Comprehensive elucidation of the differential physiological kale response to cytokinins under in vitro conditions.

BACKGROUND: Kale, a versatile cruciferous crop, valued for its pro-health benefits, stress resistance, and potential applications in forage and cosmetics, holds promise for further enhancement of its bioactive compounds through in vitro cultivation methods. Micropropagation techniques use cytokinins (CKs) which are characterized by various proliferative efficiency. Despite the extensive knowledge regarding CKs, there remains a gap in understanding their role in the physiological mechanisms. That is why, here we investigated the effects of three CKs - kinetin (Kin), 6-benzylaminopurine (BAP), and 2-isopentenyladenine (2iP) - on kale physiology, antioxidant status, steroidal metabolism, and membrane integrity under in vitro cultivation. RESULTS: Our study revealed that while BAP and 2iP stimulated shoot proliferation, they concurrently diminished pigment levels and photosynthetic efficiency. Heightened metabolic activity in response to all CKs was reflected by increased respiratory rate. Despite the differential burst of ROS, the antioxidant properties of kale were associated with the upregulation of guaiacol peroxidase and the scavenging properties of ascorbate rather than glutathione. Notably, CKs fostered the synthesis of sterols, particularly sitosterol, pivotal for cell proliferation and structure of membranes which are strongly disrupted under the action of BAP and 2iP possibly via pathway related to phospholipase D and lipoxygenase which were upregulated. Intriguingly, both CKs treatment spurred the accumulation of sitostenone, known for its ROS scavenging and therapeutic potential. The differential effects of CKs on brassicasterol levels and brassinosteroid (BRs) receptor suggest potential interactions between CKs and BRs. CONCLUSION: Based on the presented results we conclude that the effect evoked by BAP and 2iP in vitro can improve the industrial significance of kale because this treatment makes possible to control proliferation and/or biosynthesis routes of valuable beneficial compounds. Our work offers significant insights into the nuanced effects of CKs on kale physiology and metabolism, illuminating potential avenues for their application in plant biotechnology and medicinal research.

Long-term organogenic callus cultivation of Ranunculus illyricus L.: a blueprint for sustainable ex situ conservation of the species in urban greenery.

The growing trend of introducing wild plant species into urban environments necessitates the identification of novel species adapted to prevailing conditions. A promising reservoir of such species may be xerothermic communities where Ranunculus illyricus occurs. This study aimed to establish a micropropagation protocol for R. illyricus using indirect organogenesis. The protocol includes initiation of culture from various explants, callus proliferation, shoot regeneration, multiplication, and concurrent rooting. Callus appeared on most types of vegetative explants tested, but stolons were considered the best due to their good availability, high disinfection (85%), and robust callus production (maximum increase - 363.1%). The growth rate of the callus fresh matter (CFM) obtained from stolons was calculated. Greater CFM was obtained on the medium with the supplemented picloram 8.0 mg L- 1 with kinetin 5.0 mg L- 1 and in second part of experiment on medium with the addition of 2,4-D (2,4-dichlorophenoxyacetic acid) 2.0 mg L- 1 alone or picloram 6.0 mg L- 1 with kinetin 8.0 mg L- 1. Shoot organogenesis was observed on macronutrients B5 (Gamborg medium), micronutrients MS (Murashige and Skoog) medium with the addition of 2.0 mg L- 1 IBA (indole-3-butyric acid) and 4.0 mg L- 1 BAP (6-benzylaminopurine). To document the process of callus differentiation, microscopic preparations were prepared. Subsequently, the regenerated plants underwent acclimatisation and their growth in an ex situ collection was monitored over three growing seasons. In particular, in vitro-origin plants exhibited developmental patterns similar to those of their seed-origin counterparts. The incorporation of R. illyricus into urban landscapes not only increases aesthetic appeal, but also ensures the preservation of valuable genetic resources for this rare species, potentially contributing to effective ex situ conservation in the future. This marks the first scientific report on in vitro cultures of R. illyricus.

Deciphering the interaction of bacteria inoculants with the recipient endophytic community in grapevine micropropagated plants.

Engineering the plant microbiome with beneficial endophytic bacteria can improve the growth, health, and productivity of the holobiont. Here, we administered two beneficial bacterial strains, Kosakonia VR04 sp. and Rhizobium GR12 sp., to micropropagated grapevine cuttings obtained via somatic embryogenesis. While both strains colonized the plant endosphere, only Rhizobium GR12 sp. increased root biomass under nutritional-deficit conditions, as supported by the plant growth promotion traits detected in its genome. Phylogenetic and co-occurrence analyses revealed that the plant native bacterial community, originally dominated by Streptococcaceae and Micrococcaceae, dramatically changed depending on the inoculation treatments, as invading strains differently affected the relative abundance and the interactions of pre-existing taxa. After 30 days of plantlets' growth, Pantoea became a predominant taxon, and considering untreated plantlets as references, Rhizobium sp. GR12 showed a minor impact on the endophytic bacterial community. On the other hand, Kosakonia sp. VR04 caused a major change in community composition, suggesting an opportunistic colonization pattern. Overall, the results corroborate the importance of preserving the native endophytic community structure and functions during plant microbiome engineering.IMPORTANCEA better comprehension of bacterial colonization processes and outcomes could benefit the use of plant probiotics in the field. In this study, we applied two different beneficial bacteria to grapevine micropropagated plantlets and described how the inoculation of these strains impacts endophytic microbiota assembly. We showed that under nutritional deficit conditions, the response of the receiving endophytic bacterial communities to the invasion of the beneficial strains related to the manifestation of plant growth promotion effects by the inoculated invading strains. Rhizobium sp. GR12 was able to preserve the native microbiome structure despite its effective colonization, highlighting the importance of the plant-endophyte associations for the holobiont performance. Moreover, our approach showed that the use of micropropagated plantlets could be a valuable strategy to study the interplay among the plant, its native microbiota, and the invader on a wider portfolio of species besides model plants, facilitating the application of new knowledge in agriculture.

Unveiling the silver lining: examining the effects of biogenic silver nanoparticles on the growth dynamics of in vitro olive shoots.

The current study aimed to evaluate the effects of biogenic silver nanoparticles (AgNPs) on growth behavior and leaf anatomy of in vitro growing shoots of 'Picual' and 'Dolce' olive cultivars. Biosynthesis of AgNPs was carried out using the cell-free filtrate of Fusarium oxysporum. The dimension and shape of the synthesized AgNPs have been analyzed using spectroscopy and topography analysis tools, confirming that the biosynthesis of AgNPs is a crystalline nanostructure with an average particle size of 37 nm. The shoots of the selected olive cultivars were cultured on Rugini olive medium-supplemented AgNPs at 0, 10, 20, and 30mg L- 1. The effect of genotypes on shoot multiplication was significant, 'Picual' recorded higher values of shoot growth parameters compared with 'Dolce' cultivar. Adding AgNPs to the culture medium significantly affected the growth of in vitro olive shoots. AgNPs at 20 and 30mg L- 1 produced higher values of the number of shoots, shoot length, and leaf number of Picual cv. compared with the control treatments, but the higher AgNPs concentration harmed the growth parameters of Dolce cv. and recorded lower growth values compared with the lower concentration (10mg L- 1). AgNPs had a significant effect on leaf morphology and their anatomical structure. The current results showed that the stimulatory effect of AgNPs on shoot growth of in vitro olive shoots is highly dependent on plant genotype and nanoparticle concentration.

Genome-wide identification and characterization of wall-associated kinases, molecular docking and polysaccharide elicitation of monoterpenoid indole alkaloids in micro-propagated Catharanthus roseus.

Wall-associated kinases (WAKs) are a unique family of proteins that are predominantly localized on the plasma membrane and simultaneously bound to the cell wall. WAKs play a pivotal role in signal transduction to regulate growth, defense, and response to environmental stimuli in plants. These kinases have been identified and characterized in various plant species, however, similar information for Catharanthus roseus is scarce. C. roseus is an evergreen ornamental plant that produces a repertoire of biologically active compounds. The plant is best characterized for the production of antineoplastic monoterpenoid indole alkaloids (MIAs) namely vinblastine and vincristine. Owing to the diverse composition of phytochemicals, C. roseus is known as a "model non-model" plant for secondary metabolite research. Genome analyses showed 37 putative CrWAK genes present in C. roseus, largely localized on the plasma membrane. Phylogenetic analysis revealed six clusters of CrWAKs. Diverse cis-acting elements, including those involved in defense responses, were identified on the promotor regions of CrWAK genes. The highest binding affinity (- 12.6 kcal/mol) was noted for CrWAK-22 against tri-galacturonic acid. Tri-galacturonic acid stimulated 2.5-fold higher production of vinblastine, sixfold upregulation of the expression of ORCA3 transcription factor, and 6.14-fold upregulation of CrWAK-22 expression. Based on these results it was concluded that the expression of CrWAK genes induced by biotic elicitors may have an important role in the production of MIAs. The current findings may serve as a basis for functional characterization and mechanistic explanation of the role of CrWAK genes in the biosynthesis of MIAs upon elicitation.

Biosolids Treated as a Nutritional Alternative for in vitro Culture of Bowdichia Virgilioides Kunth.

The safe management of sewage waste is a current concern due to population growth and waste production. Biosolids, derived from sewage sludge treatment, are globally used as organic fertilizers, aligning with Sustainable Development Goal 6 for resource recycling. However, biosafety concerns arise due to the presence of metals and microplastics in biosolids, potentially impacting soil and water. This study investigated biosolids' use for in vitro cultivation of Bowdichia virgilioides Kunth. Results indicate that while biosolids can replace traditional nutritional media, balancing their concentration is crucial for optimizing plant growth. The WPM (Wood Plat Medium) remains essential for in vitro cultivation, but substituting it with biosolids at concentrations of up to 2 g L- 1 is feasible, providing similar plant development compared to the WPM medium. However, when combined, there is a complex and challenging interaction between biosolids and the culture medium.

Prediction and optimization of indirect shoot regeneration of Passiflora caerulea using machine learning and optimization algorithms.

BACKGROUND: Optimization of indirect shoot regeneration protocols is one of the key prerequisites for the development of Agrobacterium-mediated genetic transformation and/or genome editing in Passiflora caerulea. Comprehensive knowledge of indirect shoot regeneration and optimized protocol can be obtained by the application of a combination of machine learning (ML) and optimization algorithms. MATERIALS AND METHODS: In the present investigation, the indirect shoot regeneration responses (i.e., de novo shoot regeneration rate, the number of de novo shoots, and length of de novo shoots) of P. caerulea were predicted based on different types and concentrations of PGRs (i.e., TDZ, BAP, PUT, KIN, and IBA) as well as callus types (i.e., callus derived from different explants including leaf, node, and internode) using generalized regression neural network (GRNN) and random forest (RF). Moreover, the developed models were integrated into the genetic algorithm (GA) to optimize the concentration of PGRs and callus types for maximizing indirect shoot regeneration responses. Moreover, sensitivity analysis was conducted to assess the importance of each input variable on the studied parameters. RESULTS: The results showed that both algorithms (RF and GRNN) had high predictive accuracy (R2 > 0.86) in both training and testing sets for modeling all studied parameters. Based on the results of optimization process, the highest de novo shoot regeneration rate (100%) would be obtained from callus derived from nodal segments cultured in the medium supplemented with 0.77 mg/L BAP plus 2.41 mg/L PUT plus 0.06 mg/L IBA. The results of the sensitivity analysis showed the explant-dependent impact of exogenous application of PGRs on indirect de novo shoot regeneration. CONCLUSIONS: A combination of ML (GRNN and RF) and GA can display a forward-thinking aid to optimize and predict in vitro culture systems and consequentially cope with several challenges faced currently in Passiflora tissue culture.

Biotechnology of Passiflora edulis: role of Agrobacterium and endophytic microbes.

Two forms of the genus Passiflora, belonging to the Passifloraceae family, are commonly called yellow and purple passion. These perennial woody climbers are found in the cooler regions at higher altitudes and in lowlands of tropical areas. The presence of alkaloids, terpenes, stilbenes, flavonoids, glycosides, carotenoids, etc. in different parts of the plant provides several pharmacological properties. Because of the various uses in foods and pharmaceuticals, in vitro propagation of this genus has been performed hugely and is of great interest to researchers. From different explants via direct organogenesis under controlled aseptic conditions, callus, root, shoot, and somatic embryos are induced successfully. Different PGRs are augmented in the media for the rapid multiplication or organogenesis, especially, the high ratio of cytokinin and auxin in the basal media efficiently regenerates the shoot and root respectively. The in vitro regenerated plantlets are then acclimatized and hardened properly before transferring to the field conditions. Thus, the present first of its kind review on P. edulis exclusively encompasses the wide applications of biotechnology for this species alongside its organogenesis, embryogenesis, cytology, and endophytic microbes with special emphasis on the role of genetic transformation studies mediated by Agrobacterium sp. KEY POINTS: • Critical assessment on in vitro biotechnology in P. edulis. • Agrobacterium-mediated transformation in P. edulis. • Role of endophytic microbes in P. edulis.

Biotechnological interventions and production of galanthamine in Crinum spp.

Genus Crinum L. is a member of the Amaryllidaceae family having beautiful, huge, ornamental plants with umbels of lily-like blooms that are found in tropical and subtropical climates all over the world. For thousands of years, Crinum has been used as a traditional medicine to treat illnesses and disorders. Numerous distinct alkaloids of the Amaryllidaceae group, whose most well-known properties include analgesic, anticholinergic, antitumor, and antiviral, have recently been discovered by phytochemical analyses. However, because of decades of overexploitation for their economically significant bioactive ingredients and poor seed viability and germination rates, these plants are now threatened in their native environments. Because of these factors, researchers are investigating micropropagation techniques to optimize phytochemicals in vitro. This review's objective is to offer details on the distribution, phytochemistry, micropropagation, in vitro galanthamine synthesis, and pharmacology which will help to design biotechnological techniques for the preservation, widespread multiplication, and required secondary metabolite production from Crinum spp. KEY POINTS: • Botanical description and phytochemical profile of Crinum spp. • In vitro micropropagation method of Crinum sp. • Bioactive compound galanthamine isolation techniques and its pharmacological properties.

Biotechnological and endophytic-mediated production of centellosides in Centella asiatica.

In vitro culture of a plant cell, tissue and organ is a marvellous, eco-friendly biotechnological strategy for the production of phytochemicals. With the emergence of recent biotechnological tools, genetic engineering is now widely practiced enhancing the quality and quantity of plant metabolites. Triterpenoid saponins especially asiaticoside and madecassoside of Centella asiatica (L.) Urb. are popularly known for their neuroprotective activity. It has become necessary to increase the production of asiaticoside and madecassoside because of their high pharmaceutical and industrial demand. Thus, the review aims to provide efficient biotechnological tools along with proper strategies. This review also included a comparative analysis of various carbon sources and biotic and abiotic elicitors. The vital roles of a variety of plant growth regulators and their combinations have also been evaluated at different in vitro growth stages of Centella asiatica. Selection of explants, direct and callus-mediated organogenesis, root organogenesis, somatic embryogenesis, synthetic seed production etc. are also highlighted in this study. In a nutshell, this review will present the research outcomes of different biotechnological interventions used to increase the yield of triterpenoid saponins in C. asiatica. KEY POINTS: • Critical and updated assessment on in vitro biotechnology in C. asiatica. • In vitro propagation of C. asiatica and elicitation of triterpenoid saponins production. • Methods for mass producing C. asiatica.

Approaches for in vitro propagation and production of plumbagin in Plumbago spp.

The genus Plumbago (family Plumbaginaceae), commonly known as leadwort, is a sub-tropical shrub that produces secondary metabolite plumbagin, which is employed by pharmaceutical companies and in clinical research. Plumbagin is a potent pharmaceutical because of its anti-microbial, anti-malarial, antifungal, anti-inflammatory, anti-carcinogenic, anti-fertility, anti-plasmodium, antioxidant, anti-diabetic, and other effects. This review documents the biotechnological innovations used to produce plumbagin. The use of modern biotechnological techniques can lead to a variety of benefits, including better yield, increased extraction efficiency, mass production of plantlets, genetic stability, increased biomass, and more. Large-scale in vitro propagation is necessary to minimize over-exploitation of the natural population and allow the use of various biotechnological techniques to improve the plant species and secondary metabolite production. During in vitro culture, optimum conditions are requisites for explant inoculation and plant regeneration. In this review, we provide information on various aspects of plumbagin, depicting its structure, biosynthesis, and biotechnological aspects (both conventional and advanced) along with the future prospects. KEY POINTS: • Critical assessment on in vitro biotechnology in Plumbago species • In vitro propagation of Plumbago and elicitation of plumbagin • Biosynthesis and sustainable production of plumbagin.

Pitaya Nutrition, Biology, and Biotechnology: A Review.

Pitaya (Hylocereus spp.) is a member of the cactus family that is native to Central and South America but is now cultivated throughout the sub-tropical and tropical regions of the world. It is of great importance due to its nutritional, ornamental, coloring, medicinal, industrial, and high consumption values. In order to effectively utilize and develop the available genetic resources, it is necessary to appreciate and understand studies pertaining to the usage, origin, nutrition, diversity, evaluation, characterization, conservation, taxonomy, and systematics of the genus Hylocereus. Additionally, to gain a basic understanding of the biology of the plant, this review has also discussed how biotechnological tools, such as cell and tissue culture, micropropagation (i.e., somatic embryogenesis, organogenesis, somaclonal variation, mutagenesis, androgenesis, gynogenesis, and altered ploidy), virus-induced gene silencing, and molecular marker technology, have been used to enhance pitaya germplasm.

Somaclonal Variation-Advantage or Disadvantage in Micropropagation of the Medicinal Plants.

Cell and tissue plant cultures are used either to save vulnerable species from extinction or to multiply valuable genotypes, or both, and are widely applied for economically important plant species. For medicinal plants, the use of in vitro technologies for the production of secondary metabolites and pathogen-free plants has been greatly developed. Two opposite aspects characterize the in vitro micropropagation of medicinal plants: maintaining genetic fidelity for the perpetuation and preservation of elites, and the identification and exploitation of somaclonal variations associated with new, useful traits. A balance between what is advantageous and what is undesirable is necessary, and this implies the identification of somaclonal variability at all levels, from the phenotypic to molecular ones. This review addresses the somaclonal variation arising from the in vitro multiplication of medicinal plants from three perspectives: cytogenetics, genetics, and epigenetics. The possible causes of the appearance of somaclones, the methods for their identification, and the extent to which they are desirable are presented comparatively for different plant species with therapeutic properties. The emphasis is on the subtle changes at the genetic and epigenetic level, as it results from the application of methods based on DNA markers.

Rindera graeca (A. DC.) Boiss. & Heldr. (Boraginaceae) In Vitro Cultures Targeting Lithospermic Acid B and Rosmarinic Acid Production.

The in vitro cultures of Rindera graeca, a rare endemic plant, were developed as a sustainable source of phenolic acids. Various shoot and root cultures were established and scaled up in a sprinkle bioreactor. A multiplication rate of 7.2 shoots per explant was achieved. HPLC-PDA-ESI-HRMS analysis revealed the presence of rosmarinic acid (RA) and lithospermic acid B (LAB) as the main secondary metabolites in both the shoot and root cultures. The maximum RA (30.0 ± 3.2 mg/g DW) and LAB (49.3 ± 15.5 mg/g DW) yields were determined in root-regenerated shoots. The strongest free radical scavenging activity (87.4 ± 1.1%), according to 2,2-diphenyl-1-picrylhydrazyl-hydrate assay, was noted for roots cultivated in a DCR medium. The highest reducing power (2.3 µM ± 0.4 TE/g DW), determined by the ferric-reducing antioxidant power assay, was noted for shoots cultivated on an SH medium containing 0.5 mg/L 6-benzylaminopurine. A genetic analysis performed using random amplified polymorphic DNA and start codon targeted markers revealed genetic variation of 62.8% to 96.5% among the investigated shoots and roots. This variability reflects the capacity of cultivated shoots and roots to produce phenolic compounds.

Molecular characterization of vermicompost-derived IAA-releasing bacterial isolates and assessment of their impact on the root improvement of banana during primary hardening.

The hardening step of micropropagation is crucial to make the in vitro raised plants mature and further enhancing their survivability in the external environment. Auxin regulates various root physiological parameters in plant systems. Therefore, the present study aimed to assess the impact of three vermicompost-derived IAA-releasing microbial strains, designated S1, S2, and S3, as biofertilizers on in vitro raised banana plantlets during primary hardening. The High-Performance Thin-Layer Chromatography (HPTLC) analysis of these strains revealed a higher IAA content for S1 and S2 than that of S3 after 144 h of incubation. In total, seven different treatments were applied to banana plantlets, and significant variations were observed in all plant growth parameters for all treatments except autoclaved cocopeat (100%) mixed with autoclaved vermicompost (100%) at a 1:1 ratio. Among these treatments, the application of S3 biofertilizer: autoclaved cocopeat (1:1), followed by S2 biofertlizer: autoclaved cocopeat (1:1), was found to be better than other treatments for root numbers per plant, root length per plant, root volume, and chlorophyll content. These findings have confirmed the beneficial effects of microbial strains on plant systems and propose a link between root improvement and bacterial auxin. Further, these strains were identified at the molecular level as Bacillus sp. As per our knowledge, this is the first report of Bacillus strains isolated from vermicompost and applied as biofertilizer along with cocopeat for the primary hardening of banana. This unique approach may be adopted to improve the quality of plants during hardening, which increases their survival under abiotic stresses.

Modeling and optimizing in vitro percentage and speed callus induction of carrot via Multilayer Perceptron-Single point discrete GA and radial basis function.

BACKGROUND: Callus induction is the first step in optimizing plant regeneration. Fit embryogenesis and shooting rely on callus induction. In addition, using artificial intelligence models in combination with an algorithm can be helpful in the optimization of in vitro culture. The present study aimed to evaluate the percentage and speed of callus induction optimization in carrot with a Multilayer Perceptron-Single point discrete genetic algorithm (GA). MATERIALS AND METHODS: In this study, the outputs included callus induction percentage and speed, while inputs were different types and concentrations of plant growth regulator (0. 5, 0.2 mg/l 2,4-D, 0.3, 0.2, 0.5 mg/l BAP, 1, 0.2 mg/l Kin, and 2 mg/l NAA), different explants (shoot, root, leaf, and nodal), a different concentration compound of MS medium (1 × MS, 4× MS, and 8× MS) and time of sampling. The data were obtained in the laboratory, and multilayer perceptron (MLP) and radial basis function (RBF), two well-known ANNs, were employed to model. Then, GA was used for optimization, and sensitivity analysis was performed to indicate the inputs' importance. RESULTS: The results showed that MLP had better prediction efficiency than RBF. Based on the results, R2 in training and testing data was 95 and 95% for the percentage of callus induction, while it was 94 and 95% for the speed of callus induction, respectively. In addition, a concentration compound of MS had high sensitivity, while times of sampling had low sensitivity. Based on the MLP-Single point discrete GA, the best results were obtained for shoot explants, 1× MS media, and 0.5 mg/l 2, 4-D + 0.5 mg/l BAP. Further, a non-significant difference was observed between the test result and predicted MLP. CONCLUSIONS: Generally, MLP-Single point discrete GA is considered a potent tool for predicting treatment and fit model results used in plant tissue culture and selecting the best medium for callus induction.

Modulation of physiological and biochemical traits of two genotypes of Rosa damascena Mill. by SiO2-NPs under In vitro drought stress.

BACKGROUND: Drought is a major abiotic stress that restricts plant growth and efficiency although some nutrients such as silicon improve drought tolerance by regulating the biosynthesis and accumulating some osmolytes. In this regard, a completely randomized factorial design was performed with three factors including two genotypes ('Maragheh' and 'Kashan'), three concentrations of silicon dioxide nanoparticles (SiO2-NPs) (0, 50, and 100 mg L- 1), and five concentrations of PEG (0, 25, 50, 75, and 100 g L- 1) with three replications. RESULTS: The findings showed that drought stress decreased protein content and it was improved by SiO2-NPs, so the genotype of 'Maragheh' treated with 100 mg L- 1 SiO2-NPs had the highest protein content. Under severe drought stress, had a higher membrane stability index (MSI) than 'Kashan', and the 'Maragheh' explants subjected to 100 mg L- 1 SiO2-NPs exhibited the uppermost MSI. The explants supplemented with 100 mg L- 1 SiO2-NPs sustained their photosynthetic parameters more in comparison with other treatments under drought stress conditions and as well as 100 mg L- 1 SiO2-NPs showed higher content of protein and proline of 'Maragheh' than 'Kashan'. Drought stress reduced Fm, Fv/Fm, and Fv, while SiO2-NPs treatment enhanced these parameters. SiO2-NPs also improved water deficit tolerance by enhancing the activity of antioxidant enzymes such as catalase (CAT), peroxidase (POD), guaiacol peroxidase (GPX), and superoxide dismutase (SOD) and reducing lipid peroxidation and H2O2 concentration. CONCLUSIONS: According to the findings, the genotype 'Maragheh' was more tolerance to drought stress than 'Kashan' by improving water balance, antioxidant enzyme activities, and membrane stability as it was obtained from the unpublished previous evaluation in in vivo conditions and we concluded based on these results, in vitro culture can be used for drought screening in Damask rose plants. The results of the current study revealed that the induced drought stress by polyethylene glycol (PEG) in two Damask rose genotypes was ameliorated with SiO2-NPs and the tolerance genotypes were better than the sensitive ones in response to SiO2-NPs treatment.

Using plant growth-promoting microorganisms (PGPMs) to improve plant development under in vitro culture conditions.

MAIN CONCLUSION: The use of beneficial microorganisms improves the performance of in vitro - cultured plants through the improvement of plant nutrition, the biological control of microbial pathogens or the production of phytohormones that promote plant growth and development. Plant in vitro culture techniques are highly useful to obtain significant amounts of true-to-type and disease-free plant materials. One of these techniques is clonal micropropagation which consists on the establishment of shoot tip cultures, shoot multiplication, in vitro rooting and acclimatization to ex vitro conditions. However, in some cases, the existence of recalcitrant genotypes, with a compromised multiplication and rooting ability, or the difficulties to overcome the overgrowth of endophytic contaminations might seriously limit its efficiency. In this sense, the establishment of beneficial interactions between plants and plant growth-promoting microorganisms (PGPMs) under in vitro culture conditions might represent a valuable approach to efficiently solve those restrictions. During the last years, significant evidence reporting the use of beneficial microorganisms to improve the yield of in vitro multiplication or rooting as well as their acclimatization to greenhouse or soil conditions have been provided. Most of these positive effects are strongly linked to the ability of these microorganisms to provide in vitro plants with nutrients such as nitrogen or phosphorous, to produce plant growth regulators, to control the growth of pathogens or to mitigate stress conditions. The culture of A. thaliana under aseptic conditions has provided high-quality knowledge on the root development signaling pathways, involving hormones, triggered in the presence of PGPMs. Overall, the present article offers a brief overview of the use of microorganisms to improve in vitro plant performance during the in vitro micropropagation stages, as well as the main mechanisms of plant growth promotion associated with these microorganisms.

In vitro drought stress and drought-related gene expression in banana.

BACKGROUND: Banana is largely grown in tropical and subtropical climates. It is rich in various food components and has quite a high economic value. Unavailable ecological and agricultural conditions cause quantitative and qualitative losses in banana cultivation. Along with global climate change, drought stress is becoming prominent day by day. METHODS AND RESULTS: Micropropagation and rooting performance of Azman and Grand Naine banana cultivars were investigated under in vitro drought stress conditions. The expression levels of four different genes of CDPK gene family in leaf and root tissues of the rooted plants were determined with the use of qRT-PCR. Greater expression levels of four MaCDPK genes were seen in Azman cultivar than in Grand Naine cultivar. MaCDPK9 and MaCDPK21 had greater expression levels in root tissue and MaCDPK1 and MaCDPK40 genes in leaf tissues. CONCLUSIONS: Response of different banana cultivars to in vitro drought stress was determined in this study. The expression levels of the genes of CDPK gene family with a significant role in drought stress had significant contributions in elucidation of banana plant response to drought stress.

In vitro propagation and secondary metabolite production in Gloriosa superba L.

Gloriosa superba L., commonly known as "gloriosa lily," "glory lily," and "tiger claw," is a perennial climber in the Liliaceae family. This plant is used in African and Southeast Asian cultures as an ayurvedic medicinal herb to treat various health conditions. Its main bioactive component is colchicine, which is responsible for medicinal efficacies as well as poisonous properties of the plant. A high market demand, imprudent harvesting of G. superba from natural habitat, and low seed setting have led scientists to explore micropropagation techniques and in vitro optimization of its phytochemicals. Plant growth regulators have been used to induce callus, root, and shoot organogenesis, and somatic embryogenesis in vitro. This review is aimed at presenting information regarding the occurrence, taxonomic description, phytochemistry, micropropagation, in vitro secondary metabolite, and synthetic seed production. The data collected from the existing literature, along with an analysis of individual study details, outcomes, and variations in the reports, will contribute to the development of biotechnological strategies for conservation and mass propagation of G. superba. KEY POINTS: • Latest literature on micropropagation of Gloriosa superba. • Biotechnological production and optimization of colchicine. • Regeneration, somatic embryogenesis, and synthetic seed production.