Search Results (268)

Drought-induced water stress is a major constraint on crop productivity, especially under climate change conditions. In previous work, we isolated a fungal endophyte, Leptobacillium sp. Sl27, from Solanum lycopersicum and found that its growth-promoting effects were dependent on the tomato genotype. In this study, we investigated whether Sl27 modulates early plant responses to water stress in the following two tomato genotypes with differing sensitivities to drought: ADX2 and MO-10. Seeds were inoculated with the endophyte, and 4-week-old seedlings were subjected to water stress by withholding watering for 12 days under controlled growth chamber conditions. We assessed plant performance by measuring physiological parameters (including photosynthetic rate, transpiration, and stomatal aperture) and overall stress response by leaf phenotypic traits. Under severe stress conditions, Sl27-inoculated plants, particularly in the more sensitive genotype MO-10, showed reduced early damage and partially maintained physiological activity during initial stages of stress. However, under prolonged stress, all plants reached similarly high levels of damage, indicating that the effect was transient and did not confer sustained drought tolerance. To explore plant performance under more moderate and agronomically relevant conditions, a second independent experiment was conducted in MO-10 using a controlled water deficit (40% field capacity) and plantlet-stage inoculation. In this experimental context, Sl27 primarily promoted plant growth, increasing shoot and root biomass, with a non-significant trend toward improved performance under stress. Overall, these results indicate that Sl27 does not confer classical drought tolerance but instead improves plant performance and modulates early responses to water deficit in a genotype-dependent manner, with stronger effects observed in the more sensitive genotype MO-10. Full article

Efficient micropropagation systems are essential for the large-scale production of uniform and high-quality plant material in aromatic species. In this study, the effects of gibberellic acid (GA₃; 1.4, 2.8, and 5.6 $\mathsf{\mu }$M) and methyl jasmonate (MeJA; 2.2, 4.4, and 8.8 $\mathsf{\mu }$M) were evaluated on the in vitro performance of Artemisia pontica across two successive subcultures. Morphological, physiological, and biochemical parameters were assessed, and the most effective treatment was further investigated through scanning electron microscopy (SEM) to evaluate leaf trichome characteristics. GA₃ treatments significantly enhanced shoot growth, shoot number, and relative growth rate, with the strongest response observed at 2.8 $\mathsf{\mu }$M. This concentration also promoted higher chlorophyll content and antioxidant activity, indicating improved physiological status and metabolic performance of plantlets. In contrast, MeJA treatments, particularly at 8.8 $\mathsf{\mu }$M, reduced growth performance and pigment accumulation, suggesting a less favorable physiological status for micropropagation. Multivariate analysis (PCA and hierarchical clustering) revealed a clear separation among treatments, with GA₃ at 2.8 $\mathsf{\mu }$M associated with a coordinated increase in growth-related and antioxidant traits. SEM analysis showed that GA₃ influenced leaf epidermal structure, increasing the density of T-shaped, non-glandular trichomes and the diameter of glandular secreting trichomes, suggesting structural adjustments linked to metabolic activity. Overall, the results indicate that GA₃ at 2.8 $\mathsf{\mu }$M represents the most effective supplementation under the tested conditions, promoting a balanced improvement in shoot proliferation, physiological performance, antioxidant activity, and selected structural traits. Full article

This review summarizes recent studies on the use of nanoparticles (NPs) in plant in vitro clonal micropropagation and secondary metabolite production. The analyzed applications include culture initiation, shoot multiplication, rooting, acclimatization, callus culture, and hairy root culture. Because NPs’ effects are strongly endpoint-dependent, their effectiveness is evaluated separately for micropropagation endpoints, including contamination control, explant survival, multiplication rate, shoot and root development, and plantlet quality, and for metabolite-production endpoints, including biomass accumulation, target metabolite concentration, and total metabolite yield. Based on the quantitative analysis of published data, the most frequently beneficial NP size range was 20–60 nm, whereas effective concentrations, combining a positive effect on plant growth and the synthesis of secondary metabolites, were mainly within 1–120 mg L⁻¹. For the most extensively studied NPs, the corresponding indicative concentration ranges were 15–45 mg L⁻¹ for 25–40 nm Ag-NPs, 75–200 mg L⁻¹ for 15–45 nm ZnO-NPs, 120–150 mg L⁻¹ for 50–80 nm Se-NPs, and 90–145 mg L⁻¹ for 54–55 nm Si-based NPs. Ag- and carbon-based nanomaterials showed relatively strong overall responses in micropropagation datasets, whereas Ag- and Se-NPs were often associated with enhanced target metabolite accumulation. NP responses depend on particle composition, synthesis method, surface properties, dose, culture system, species, genotype, and may involve phytotoxic or residue-related risks. Full article

Micropropagation of Selenicereus hybrids is a key tool for breeding and conservation; however, further refining the balance between high multiplication rates and morphological quality remains a complex challenge within conventional protocols. This study explores targeted signaling modulation using nine bioactive small molecules—including three mammalian glycogen synthase kinase 3 (GSK3) inhibitors (TDZD-9, VP3.15 and VP0.7), three leucine rich repeat kinase 2 (LRRK2) inhibitors (JZ1.24, JZ1.3 and IGS4.75), and three phosphodiesterase (PDE) inhibitors—to complement traditional micropropagation. Explants were evaluated in two distinct contexts: a hormone-free basal medium (BM) and a plant growth regulator-supplemented medium (PIT2) and the response rates, yield, and quality were measured and integrated using a Global Efficiency Index (GEI). Results demonstrate that inhibitor efficacy is strictly context-dependent; while most molecules repressed budding in BM, they acted as response modulators by determining the specific type of morphogenic pathway in PIT2. Notably, the GSK3 inhibitor TDZD-9 reached the highest GEI (0.85) by maximizing productivity, whereas LRRK2 inhibitors effectively preserved architectural integrity. Flow cytometry confirmed cytogenetic stability across all treatments, with a 98.5% plantlet survival rate during acclimatization. In conclusion, the strategic integration of targeted signaling modulators and multi-parametric indices offers a refined and objective framework to enhance the efficiency of mass propagation protocols in pitahaya and other recalcitrant species. Furthermore, our findings provide new evidence of the strong potential of these small molecules as novel tools to improve plant micropropagation beyond traditional plant growth regulators. Full article

Efficient propagation of Hydrangea arborescens is essential for the stable production of high-quality plantlets. However, propagation via stem cuttings is often limited by environmental conditions and inconsistent rooting. This study aimed to identify an effective in vitro culture medium by integrating quantitative growth traits with image-based quality analysis. Seven culture media (M1–M7), consisting of Murashige and Skoog (MS), McCown Woody Plant (McCown), and Gamborg B5 basal media supplemented with different plant growth regulator combinations, were evaluated based on shoot number, root number, plant height, and fresh weights, and plantlet quality was assessed using Green area, ExG (excess green index), and a composite z-score. Significant differences were observed among treatments. M5 and M7 produced the highest shoot numbers, and M7 showed the greatest fresh weight. Image-based analysis indicated that M2 and M7 exhibited the highest overall quality, whereas M3 showed the lowest performance. Basal media types did not significantly affect plantlet quality, whereas hormone treatments enhanced both shoot multiplication and callus formation. A positive association was observed between callus formation rate and shoot number (Spearman’s ρ = 0.74, p < 0.001). Overall, M7 (Gamborg B5 medium supplemented with 30 g∙L⁻¹ sucrose, 1.5 mg∙L⁻¹ BA, and 0.25 g∙L⁻¹ gelrite) provided a balanced combination of high propagation efficiency and plantlet quality, and these findings contribute to the efficient production of high-quality planting materials. Full article

Globba bicolor Gagnep., an ornamental ginger of cultural importance in Thailand’s “Tak Bat Dok Mai” festival, faces conservation challenges due to climate change and slow natural propagation. Limited understanding of its cultivation and chemical composition further constrains sustainable utilization. This study provides the first integrated investigation of micropropagation using rhizome-derived explants under various combinations of exogenous hormones, acclimatization strategies, and comparative phytochemical profiling between wild and in vitro-propagated plants. An optimized clonal regeneration system was established from plantlets, with Murashige and Skoog (MS) medium containing 2.0 mg/L 6-benzylaminopurine (BA) and 0.5 mg/L 1-naphthaleneacetic acid (NAA), yielding the highest multiplication (9.10 shoots/explant and 12.40 roots/explant) after eight weeks of cultivation. During acclimatization, sand substrate proved superior, facilitating a 90% survival rate and enhanced physiological vigor. Comparative analysis revealed that while wild plants possessed significantly higher total phenolic (TPC) and total flavonoid (TFC) contents and antioxidant activities (DPPH, ABTS, and FRAP) than their in vitro counterparts, both sources maintained a rich diversity of chemical constituents. HPLC analysis identified cinnamic acid, rutin, and quercetin as major metabolites, while GC–MS detected 90 volatile compounds, with β-caryophyllene and β-pinene as predominant constituents. Notably, rhizomes of wild plants exhibited particularly high-value detections. To provide a rapid and non-destructive approach for linking chemical composition with antioxidant activity, FTIR-based chemometric models were applied, demonstrating high predictive accuracy (R²–cv = 0.9712–0.9862). These results provide a scientific foundation for the conservation and sustainable commercial utilization of G. bicolor as a potential source of bioactive natural products. Full article

Lilium, a traditional plant with dual medicinal and ornamental values, is restricted in its industrial development by the low natural propagation rate of bulbs and dependence on imported high-quality germplasm. To address this bottleneck, this study used new lines of LA hybrid lilies and Asiatic hybrid lilies (three cultivars) as experimental materials to establish an efficient and stable tissue culture and rapid propagation system. Key procedures including disinfection of different explants (bulb scales and capsules), adventitious bud induction and proliferation, rooting culture, as well as acclimatization and transplantation were systematically evaluated. The results showed that bulb scales were superior to capsule seeds as explants in tissue culture (contamination rate 9.44%, regeneration rate 11.92%). After disinfection with 75% ethanol combined with 10% sodium hypochlorite, the contamination rate could be controlled at 14.29–21.43%, and the regeneration rate reached 100%. Supplementation with 50 g·L⁻¹ sucrose + 1 mg·L⁻¹ 6-BA + 0.1 mg·L⁻¹ NAA (Treatment TA1), 50 g·L⁻¹ sucrose + 2 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ NAA (Treatment TA4) in MS medium, combined with dark culture, could effectively promote adventitious bud induction, proliferation and bulblet enlargement. For the rooting stage, the optimal media were 1/2 MS + 0.5 g·L⁻¹ activated charcoal + 2 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ NAA (Treatment TB4) or MS + 0.3 g·L⁻¹ activated charcoal + 2 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ NAA (Treatment TB1), and the highest rooting rate of ‘Pink Renault’ reached 100%. When plantlets from all three cultivars were combined and acclimatized and transplanted into sterilized peat soil, the overall survival rate was 89.33%. The TOPSIS method was also adopted for comprehensive evaluation to screen out the optimal culture conditions for different varieties. Based on phenotypic observation and physiological index data, ‘Pink Renault’ showed great potential as an excellent propagation germplasm. The integrated and optimized technical system provides a feasible solution for large-scale and industrialized seedling production of medicinal and ornamental lilies, and is of great practical significance for the efficient utilization of germplasm resources and sustainable development of the lily industry. Full article

Some actinobacterial species have been reported to improve plant growth due to their roles as biostimulants and biological control agents. In this study, the effect of actinobacterial isolate 27, obtained from the rhizospheric soil of melon plants and identified as Streptomyces calvus, was evaluated on the growth of Arabidopsis thaliana and tomato plants. In Arabidopsis, in vitro assays showed that after seven days of interaction, isolate 27 increased fresh weight by 1.4-, 1.5-, and 2.3-fold and lateral root number by 1.7-, 1.3-, and 2.5-fold under physical contact and split-plate systems (MS and ISP2 media), respectively, compared with non-inoculated plants. An increased β-glucuronidase (GUS, encoded by the uidA gene) signal was observed in primary and lateral roots of the Arabidopsis DR5::uidA reporter line during both interaction types, suggesting the activation of auxin-responsive pathways. In addition, isolate 27 rescued the rhd6 (root hair defective 6) mutant phenotype, restoring root hair formation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that isolate 27 emitted volatile organic compounds (VOCs), including an alcohol and several sesquiterpenes, and that this profile changed during interaction with Arabidopsis plantlets. In soil-based pot assays, inoculation with isolate 27 significantly enhanced the development of Arabidopsis plants after 23 days, both when applied alone and in co-inoculation with Trichoderma atroviride. Furthermore, isolate 27 stimulated tomato plant growth, leading to significant increases in fresh and dry biomass, as well as shoot and root lengths after 28 days. Overall, these results demonstrate that S. calvus isolate 27 promotes plant growth and development through the production of bioactive compounds that modulate plant growth pathways, including hormonal responses, highlighting its potential as a bioinoculant for sustainable and productive agricultural systems. Full article

Harsh environments and climate change hamper industrial hemp productivity. Under stress conditions, uniform germination and vigorous seedlings are key to sustaining crop establishment and performance. Trichoderma spp. are beneficial micromycetes, able to colonize plant roots and promote plant development even under abiotic stress conditions. Thus, the seed treatment with specifically selected Trichoderma isolates could be a useful strategy to enhance hemp seed germination and plantlet growth. In this view, a preliminary screening was performed with ‘Eletta campana’ cv. Nine out of 20 Trichoderma isolates enhanced the radicle growth (+66–111%); most of them resulted in good root colonization, but only four isolates significantly enhanced the shoot DW (+18–22%). Three isolates were selected for a pot experiment, compared to T. afroharzianum T22, to evaluate the effect on plant growth, root architecture, accumulation of photosynthetic pigments and stress-related compounds, and variation in antioxidant activity in 20-day-old plantlets. T. afroharzianum OR4 significantly promoted plantlet growth (+9% shoot DW and +11% leaf DW). The seed treatment had a low impact on the other variables studied, except in the case of foliar proline content, a marker of stress tolerance, that was greatly increased with T. afroharzianum T22 and T. atrobrunneum X44 (+32% and +17% DW). Full article

The rare and threatened pleurocarpous semi-aquatic moss Drepanocladus sendtneri (Amblystegiaceae) was the focus of an integrative conservation approach aimed at improving knowledge of its biological and ecological characteristics and enhancing its survival prospects. The results provide insights into both the axenic and xenic propagation of this species, as well as its biomass production under ex situ conditions. The KNOP medium proved to be the most suitable for propagation, particularly when demeristemized shoot tips were cultured in an upright orientation. Exogenous application of IBA increased the production of new shoots and reduced the time required to obtain substantial biomass under axenic conditions. Following successful acclimatisation to controlled xenic laboratory conditions, the moss was able to fully develop and spread in experimental basins maintained under outdoor botanical garden conditions, with humidity carefully regulated during dry periods. Within one year, a small number of initial plantlets expanded to cover approximately 4 dm², spreading efficiently over rainwater-soaked filter paper covered with an inert plastic mesh. These results provide practical guidance for the production and ex situ maintenance of D. sendtneri, thereby supporting the development and improvement of conservation action plans for this rare and threatened moss species. Full article

A simple method for the efficient high-throughput transformation of hybrid poplar (Populus tremula x alba clone 717 1B) is described. Factors considered in developing the method included the ease and efficiency of preparing large numbers of explants for transformation, and selection of culture media that enhanced cell and tissue growth while promoting shoot regeneration competence. We found that petiole explants from in vitro-cultured plantlets can be easily collected and prepared for transformation and regenerate shoots comparable to stem or leaf explants. Culturing petiole explants on Driver Kuniyuki Walnut (DKW) medium resulted in significantly greater tissue growth compared to Murashige Skoog (MS) medium. Moreover, the inclusion of low concentrations of thidiazuron (TDZ) in callus-inducing media (CIM) significantly enhanced shoot regeneration competence of cultured petiole explants. As a consequence, the combination of petiole explants cultured on DKW medium along with 2.2 ug/L TDZ during the callus induction phase resulted in rapid and efficient transformation of this hybrid poplar genotype. When applied to genomic approaches such as activation tagging or CRISPR-Cas9 and Cas12a gene editing, we obtained transformation efficiencies ranging between 70% and 90%. The described protocol provides a simple and efficient method that is easily scalable for high-throughput approaches, which could facilitate genome-wide methods for the rapid and efficient production of transformed hybrid poplars. Full article

Astragalus glycyphyllos (Fabaceae) is known to be a source of flavones, flavonols, and isoflavones, and its in vitro culture may promote the efficiency and sustainability of obtaining pharmacologically valuable fractions. The aim of this study was to develop an effective plantlet regeneration protocol for A. glycyphyllos, providing the accumulation of phenolic compounds and antioxidants in cultured tissues. The results show a maximum seed germination rate (67.8%) after scarification (mechanical with sandpaper followed by treatment with 50% sulfuric acid) and subsequent sterilization with 1.1% sodium hypochlorite solution. The maximum regeneration rate (95%) was achieved on Murashige and Skoog medium supplemented with 0.5 mg·L⁻¹ thidiazuron. A thidiazuron concentration of 0.05 mg·L⁻¹, combined with a twofold increase in iron chelate content, induced the maximum yield of total flavonoids (8.74 mg·g⁻¹ DW), and significant levels of total phenolics (4.15 mg·g⁻¹) and antioxidants (1.83 mg AAE·g⁻¹) in the microshoot tissues. HPLC analysis showed kaempferol glycosides (1.51 mg·g⁻¹) and acylated kaempferol glycosides (2.76 mg·g⁻¹) as major components. Formononetin in a modest amount (0.09 mg·g⁻¹) was detected in hydrolyzed extracts. The phenolic profiles of the microshoots and native plants coincided in hydroxycinnamic acid composition; meanwhile, quercetin glycosides were present only in in situ plants, and formononetin was found only in the plantlets. The results confirm the prospects of biotechnological methods for the industrial production of standardized medicinal raw materials. Full article

Ulluco (Ullucus tuberosus Caldas) is an Andean tuber crop of high nutritional and genetic importance. However, its vegetative propagation promotes the accumulation of pathogens and limits the availability of uniform, high-quality planting material. In this study, an efficient and reproducible in vitro micropropagation protocol was established for an ulluco genotype from the Amazonas region of Peru. Nodal segments were cultured on MS (Murashige and Skoog) medium supplemented with 6-benzylaminopurine (BAP) or kinetin (KIN) at increasing concentrations (0.0–2.0 mg L⁻¹). For rooting, in vitro-derived shoots were transferred to MS medium supplemented with indole-3-butyric acid (IBA) or 1-naphthaleneacetic acid (NAA) at the same concentration range (0.0–2.0 mg L⁻¹). The explants exhibited a high basal morphogenetic capacity; however, the addition of cytokinins significantly enhanced the response. KIN at 2.0 mg L⁻¹ achieved 100% regeneration, whereas BAP at 0.2 mg L⁻¹ maximized shoot proliferation, producing 2.07 shoots per explant. Shoot elongation was greater with KIN at 1.0 mg L⁻¹, reaching 39.15 mm. In the rooting phase, the response varied depending on the type and concentration of auxin. NAA at 0.1 mg L⁻¹ resulted in 100% rooting and produced the greatest root length (41.93 mm), whereas IBA at 0.1 mg L⁻¹ maximized the number of roots (4.67), although roots were shorter. Rooted plantlets exhibited 100% survival after eight weeks of acclimatization. This protocol provides an effective system for the rapid production of vigorous and uniform clonal plants and represents a useful tool for the propagation, conservation, and future biotechnological improvement of ulluco. Full article

Papaya (Carica papaya L.) is a highly cross-pollinated crop that exhibits considerable genetic variability when propagated through seeds, resulting in non-true-to-type progeny. Therefore, the development of an efficient in vitro regeneration system is essential for large-scale clonal propagation of elite cultivars. In the present study, a highly efficient and reproducible somatic embryogenesis protocol was developed for C. papaya var. TNAU Papaya CO 8 using immature zygotic embryos as explants. This study provides the first comprehensive comparative evaluation of three basal media, viz., Murashige and Skoog Medium, N6 Medium, and Woody Plant Medium, for somatic embryogenesis and plant regeneration in this variety, along with the optimization of polyamine-enriched media for enhanced plantlet recovery. The embryogenic potential of explants was assessed across different stages, including callus induction, somatic embryo development, plant regeneration, shoot elongation, rooting, and acclimatization. Maximum callus induction (81.96%) was observed on half-strength MS medium supplemented with 2,4-Dichlorophenoxyacetic acid under dark conditions, followed by ½ N6 (63.00%) and ½ WPM (58.02%). Somatic embryo initiation was highest on ½ MS medium containing 2.0 mgL⁻¹ 2,4-D (77.82%). Somatic embryos developed through distinct globular, heart, torpedo, and cotyledonary stages. Embryo maturation was significantly enhanced on MS medium supplemented with abscisic acid, polyethylene glycol, benzylaminopurine, and proline. The highest plantlet regeneration (85.02%) was achieved on MS medium enriched with putrescine, whereas comparatively lower regeneration was recorded on N6 (75.99%) and WPM (57.97%). Shoot elongation was significantly improved by supplementation with gibberellic acid (1.0 mgL⁻¹). Root induction was optimal on half-strength MS medium containing Indole-3-butyric acid, 1-Naphthaleneacetic acid, phloroglucinol, and activated charcoal, resulting in well-developed roots. Regenerated plantlets were successfully acclimatized in a cocopeat–vermicompost substrate with a survival rate of 74.01%. The optimized protocol provides a reliable and efficient system for large-scale clonal propagation and offers promising applications in genetic transformation and commercial production of papaya var. TNAU papaya CO 8. Full article

Bacterial pathogens secrete effector proteins that suppress plant immune responses and facilitate infection. This study focuses on Pectobacterium brasiliense NJAU180, a bacterial pathogen causing severe blackleg disease in potato plants in Inner Mongolia, China. Using exoproteomic analysis, plant-induced extracellular proteins were identified by comparing culture supernatants from P. brasiliense NJAU180 grown in minimal medium (MM) alone and in the presence of aseptically grown potato plantlets at an early growth stage (OD₆₀₀ ≈ 0.5). The results reveal PurK as a novel plant-induced extracellular protein, and deletion of purK markedly reduces virulence. PurK, N⁵-carboxyaminoimidazole ribonucleotide synthetase, is a key enzyme in de novo purine biosynthesis. Its impact on virulence is distinct from the conventional production of plant cell wall–degrading enzymes: PurK promotes motility by modulating transcription of flagellar genes, acting through its three domains as an integrated unit to infect successfully. Extracellularly detected PurK suppresses callose deposition, a PAMP-triggered immunity (PTI)-like defense, while it also triggers a strong hypersensitive response and upregulates expression of PTI marker genes such as PR2 and WRKY7 when secreted into the host plant. Although PurK interacts specifically with PurE, our data indicate that PurK’s pathogenic effects operate independently of purine biosynthesis. This study reveals a reliable experimental model for more accurate assessment of microbe–plant interactions and highlights new functional roles for PurK in P. brasiliense NJAU180 pathogenesis and identifies potential targets for disease control strategies. Full article