overlapped (co-differential). Furthermore, seven dynamic trajectory patterns of differentially accumulated proteins (DAPs) and the correlated differentially regulated phosphoproteins (DRPPs) pairs with enrichment features were observed. During the initiation of plant regeneration, functional enrichment analysis revealed that the overlapping proteins (DAPs-DRPPs) were considerably enriched in cellular nitrogen metabolism, spliceosome formation, and reproductive structure development. Moreover, 198 DRPPs (387 phosphorylation sites) were specifically regulated at the phosphorylation level and showed four patterns of stage-enriched phosphorylation susceptibility. Furthermore, enrichment annotation analysis revealed that these phosphoproteins were significantly enriched in endosomal transport and nucleus organization processes. During embryogenic differentiation, we identified five DAPs-DRPPs with significantly enriched characteristic patterns. These proteins may play essential roles in transcriptional regulation and signaling events that initiate plant regeneration through protein accumulation and/or phosphorylation modification. This study enriched the understanding of key proteins and their correlated phosphorylation patterns during plant regeneration, and also provided a reference for improving plant regeneration efficiency. [ABSTRACT FROM AUTHOR]

Petiole segments of an economically ornamental plant Oxalis triangularis A.st.-Hil have been used in the present study for rapid, reliable and systematic in vitro propagation. The morphogenic effect of a-Naphthalene acetic acid (NAA) at various concentrations (0.5 - 3.0 mg/L) was studied individually or in combination with 6-benzylaminopurine (BAP). Superior multiplication rates were achieved on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BAP. Of the tested combinations, maximum shoot regeneration (100.00 %), mean shoot number (14.60 ± 0.37 shoots per segment), and shoot length (18.11 ± 0.30 mm) were recorded on MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BAP after 6 weeks of incubation. Half-strength MS medium augmented with 1.0 mg/L indole-3-butyric acid (IBA) was the optimal medium for in vitro root induction, (24.60 ± 0.37 roots per shoot with 9.10 ± 0.32 mm in length) after 6 weeks of incubation. The regenerated plantlets showed 100 % survival success during acclimatization and exhibited normal growth characteristics and morphology. This optimized protocol is cost-effective and highly efficient for the rapid mass propagation of Oxalis triangularis A.st.-Hil. [ABSTRACT FROM AUTHOR]

Aquatic plants are grown in aquaria for their beauty and to maintain the quality of water. The explants of Lobelia cardinalis L. were obtained from the Aquatic Plant Center Co., Ltd., Thailand. In vitro clonal propagation offers alternative strategy for its rapid clonal multiplication. In this study, multiple and rapid propagations of Lobelia cardinalis L. with tissue culture techniques were aimed. Highly efficient and repeatable in vitro regeneration protocol was established from nodal segments of Lobelia cardinalis L. Various concentrations and combinations of various plant growth regulators (PGRs) were employed to induce multiple shoots, shoot elongation, number of leaves and rooting of shoots to obtain complete plantlets of Lobelia cardinalis L. Among 2 PGRs such as 6-benzylaminopurine (BAP) and a-Naphthalene acetic acid (NAA) tested for multiple shoot induction. Regenerated shoots had a higher number of shoots on MS medium contained cytokinins with auxins. The maximum shoot proliferation (100 %), number of shoots per explant (6.20 ± 0.51 shoots), shoot length (11.67 ± 0.69 mm) and number of leaves per explant (58.10 ± 0.38 leaves per explant) were observed in MS medium supplemented with 1.0 mg/L BAP and 2.0 mg/L NAA. Rooting was achieved within 3 to 4 weeks on all the rooting media, but MS medium augmented with 1.0 mg/L indole-3-butyric acid (IBA) produced the maximum number of strong and healthy roots (11.70 ± 0.27 roots). The regenerated complete plantlets with healthy roots and shoot system were transferred to 3.5 cm diameter black net plastic pots containing rockwool medium and successfully acclimatized with a survival rate of 100 % in the greenhouse and no phenotypic variations were observed among regenerated plants. The success of this protocol offers highly efficient method of the plant multiplication, which would be beneficial for plant tissue culturist, and nursery people where regular supply of plants is a large number required. This protocol can be utilized for commercial scale propagation. [ABSTRACT FROM AUTHOR]

A group of new hydrogel materials combining high physical properties and pronounced antibacterial activity has been developed. These are composite hydrogels "cellulose-polyacrylamide" based on cellulose matrices of two types: bacterial or regenerated plant cellulose. To form biologically active materials, a method of introducing cerium oxide nanoparticles with sizes less than 5 nm was elaborated. The developed technology allows to obtain hydrogels with the content of cerium oxide (in swollen material) up to 0.4–0.5 wt%. Variations of the ratio of gel components concentrations, type of matrix cellulose and synthesis conditions allow to change the complex of mechanical properties of the material within a wide range, in particular, to obtain both soft, low-modular nanocomposites and hydrogels with record high rigidity. Significant differences in mechanical properties of hydrogels based on different types of cellulose fully correlate with the difference in morphological characteristics of these two groups of materials, revealed by SEM. No palpable effect of nanoparticles on the morphological characteristics of the material was revealed. Both cerium oxide nanoparticles and hydrogels containing cerium oxide showed antibacterial activity against S. aureus ATCC 29213, S. aureus ATCC 43300, P. aeruginosa ATCC 27853, K. pneumoniae ATCC 33495. Different intensity of growth depression of the bacterial cells was determined depending on the samples composition and of the bacteria species. [ABSTRACT FROM AUTHOR]

Malus 'Baiyun' (registration no. 20210210), a new crabapple cultivar, was registered in 2021 by the Nanjing Forestry Unversity. However, the difficult rooting has greatly limited the production of high-quality M. 'Baiyun' in industrialization development. There is thus a pressing need to develop an organogenesis protocol for the in vitro propagation of M. 'Baiyun' to alleviate a shortage of high-quality M. 'Baiyun' seedlings. The results showed that choosing the apical bud in mid-March was an excellent explant material. To promote proliferation, the highest proliferation (6.27) of apical shoots was cultured on Murashige and Skoog (MS) medium supplemented with 0.5 mg·L−1 6-benzylaminopurine(6-BA) + 0.05 mg·L−1 indole-3-butyric acid (IBA). Subsequently, a 100% rooting rate, average number of roots per shoot of 6.2 and maximum length of roots of 4.96 cm were obtained on half-strength Murashige and Skoog (1/2 MS) medium with the application of 0.5 mg·L−1 naphthaleneacetic acid (NAA) or 0.6 mg·L−1 NAA + 0.7 mg·L−1 IBA. Additionally, thick and lateral roots were obtained with 0.6 mg·L−1 NAA + 0.7 mg·L−1 IBA. Our study is the first to establish an effective organogenesis protocol for new crabapple cultivars using stem segments. [ABSTRACT FROM AUTHOR]

Sesuvium portulacastrum L. is a dicotyledonous halophyte belonging to the family Aizoaceae. Its young leaves are highly nutritious, and many ecotypes are used as leafy vegetable and medicinal crops. Additionally, due to their tolerance to soil salinity, flooding, and high temperatures, some ecotypes are used for the remediation of saline soils. As a result, there is an increasing need for a large number of disease-free S. portulacastrum propagules. This study developed an efficient protocol for the regeneration of S. portulacastrum through indirect shoot organogenesis. Leaf explants were cultured on Murashige and Skoog basal medium supplemented with different concentrations of zeatin (ZT) and indole-3-acetic acid (IAA). Callus was induced in all explants cultured with 1.5 mg/L ZT only or 1.5 mg/L ZT with 0.5 mg/L IAA. The callus was cut into small pieces and cultured on the same medium on which it was initially induced. ZT at 1.5 mg/L induced 73.7% of callus pieces to produce adventitious shoots, and the shoot numbers per callus piece were up to 20. To improve the in vitro rooting of adventitious shoots, commonly known as microshoots or microcuttings, an endophytic fungus, Cladosporium 'BF-F', was inoculated onto the rooting medium. 'BF-F' substantially enhanced rooting and plantlet growth, as the root numbers were three times more and plantlet heights were 70% greater than those without 'BF-F' inoculation. To detect the genes involved in the enhanced rooting and plantlet growth, qRT-PCR analysis was performed. Results showed that genes related to auxin responses and nitrogen uptake and metabolism were highly upregulated in 'BF-F'-inoculated plantlets. Plants inoculated with 'BF-F' grew vigorously after being transplanted into a sand–soil substrate. Thus, this study not only established an efficient protocol for the regeneration of S. portulacastrum but also developed a novel method for improving the rooting of microshoots and plantlet growth. The established propagation system could be used for producing a large number of S. portulacastrum plantlets for commercial use and also for genetic transformation. [ABSTRACT FROM AUTHOR]

Temporary immersion system (TIS) cultures are reported to be superior when compared to semi-solid (SS) and liquid (LQ) cultures for the in vitro plant regeneration of many plant species. In the present study, we used a TIS for plant regeneration of Gerbera jemesonii "Shy Pink" and compared the results with that of SS and LQ cultures. The number of shoots regenerated in the SS, LQ, and TIS cultures was 6.93, 3.13, and 3.03, respectively. The shoots regenerated with the SS and LQ cultures demonstrated 3.33 and 4.22% hyperhydricity, whereas the shoots regenerated with the TIS were healthy even though the number of shoots regenerated was less. The plantlets regenerated with the TIS demonstrated higher values for the number of roots, root length, biomass of the plantlets, leaf length/width, and area compared to the SS and LQ cultures. When the G. jemesonii "Shy Pink" plants were regenerated using the TIS, their levels of photosynthetic pigments were highest. The number of stomata on the abaxial surface of their leaves was 11.40, and the frequency of closed stomata was 59% for the plants regenerated with the TIS. The number of stomata was 21.4 and 14.5 for the plants regenerated with the SS and LQ cultures, respectively. Meanwhile, the frequency of closed stomata was 13% and 15% for the plants regenerated with SS and LQ cultures. Furthermore, G. jemesonii "Shy Pink" showed the highest survival of plants when regenerated in the TIS compared to SS and LQ cultures. The TIS was found to be the most suitable culture system for plant regeneration of G. jemesonii "Shy Pink" compared to SS and LQ cultures. [ABSTRACT FROM AUTHOR]

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Background: Hulless barley (Hordeum vulgare L. var. nudum Hook. f.) is a significant cereal crop and a substantial source of forage for livestock. Long non-coding RNAs (lncRNAs) and metabolites play crucial roles in the nutrient accumulation and regeneration of hulless barley plants following mowing. The study aimed to identify differentially expressed lncRNAs and metabolites in hulless barley plants by analyzing transcriptomic and metabolomic datasets at 2 h, 24 h, and 72 h following mowing. Results: The study revealed that 190, 90, and 438 lncRNA genes were differentially expressed at the 2 h, 24 h, and 72 h time points compared to the non-mowing control. We identified 14 lncRNA genes—11 downregulated and 3 upregulated—showing consistently significant differential expression across all time points after mowing. These differentially expressed lncRNAs target genes involved in critical processes such as cytokinin signaling, cell wall degradation, storage protein accumulation, and biomass increase. In addition, we identified ten differentially expressed metabolites targeting diverse metabolic pathways, including plant hormones, alkaloids, and flavonoids, before and after mowing at various time points. Endogenous hormone analysis revealed that cytokinin most likely played a crucial role in the regeneration of hulless barley after mowing. Conclusions: This study created a comprehensive dataset of lncRNAs, metabolites, and hormones in hulless barley after mowing, revealing valuable insights into the functional characteristics of lncRNAs, metabolites, and hormones in regulating plant regeneration. The results indicated that cytokinin plays a significant role in facilitating the regeneration process of hulless barley after mowing. This comprehensive dataset is an invaluable resource for better understanding the complex mechanisms that underlie plant regeneration, with significant implications for crop improvement. [ABSTRACT FROM AUTHOR]

Plant growth regulators (PGRs) play a vital role in the induction of morphogenesis in vitro. Synthetic PGRs are commonly used to induce organogenesis and somatic embryogenesis from various explants, while natural substances are rarely utilized. This study aimed to enhance the regenerative response in Nicotiana tabacum leaf explants using Tulsi (Ocimum sanctum) leaf extract and to elucidate the biochemical interactions during modulation of endogenous plant growth regulators, including indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin, and 6-(γ, γ-dimethylallylamino) purine (2iP). Tulsi leaf extract significantly improved shoot production through interactions between endogenous hormones and those present in the extract, which enhanced stress mitigation. The 20% Tulsi leaf extract treatment produced significantly more shoots than the control, coinciding with increased endogenous IAA and zeatin levels starting on day 10 in culture. Furthermore, ABA and zeatin concentrations increased on days 15 and 25, respectively, in the 20% Tulsi extract treatment, suggesting their role in the induction of somatic embryo-like structures. ABA likely acts as an activator of stress responses, encouraging the development of these structures. Additionally, 2iP was involved in the induction of both forms of regeneration in the 10% and 20% extract treatments, especially in combination with ABA. These results suggest that Tulsi leaf extract holds promising potential as a natural supplement for increasing plant regeneration in vitro and advancing our understanding of how natural extracts of plant origin can be harnessed to optimize plant regeneration processes in vitro. [ABSTRACT FROM AUTHOR]

Ungernia sewertzowii (US) and U. victoris (UV) are medicinal plants and sources of biologically active compounds for pharmaceutical needs. The leaves of US contain 0.29–0.81% sum of alkaloids with a predominance of lycorine, which is 0.04–0.46% in leaves and 0.15–0.38% in bulbs. Lycorine is used to treat acute and chronic bronchitis. The leaves of UV contain 0.27–0.71% sum of alkaloids with a predominance of galanthamine—0.13–1.15%. Galanthamine is used to treat mild-to-moderate dementia (Alzheimer's disease). The natural populations of US and UV are in danger as sources of income for local people. To resolve this problem, two protocols for microclonal propagation were developed to replace natural raw materials with in vitro regenerated plants. Callusogenesis of US and UV was induced on Murashige and Skoog (MS) nutrient media with 2.4D (0.5 mg/L) in combination with BAP (0.5 mg/L), Kin (0.5 mg/L), or Zea (0.5 mg/L). Direct (for US) and indirect (for US and UN) organogenesis were observed on MS with BAP (0.5 mg/L) or Kin (0.5 mg/L) in combination with IAA (0.5 mg/L) or NAA (0.5 mg/L). Direct organogenesis resulted in 3–5 bulbs of US on one explant; indirect organogenesis resulted in up to 100–150 bulbs of US and UV on one explant within 6 months, or five to six subcultures after transferring the callus to the nutrient medium. The tissue cultures of US and UV were characterized by very low data on antioxidant activity based on IC50 values for DPPH and ABTS radical scavenging activities, whereas in vitro regenerated plants (leaves and bulbs) had higher data. We concluded that in vitro regenerated plants are valuable sources of lycorine and galanthamine, which allow the protection of the natural populations of these two species from extinction. [ABSTRACT FROM AUTHOR]

Galanthamine is an immensely valuable alkaloid exhibiting anti-cancer and antiviral activity. The cultivation of plant tissues in in vitro conditions is a good source for the synthesis and enrichment of secondary metabolites of commercial interest. In this study, the Amaryllidaceae alkaloid galanthamine was quantified in three Zephyranthes species, such as Zephyranthes candida, Zephyranthes grandiflora, and Zephyranthes citrina, and the impact of the methyl jasmonate (MJ) signaling molecule on galanthamine accumulation was monitored in in vitro-derived plant tissues. This is the first ever study of the MJ-regulated accumulation of galanthamine in in vitro-grown Zephyranthes tissues. Shoot regeneration was obtained in all three Zephyranthes species on Murashige and Skoog (MS) medium containing 2.0 mgL−1 benzylaminopurine (BAP) + 0.5 mgL−1 naphthalene acetic acid (NAA). The regenerated shoots were rooted on a medium containing 2.0 mgL−1 indole butyric acid (IBA). A GC-MS study of Zephyranthes extracts revealed the presence of 34 phyto-compounds of varied levels with therapeutic activities against diseases. The galanthamine content was quantified in plant parts of the three Zephyranthes species using high-performance thin layer chromatography (HPTLC); the maximum was found in Z. candida bulb (2.41 µg g−1 dry wt.), followed by Z. grandiflora (2.13 µg g−1 dry wt.), and then Z. citrina (2.02 µg g−1 dry wt.). The galanthamine content showed bulb > leaf > root source order. The in vitro-generated plantlets were treated with different MJ concentrations, and the galanthamine yield was measured in bulb, leaf, and root tissues. The highest galanthamine content was recorded in bulbs of Z. candida (3.97 µg g−1 dry wt.) treated with 150 µM MJ, showing an increase of 64.73% compared to the control. This accumulation may be attributed to MJ-induced stress, highlighting the potential commercial synthesis of galanthamine in vitro. [ABSTRACT FROM AUTHOR]

Genetic variability induced by cell and tissue culture techniques provides a new source of diversity for improvement of ornamental plants species. For this purpose, the effect of Thidiazuron (TDZ) on callus induction and number of subcultures of Salvia splendens was studied. The results showed that the MS medium supplemented with TDZ (0.5 mg/l) and Indole Acetic Acid IAA (0.1 mg/l) produced the highest percentage for explants producing callus (60%). For shoot multiplication, the best results were achieved when shoot tips were cultured on MS medium supplemented with TDZ (0.2 mg/l) alone. For subculture the same concentration of TDZ (0.2 mg/l) in media of eleven subcultures were performed at 21-day intervals over a total period of 231 days. For molecular variation detection, SCoT molecular markers were employed. Five SCoT primers were used and a total of 24 bands were obtained. The results showed high level of polymorphism between parent and their regenerated plants (subculture No. 11). These markers revealed distinctly different patterns of DNA fragments in all somaclones, and some distinctive bands were linked to the regenerated plants. For rooting, the best rooting percentage (100.00%), highest number of roots/shoot (7.00) and root length (2.58 cm) were observed when the shoots were cultured on MS hormonefree medium supplemented with 15 g sucrose/l. Plantlets were successfully acclimatized on Peat moss + perlite (1:1) with a survival rate of 100 %. [ABSTRACT FROM AUTHOR]

SUMMARY: The main bottleneck in the application of biotechnological breeding methods to woody species is due to the in vitro regeneration recalcitrance shown by several genotypes. On the other side, woody species, especially grapevine (Vitis vinifera L.), use most of the pesticides and other expensive inputs in agriculture, making the development of efficient approaches of genetic improvement absolutely urgent. Genome editing is an extremely promising technique particularly for wine grape genotypes, as it allows to modify the desired gene in a single step, preserving all the quality traits selected and appreciated in elite varieties. A genome editing and regeneration protocol for the production of transgene‐free grapevine plants, exploiting the lipofectamine‐mediated direct delivery of CRISPR–Cas9 ribonucleoproteins (RNPs) to target the phytoene desaturase gene, is reported. We focused on Nebbiolo (V. vinifera), an extremely in vitro recalcitrant wine genotype used to produce outstanding wines, such as Barolo and Barbaresco. The use of the PEG‐mediated editing method available in literature and employed for highly embryogenic grapevine genotypes did not allow the proper embryo development in the recalcitrant Nebbiolo. Lipofectamines, on the contrary, did not have a negative impact on protoplast viability and plant regeneration, leading to the obtainment of fully developed edited plants after about 5 months from the transfection. Our work represents one of the first examples of lipofectamine use for delivering editing reagents in plant protoplasts. The important result achieved for the wine grape genotype breeding could be extended to other important wine grape varieties and recalcitrant woody species. [ABSTRACT FROM AUTHOR]

medium supplemented with exogenous putrescine(Put), spermidine(Spd), and spermine(Spm). The results were as follows:(1)Exogenous Put, Spd and Spm treatments significantly increased the EC proliferation rate and reduced the amount of induced somatic embryos and number of germinations. The proliferated EC cells after exogenous PA treatments were more consistent in size and stained deeply and evenly. Furthermore, multicellular proembryos in EC were reduced, and fully differentiated early cotyledon embryos could be seen. (2)All the exogenous PA treatments significantly increased the endogenous PA content in EC. Among them, Put treatment had the highest content of each endogenous PA component and total PA. When the EC proliferated on the medium containing exogenous PAs was transferred to the medium without exogenous PAs(recovery culture)for proliferating, the Put content in the EC was still significantly higher than the control, however, the endogenous Spd and Spm were significantly decreased. (3)Exogenous Put treatment significantly increased the activities of ornithine decarboxylase(ODC), arginine decarboxylase(ADC), and diamine oxidase(DAO)in EC, while exogenous Spd and Spm treatments significantly reduced the activities of ODC and ADC in EC, and exogenous Spd significantly increased the polyamine oxidase(PAO)activity. When transferred to the recovery culture medium, the ADC and DAO activities of newly proliferated EC were significantly lower than those of EC cultured with exogenous PAs, but there was no significant difference in ODC and PAO activities. In summary, the exogenous PAs can affect endogenous PAs content by regulating the activities of enzymes related to PAs metabolism, thereby affecting EC proliferation and somatic embryo induction in litchi. These results provide a basis for further study on the mechanism of PAs regulating embryogenesis, and improve litchi regeneration efficiency in vitro. [ABSTRACT FROM AUTHOR]

In response to the decline of Central European spruce monocultures driven by various factors, the Demonstration Object of Reconstruction of Spruce Forests (DORS) was established in Husárik locality, Javorníky Mts., northwestern Slovakia. The area includes the Husárik trial site, where the applicability and efficiency of different artificial regeneration methods are studied. The trial was established on a 24-ha area cleared following the outbreak of spruce bark beetles in 2011. Its altitude is 800 m a.s.l., aspect NW, slope 30%, the soil is Ranker on the soft flysch sandstone bedrock. Our study covered 4 conifers - Norway spruce (spruce), European larch (larch), silver fir (fir), and Douglas fir (doug fir). Each species was regenerated using 4 different approaches: planting of commercial bareroot transplants (BR), planting of container transplants (CON), direct seeding (DS) and vegetative cell seeding using seed shelters (VCS). Results concerning the nine-year development of transplants and seedlings, along with the calculation of cost-efficiency, are presented. As to the species, BR and CON transplants of spruce and larch reached the best survival and height. The DS larch was the most cost-efficient method of establishment of a successfully established plantation (survival > 50%; stem height > 2/3 of the weed height; ratio of damaged individuals < 50%) with a total cost of 2 372 EUR·ha-1. On the contrary, the slow initial growth of fir and Douglas fir and their extensive damage resulted in the incomparably higher cost of establishment of their successfully established plantation, such as 4 980 EUR·ha-1 for five-years-old BR fir transplants. Our findings documented that current efforts related to the restoration of salvage-felled clearings remained difficult, especially in the case of introduction or reestablishment of coniferous tree species more vulnerable to open site conditions. [ABSTRACT FROM AUTHOR]

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Plant invasions have a negative impact on biodiversity and lead to species loss. Although studies on traits promoting invasiveness have been largely developed, comparative studies on germination traits of closely related native versus alien invasive species, which also take into account threatened species, are lacking. We analysed the germination requirements of two congeneric Lindernia species inhabiting paddy field in Northern Italy. Germination tests were conducted exposing seeds of both species across a broad range of temperature and conditions (i.e., cold-wet stratification, dark condition, alternate temperature, gibberellic acid). The invasive L. dubia showed higher and faster germination, occurring over a broader range of temperatures compared to the native threatened L. procumbens, along with a lighter non-deep physiological dormancy. These results show a competitive advantage of the alien species already in the early stages of plant regeneration and provide a comprehensive overview of the germination requirements, necessary for the development of future conservation and management plans. [ABSTRACT FROM AUTHOR]

The objective of this research was to analyze the P. brutia natural regeneration and the environments where it was established in the absence of a wildfire in the open formations of the species in the middle elevations of the central part of Cyprus. Forty-eight rectangular plots of 0.1 ha were established in three site productivity types. Individuals of the species with a height from 0.1 m to 1.5 m were considered regeneration plants. Within each plot, various measurements and estimations were made. Moreover, 480 hemispherical photographs were taken. Additionally, hemispherical photographs were taken above each of the recorded naturally regenerated P. brutia plants. In all the site productivity types, the most regeneration plants were established and grew under the process of facilitation. In each of the site productivity types, there were no differences in the light condition diversity between the environments where the regeneration plants grew and the existing light conditions. Regeneration exhibited a small number of plants and constituted only a very small proportion of all trees in the three site productivity types. To achieve sustainability in P. brutia forests, forest practices must develop strategies for the enhancement of P. brutia regeneration in the studied area and in analogous environments. [ABSTRACT FROM AUTHOR]

Doubled haploid technology is, so far, the fastest route to induce a true homozygous state in plants. True homozygous plants are particularly important for breeders, as they can facilitate hybrid breeding and are useful in fixing traits in a breeding line. Fabaceae species are of great importance in food and feed production; however, they are far behind other families with respect to the development of effective haploidization protocols. Here, we present the most recent status of research on haploidization protocols in cool-season grain legume crops, including dry peas, chickpeas, faba beans, lentils, lupines, and grass peas. The first four species are primarily for human consumption; the latter are utilized as forage. All the mentioned species have been subject to haploidization trials; however, repeatable protocols, including the regeneration of confirmed haploid or doubled haploid plants, have not been elaborated. Research in field pea, chickpea, grass pea, and lupine is promising, with the reported regeneration of microspore-derived embryos in all four species. Repeatable plant regeneration has been reported only in field peas and chickpeas. The most recent achievements on haploidization through male and female gametophytes in faba bean are also presented. The key factors for the effective stimulation of haploid cell development in cool-season legumes are reviewed, providing a useful basis for future efforts toward haploidization in this group. [ABSTRACT FROM AUTHOR]

Gaillardia pulchella Foug. is a widely studied plant because of its high pharmacological and ornamental value. The leaves of G. pulchella were used for inducing callus and subsequent plant regeneration as it is the primary source of phytocompounds. The purpose of the present investigation was to formulate an in vitro propagation method for Gaillardia by using leaf explants in MS (Murashige and Skoog) medium. The best callus induction was observed on high (2.0 mg/L) α-naphthalene acetic acid (NAA) and a low (0.5 mg/L) 6-benzylaminopurine (BAP) with callus induction frequency of 91.66%. The leaf callus also demonstrated high caulogenesis ability (95.83%), with an average 5.2 shoots/callus mass at 0.5 mg/L BAP and 2.0 mg/L NAA. Indole Acetic acid (IAA) at 1.0 mg/L had the maximum rooting percentage (79.17%) with 12.4 roots per shoot. Rooted plantlets were later transferred to greenhouse conditions, showing a survivability rate of 75–80%. The physiological parameters, i.e., phenolic compounds and the flavonoids' level, in the DPPH assay were higher in leaves obtained in vitro compared to callus formed from leaves and field-obtained (mother) leaves. Gas chromatography–mass spectrometry (GC–MS) analysis of methanol extracts of leaves (in vivo and in vitro) and leaf callus presented a wide array of compounds. In callus extract, some 34 phytocompounds were identified. Some of them were 3-hydroxy-2,3-dihydromaltol (25.39%), isoamyl acetate (11.63%), palmitic acid (11.55%), 4-methyloxazole (7.54%), and 5-methoxypyrrolidin-2-one (7.49%). Leaves derived in vivo and in vitro had 45 and 28 phytocompounds, respectively, belonging to different classes like lignans, phenols, terpenoids, alkaloids and fatty acids, etc. Those findings demonstrated that the leaf derived callus and the leaves are the potential stable source of several compounds with medicinal importance. The developed protocol may provide an alternative source of compounds without affecting wild flora. [ABSTRACT FROM AUTHOR]

The dispersal of large-seeded species strongly depends on medium-sized and large frugivores, such as primates, which are highly susceptible to population declines. In the Atlantic Forest, brown howler monkeys Alouatta guariba are medium-sized folivorous-frugivorous species that are likely to occur in small to large fragments where the largest frugivores are extinct. However, populations of this primate have been suffering from forest fragmentation, habitat loss, hunting, and the direct and indirect effects of yellow fever outbreaks, which increase the importance of understanding their role as seed dispersers and the impacts of their potential loss. The richness and abundance of large-seeded species might also be reduced in smaller fragments, which could directly affect the magnitude of the potential impact of disperser extinction on plant recruitment. Here, we tested the following mutually exclusive predictions on the effect of fragment size on plant richness and relative density of medium- and large-seeded species consumed by brown howler monkeys in fragments smaller than 1500 ha: the number and the relative density of plant species potentially affected by the local extinction of these monkeys will be (1) directly related to forest fragment size, or (2) not related to forest fragment size. Plant richness and the relative density of large- and medium-sized seed species consumed by brown howler monkeys did not vary with fragment size, corroborating our second prediction. Thus, the local extinction of brown howler monkeys would have a similar potentially negative impact on plant regeneration for the range of tested fragment sizes. We discuss the limitations of our results and suggest other lines of enquiry for the refinement of our conclusions. [ABSTRACT FROM AUTHOR]