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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]

This study was conducted during two winter seasons 2020-2019 and 2021-2020 at the College of Agricultural Engineering Sciences-University of Baghdad (Al-Jadriya). To improve the efficiency and productivity of the flower growth, yield, and essential oil characteristic of cumin (Cuminum cyminum L.). The experiment included two-factors, the first with four levels of bio-fertilizers (without vaccination, Pseudomonas fluorescens, Azospirillum brasilense, and mixture between vaccination), while the second with a combination of five levels that included two treatments (15 and 30 ml L-1 ) for each of coconut endosperm fluid and tryptophan with one metering treatment for both (sprayed with distilled water). Randomized complete block design (RCBD) was used in a spilt-plot design with three replications. The results showed that all studied traits were affected by the study factors for both seasons, as the plants treated with the spray combination (30 ml L-1 each) with mixture between vaccination gave superiority in most of the within, and the interaction effect between the study factors was significant compared to the plants uninoculated and unsprayed for both seasons. [ABSTRACT FROM AUTHOR]

In order to explore the response mechanism of Passiflora edulis Sims to drought stress, the changes in morphological and physiological traits of Passiflora edulis Sims under different drought conditions were studied. A total of 7 germplasm resources of Passiflora edulis Sims were selected and tested under drought stress by the pot culture method under 4 treatment levels: 75%-80% (Control, CK) of maximum field water capacity, 55%-60% (Light Drought, LD) of maximum field water capacity, i.e., mild drought, 40%-45% (Moderate Drought, MD) of maximum field water capacity, i.e., moderate drought and 30%-35% (Severe Drought, SD) of maximum field water capacity, i.e., severe drought. On the 40th day of drought treatment, 13 indices, including seedling growth morphology, physiology, and biochemistry, were measured. The results showed that under drought stress, the height and ground diameter of P. edulis Sims gradually decreased with increasing drought stress, and there were significant differences in seedling height and ground diameter among the treatments. Drought stress significantly inhibited the growth of seven P. edulis Sims varieties. The contents of soluble sugar (SS), soluble protein (SP), proline (Pro), and other substances in P. edulis Sims basically increased with increasing drought stress. With the aggravation of drought stress, the malondialdehyde (MDA) content of P. edulis Sims tended to increase to different degrees, the superoxide dismutase (SOD) activity and peroxidase (POD) activity both tended to increase at first and then decrease, and the change in catalase (CAT) activity mostly showed a gradual increasing trend. The contents of endogenous hormones in P. edulis Sims significantly differed under different degrees of drought stress. With the aggravation of drought stress, the abscisic acid (ABA) content of P. edulis Sims tended to increase, whereas the contents of gibberellin (GA), indoleacetic acid (IAA), and zeatin nucleoside (ZR) exhibited a downward trend. A comprehensive evaluation of the drought resistance of seven P. edulis Sims varieties was conducted based on the principal component analysis method, and the results showed that the drought resistance decreased in the order XH-BL > XH-TWZ > TN1 > GH1 > ZJ-MT > LP-LZ > DH-JW. [ABSTRACT FROM AUTHOR]

The cytokinin oxidase/dehydrogenase (CKX) enzyme is essential for controlling the fluctuating levels of endogenous cytokinin (CK) and has a significant impact on different aspects of plant growth and development. Nonetheless, there is limited knowledge about CKX genes in tomato (Solanum lycopersicum L.). Here we performed genome-wide identification and analysis of nine SlCKX family members in tomatoes using bioinformatics tools. The results revealed that nine SlCKX genes were unevenly distributed on five chromosomes (Chr.1, Chr.4, Chr.8, Chr.10, and Chr.12). The amino acid length, isoelectric points, and molecular weight of the nine SlCKX proteins ranged from 453 to 553, 5.77 to 8.59, and 51.661 to 62.494 kD, respectively. Subcellular localization analysis indicated that SlCKX2 proteins were located in both the vacuole and cytoplasmic matrix; SlCKX3 and SlCKX5 proteins were located in the vacuole; and SlCKX1, 4, 6, 7, 8, and 9 proteins were located in the cytoplasmic matrix. Furthermore, we observed differences in the gene structures and phylogenetic relationships of SlCKX proteins among different members. SlCKX1-9 were positioned on two out of the three branches of the CKX phylogenetic tree in the multispecies phylogenetic tree construction, revealing their strong conservation within phylogenetic subgroups. Unique patterns of expression of CKX genes were noticed in callus cultures exposed to varying concentrations of exogenous ZT, suggesting their roles in specific developmental and physiological functions in the regeneration system. These results may facilitate subsequent functional analysis of SlCKX genes and provide valuable insights for establishing an efficient regeneration system for tomatoes. [ABSTRACT FROM AUTHOR]

Lilium chalcedonicum L., a bulbous perennial endemic to the Balkans, is recognized for its considerable ornamental potential. In this study, seeds were gathered from a wild population and subjected to surface disinfection. Subsequently, they were placed in Petri dishes containing a half-strength Murashige and Skoog (MS) nutrient substrate (MS/2), with temperature conditions at 15 °C and 20 °C, followed by cycles of 5 °C and return to 15 °C and 20 °C, respectively. The in vitro-cultivated seedlings were then transplanted for further growth in MS medium enriched with either 30 g L-1 or 60 g L-1 sucrose and 0.1 mg L-1 6-N-benzyladenine (BA). In the following stage, the resulting bulblets were separated and cultivated in MS/2, either without hormones (Hf) or with BA at concentrations of 0.2 mg L-1, 0.5 mg L-1, or 1 mg L-1. Moreover, the combined influence of 1-naphthaleneacetic acid (NAA) at a concentration of 1.0 mg L-1 and 0.2 mg L-1 BA was examined. This stage was succeeded by a further division of the bulblets, and the explants were cultured in Hf, MS/2 or with the inclusion of 0.5 mg L-1 BA or a combination of BA and NAA at ratios of 0.2/1 and 0.5/0.05 mg L-1; zeatin at 0.5 mg L-1 was also used, combined with 0.05 mg L-1 NAA. Notably, all seeds exhibited a 100% germination rate following alternating temperature regimes including periods of low temperature. During the initial cultivation phase, each seedling gave rise to two bulblets measuring 0.6 cm in diameter. Subsequent subcultures on Hf substrates and those containing BA without NAA, resulted in the highest number of bulblets (1.6-2.2 bulbs/plant) of the largest diameter (0.8-0.9 cm). Particularly noteworthy was the substantial increase in the average number of produced bulblets during the subsequent subcultures (multiplication stage), where 16.9 bulbs were formed in MS/2 medium containing 0.5 mg L-1 BA, with a median diameter of 1.7 cm. [ABSTRACT FROM AUTHOR]

Strains of the ascomycetous yeast Metschnikowia pulcherrima isolated from the internal tissues of fruits were evaluated for phytohormonal activity. IAA production in the culture liquid was determined by the chromatographic method (HPLC-UV). The production of the phytohormones zeatin and gibberellin (GA3) in the culture liquid was determined by a chromatographic method using a quadrupole time-of-flight mass spectrometry detector (Q- TOF LC / MS). IAA and zeatin were detected in the culture liquid of all strains studied. Synthesis of gibberellin (GA3) was detected in only 5 of 18 strains examined. On average, the strains showed the highest activity in the synthesis of IAA (6.668 µg/mL and 2.135 mg/g). Zeatin content was 3 orders of magnitude lower (0.365 ng/mL and 0.129 µg/g) and GA3 content was 4 orders of magnitude lower (0.076 ng/mL and 0.027 µg/g). According to our results, the yeast M. pulcherrima is not an active producer of zeatin and GA3 in amounts relevant to the plant. On the other hand, the average level of IAA synthesis detected in M. pulcherrima strains in this study is within the range of concentrations that can stimulate plant development and growth. Thus, endophytic strains of M. pulcherrima that produce plant-relevant levels of IAA could be improved to increase their synthesis ability and used as plant growth promoters in agricultural crops. [ABSTRACT FROM AUTHOR]

Potato (Solanum tuberosum L.), belonging to Solanaceae family, globally ranks as the fourth-largest food (vegetable) crop. In order to sustain the supply of quality propagules, a large-scale in vitro shoot, microtuber and root development protocol was successfully established for potato cv. Badami alu, for the first time. Initially, the tuber sprout explants were inoculated in Murashige and Skoog (MS) basal medium individually with 0.5–1.5 mg/l 6-benzyladenine, kinetin, meta-topolin (mT) and zeatin (Zea) for regeneration. The earliest (~ 3 days) shoot initiation with maximum number (~ 9) and length (81 mm) shoots were recorded in MS medium fortified with 1 mg/l mT after 4 weeks of growth period. The earliest (44 days) microtuber formation with maximum number (4.3) was recorded in MS medium fortified with 1 mg/l Zea after 8 weeks growth stage. On the other hand, the hierarchical clustering heat map, network plot, and principal component analyses illustrated the association among cytokinins (sources and concentrations) and the different growth attributes under study. In vitro-regenerated shootlets were then cultured in MS medium individually with 1–3 mg/l indole-3-acetic acid (IAA) and indole-3-butyric acid. The earliest (~ 7 days) root induction was recorded in MS medium with 1 mg/l IAA, whereas the maximum number (47) with most elongated (28.3 mm) roots were recorded in 2 mg/l IAA after 4 weeks culture period. The micropropagated plantlets were grown in cocopeat (for 1 month) followed by soil (for 2 months) under field conditions (shade net house) that resulted in 95% survival rate. Stability of ploidy level of micropropagated and successively field-grown plantlets with their mother plant was affirmed by flow cytometry, likewise, genetic fidelity was assessed for the same via inter simple sequence repeats, directed amplification of minisatellite-region DNA, start codon targeted polymorphism, and conserved DNA-derived polymorphism markers, and a 100% monomorphism was found, proving that there was no genetic variation among them. Since there is no report of non-conventional mass propagation of this cultivar to date, the present protocol will be immensely helpful for its accelerated large-scale propagation and its genetic improvement. Key message: First report on usage of meta-Topolin and zeatin for micropropagation and microtuberization followed by acclimatization and field performance of true-to-type propagules (ensured by flow cytometry and molecular markers) in potato. [ABSTRACT FROM AUTHOR]

Lilium chalcedonicum L., a bulbous perennial endemic to the Balkans, is recognized for its considerable ornamental potential. In this study, seeds were gathered from a wild population and subjected to surface disinfection. Subsequently, they were placed in Petri dishes containing a half-strength Murashige and Skoog (MS) nutrient substrate (MS/2), with temperature conditions at 15 °C and 20 °C, followed by cycles of 5 °C and return to 15 °C and 20 °C, respectively. The in vitro-cultivated seedlings were then transplanted for further growth in MS medium enriched with either 30 g L-1 or 60 g L-1 sucrose and 0.1 mg L-1 6-N-benzyladenine (BA). In the following stage, the resulting bulblets were separated and cultivated in MS/2, either without hormones (Hf) or with BA at concentrations of 0.2 mg L-1, 0.5 mg L-1, or 1 mg L-1. Moreover, the combined influence of 1-naphthaleneacetic acid (NAA) at a concentration of 1.0 mg L-1 and 0.2 mg L-1 BA was examined. This stage was succeeded by a further division of the bulblets, and the explants were cultured in Hf, MS/2 or with the inclusion of 0.5 mg L-1 BA or a combination of BA and NAA at ratios of 0.2/1 and 0.5/0.05 mg L-1; zeatin at 0.5 mg L-1 was also used, combined with 0.05 mg L-1 NAA. Notably, all seeds exhibited a 100% germination rate following alternating temperature regimes including periods of low temperature. During the initial cultivation phase, each seedling gave rise to two bulblets measuring 0.6 cm in diameter. Subsequent subcultures on Hf substrates and those containing BA without NAA, resulted in the highest number of bulblets (1.6-2.2 bulbs/plant) of the largest diameter (0.8-0.9 cm). Particularly noteworthy was the substantial increase in the average number of produced bulblets during the subsequent subcultures (multiplication stage), where 16.9 bulbs were formed in MS/2 medium containing 0.5 mg L-1 BA, with a median diameter of 1.7 cm.

All around the world, one of the leading – according to area of cultivated fields – oleic crops is soybean, which has a high demand for moisture. Given the significance of this crop and negative impact of drought on its yield, integrated research of the influence of insufficient water supply on the intensity of physiological-biochemical processes in those plants is necessary for identifying and understanding the drought-tolerance mechanisms of soybean, as well as symbiotic systems created with its participation, and also for search for ways to adapt it to this stressor. Therefore, our objective was determining the specifics of formation and functioning of the symbiotic systems of soybean and Bradyrhizobium japonicum, following treatment with succinic acid (0.01 g/L) and 24-epibrassinolide (0.00001 g/L), subject to different levels of watering. Our studies revealed that pre-sowing treatment of the seeds with a solution of 24-epibrassinolide with their subsequent inoculation with B. japonicum Т21-2 resulted in the most pronounced stimulation of formation and functioning of the symbiotic systems of soybean in the optimal growing conditions. At the same time, during water shortage, the intensity of nitrogen fixation was the highest in the plants grown from seeds that had been successively treated with the acid and the inoculant. We confirmed that water deficit led to significant increase in the overall content of phytohormones of cytokinin nature in the soybean root nodules, depending on the way the seeds were treated. However, the largest pool of cytokinins was seen in the plants that had been treated with succinic acid against the background of both optimal and insufficient water supply. Treatment of the seeds with 24-epibrassinolide caused significant excess of content of zeatin riboside over the content of zeatin during the flowering stage, whereas in the stage of pods formation it led to an opposite effect – excess of zeatin over zeatin riboside. Fourteen days-long water deficit decreased the content of chlorophylls in the leaves and grain productivity of the plants of all variants of the experiment. The use of growth regulators managed to alleviate the negative impact of stress and protect the pigment complex from ruination. Treatment of the seeds with solutions of succinic acid and 24-epibrassinolide provided the growth of soybean grain productivity regardless on water-supply level. The most efficient was 24-epibrassinolide. Therefore, use of 24-epibrassinolide for pre-sowing treatment of the soybean seeds provided formation of effective symbiotic systems with high nitrogen-fixing activity and caused a number of specific changes in the pattern of accumulation of free and complex forms of cytokinins in the root nodules of those plants. At the same time, the treatment provided the highest concentration of photosynthesis pigments in the soybean leaves, and as a result produced the greatest increase in grain productivity of plants of all the variants, regardless of levels of water supply. In turn, use of succinic acid produced the highest level of nitrogen-fixing activity in the case of the lowest number of root nodules in the conditions of insufficient water supply, and also caused significant accumulation of cytokinins in the nodules, compared with other studied variants against the background of both optimal and insufficient water supply. Therefore, it did result in increase in soybean grain productivity, but this was lower than in the plants treated with 24-epibrassinolide.

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.

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Early in the history of cytokinins, it was clear that Zea mays seeds contained not just trans-zeatin, but its nucleosides and nucleotides. Subsequently, both pods and seeds of legumes and cereal grains have been shown to contain a complex of cytokinin forms. Relative to the very high quantities of cytokinin detected in developing seeds, only a limited amount appears to have been translocated from the parent plant. Translocation experiments, and the detection of high levels of endogenous cytokinin in the maternal seed coat tissues of legumes, indicates that cytokinin does not readily cross the maternal/filial boundary, indicating that the filial tissues are autonomous for cytokinin biosynthesis. Within the seed, trans-zeatin plays a key role in sink establishment and it may also contribute to sink strength. The roles, if any, of the other biologically active forms of cytokinin (cis-zeatin, dihydrozeatin and isopentenyladenine) remain to be elucidated. The recent identification of genes coding for the enzyme that leads to the biosynthesis of trans-zeatin in rice (OsCYP735A3 and 4), and the identification of a gene coding for an enzyme (CPN1) that converts trans-zeatin riboside to trans-zeatin in the apoplast, further cements the key role played by trans-zeatin in plants. [ABSTRACT FROM AUTHOR]

Douglas maple (Acer glabrum Torr. var. douglasii (Hook.) Dippel [Aceraceae]) is a potentially valuable landscape plant that lacks efficacious asexual propagation protocols. We conducted a series of developmental experiments to evaluate basal salts, supplemental minerals, and cytokinins to optimize culture medium formulations. Three commercial formulations of basal salts were evaluated, Driver and Kuniyaki Walnut (DKW), Murashige and Skoog (MS), and Woody Plant Medium (WPM). The DKW medium was superior to the other commercially available nutrient formulations for promoting shoot growth and enhancing node production. Iron supplementation (addition of 45 mg/l) resolved issues of chlorosis associated with reduced microcutting growth and multiplication rates. Supplementation of 12.0 mg/l boric acid resolved shoot tip necrosis problems. Cytokinin optimization with respect to shoot length was evaluated in 3 experiments, in which, BA, kinetin, MT, TDZ, and zeatin were all tested at various concentrations. Autoclaved zeatin at 4 µM or MT at 2 µM were the best 2 cytokinins and concentrations for promoting shoot growth. Two zeatin sterilization methods were tested, autoclaving following addition to medium, and filter sterilizing prior to adding to post-autoclaved medium. Autoclaving media that included zeatin proved to be effective methodology, thus avoiding filter sterilization, which commonly introduces microbial contaminants into media. Overall, Douglas maple growth and development during micropropagation were optimized on DKW medium, supplemented with iron (45 mg/l) and boron (12.0 mg/l) and either 4 µM autoclaved zeatin, or with 2 µM MT. Economic efficiency is improved by using MT, rather than the much more expensive zeatin. [ABSTRACT FROM AUTHOR]

Olive (Olea europaea L.) is one of the oldest cultivated fruit species in the world. Fruits and oils of autocthonous olive varieties (native Turkish olive varieties) with unique sensory properties (taste, smell and aroma) gain importance recently. Particularly olive oil companies looking for varieties that have distinct taste, smell and aroma in their oil. Propagation of olive varieties by cuttings and grafting is very difficult and expensive, therefore it is important to find solution for easy and mass propagation. Micropropagation is particularly beneficial to propagate plants that are difficult to reproduce conventionally or to ensure virus-free plants or plants with particular qualities. In this study, in vitro micropropagation success of two autocthonous olive varieties (‘Mavi’ and ‘Guleki’) grown in the origin center of olive, Southeast Anatolia, Türkiye was investigated. Both varieties, have distinct smell, taste and aroma and are difficult to root by cuttings. The effects of three different medium OM (Olive Medium), WPM (Woody Plant Medium) and DKW (Driver-Kuniyuki Walnut Medium) and two different growth regulators BAP (6-Benzylaminopurine) and Zeatin on shoot induction (proliferation) in the in vitro micropropagation of the olive varieties were examined. Obtained shoots were later subjected to in vitro rooting and acclimatization. The highest proliferation efficiency and shoot length for both varieties were obtained with the use of 1 mg Zeatin+0.1 mg GAɜ hormone combinations on OM medium. ‘Mavi’ variety formed more roots compared to ‘Guleki’ (3.33 vs. 2.75 per shoots), and gave the highest rooting rate of 74.33% with 2 mg IBA (Indole Butyric Acid) treatment on ½ OM medium. In terms of rooting rate, Guleki gave the highest rooting (100%) on medium containing ½ OM, 0.2 mg GA3 and 4 mg IBA. 60% and 75% of the micropropagated plants of ‘Mavi’ and ‘Guleki’ varieties adapted well to the external conditions.

Simple Summary: Rhizomes are underground stems that grow horizontally from the base of the stem and confer competitive, reproductive, foraging, and regenerative advantages to plants. They are especially important for forage and turfgrasses. Different phytohormones influence the growth and development of plant rhizomes in a variety of ways. Here, we compare the phytohormonal and metabolomic profiles of rhizomes from two contrasting Kentucky bluegrass (Poa pratensis), a perennial herb with variable rhizome traits materials: multi-rhizome and few-rhizome. We found that zeatin (ZT) was abundant in the multi-rhizome material, while indole-3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA) showed the opposite trend. Metabolomics revealed that the ABC transporter pathway and the histidine metabolism pathway, both related to cytokinin, were significantly expressed in the comparison group. Rhizomes are an ideal plant trait. Our findings provide new insights into the development of perennial rhizomatous herbs and a theoretical basis for the future breeding of rhizomatous plants. Rhizome growth and development is regulated by phytohormone. However, endogenous phytohormones affect rhizome initiation, and sustained growth in perennial grass species remains elusive. In this study, we investigated the morphological characteristics and the content of indole-3-acetic acid (IAA), zeatin (ZT), gibberellic acid (GA3), and abscisic acid (ABA) in the rhizomes of two different Kentucky bluegrass. Using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), we performed metabolite analysis of two different rhizomes. In our study, the multi-rhizome Kentucky bluegrass material 'Yuzhong' had an average of 1113 rhizomes, while the few-rhizome material 'Anding' had an average of 347 rhizomes. The diameter of rhizome and length of rhizome internode in 'Yuzhong' were 1.68-fold and 1.33-fold higher than that of the 'Anding', respectively. The rhizome dry weight of 'Yuzhong' was 75.06 g, while the 'Anding' was 20.79 g. 'Yuzhong' had a higher ZT content (5.50 μg·g−1), which is 2.4-fold that of 'Anding' (2.27 μg·g−1). In contrast, the IAA, ABA, and GA3 content of rhizome were markedly higher in 'Anding' than 'Yuzhong'. Correlation analysis revealed significant correlations between ZT and ZT/ABA with the number of rhizomes, diameter of rhizome, and length of rhizome internode, whereas IAA, ABA, GA3, and IAA/ZT were opposite. In the metabolic profiles, we identified 163 differentially expressed metabolites (DEMs) (60 upregulated and 103 downregulated) in positive ion mode and 75 DEMs (36 upregulated and 39 downregulated) in negative ion mode. Histidine metabolism and ABC transporters pathways were the most significantly enriched in the positive and negative ion mode, respectively, both of which are involved in the synthesis and transport of cytokinin. These results indicate that cytokinin is crucial for rhizome development and promotes rhizome germination and growth of Kentucky bluegrass. [ABSTRACT FROM AUTHOR]

Olive (Olea europaea L.) is one of the oldest cultivated fruit species in the world. Fruits and oils of autocthonous olive varieties (native Turkish olive varieties) with unique sensory properties (taste, smell and aroma) gain importance recently. Particularly olive oil companies looking for varieties that have distinct taste, smell and aroma in their oil. Propagation of olive varieties by cuttings and grafting is very difficult and expensive, therefore it is important to find solution for easy and mass propagation. Micropropagation is particularly beneficial to propagate plants that are difficult to reproduce conventionally or to ensure virus-free plants or plants with particular qualities. In this study, in vitro micropropagation success of two autocthonous olive varieties ('Mavi' and 'Guleki') grown in the origin center of olive, Southeast Anatolia, Türkiye was investigated. Both varieties, have distinct smell, taste and aroma and are difficult to root by cuttings. The effects of three different medium OM (Olive Medium), WPM (Woody Plant Medium) and DKW (Driver-Kuniyuki Walnut Medium) and two different growth regulators BAP (6-Benzylaminopurine) and Zeatin on shoot induction (proliferation) in the in vitro micropropagation of the olive varieties were examined. Obtained shoots were later subjected to in vitro rooting and acclimatization. The highest proliferation efficiency and shoot length for both varieties were obtained with the use of 1 mg Zeatin+0.1 mg GA3 hormone combinations on OM medium. 'Mavi' variety formed more roots compared to 'Guleki' (3.33 vs. 2.75 per shoots), and gave the highest rooting rate of 74.33% with 2 mg IBA (Indole Butyric Acid) treatment on ½ OM medium. In terms of rooting rate, Guleki gave the highest rooting (100%) on medium containing ½ OM, 0.2 mg GA3 and 4 mg IBA. 60% and 75% of the micropropagated plants of 'Mavi' and 'Guleki' varieties adapted well to the external conditions. [ABSTRACT FROM AUTHOR]

Root morphology and physiology influence aboveground growth and yield formation in rice. However, root morphological and physiological differences among rice varieties with differing nitrogen (N) sensitivities and their relationship with grain yield are still unclear. In this study, rice varieties differing in N sensitivity over many years of experiments were used. A field experiment with multiple N rates (0, 90, 180, 270, and 360 kg ha-1) was conducted to elucidate the effects of N application on root morphology, root physiology, and grain yield. A pot experiment with root excision and exogenous application of 6-benzyladenine (6-BA) at heading stage was used to further verify the above effects. The findings revealed that (1) under the same N application rate, N-insensitive varieties (NIV) had relatively large root biomass (root dry weight, length, and number). Grain yield was associated with root biomass in NIV. The oxidation activity and zeatin (Z) + zeatin riboside (ZR) contents in roots obviously and positively correlated with grain yield in N-sensitive varieties (NSV), and accounted for its higher grain yield than that of NIV at lower N application rates (90 and 180 kg ha-1). (2) The root dry weight required for equal grain yield of NIV was greater than that of NSV. Excision of 1/10 and 1/8 of roots at heading stage had no discernible effect on the yield of Liangyoupeijiu (NIV), and it significantly reduced yield by 11.5% and 21.3% in Tianyouhuazhan (NSV), respectively, compared to the treatment without root excision. The decrease of filled kernels and grain weight after root excision was the primary cause for the yield reduction. Root excision and exogenous 6-BA application after root excision had little influence on the root activity of NIV. The oxidation activity and Z + ZR contents in roots of NSV decreased under root excision, and the increase in the proportion of excised roots aggravated these effects. The application of exogenous 6-BA increased the root activity of NSV and increased filled kernels and grain weight, thereby reducing yield loss after root excision. Thus, the root biomass of NIV was large, and there may be a phenomenon of "root growth redundancy." Vigorous root activity was an essential feature of NSV. Selecting rice varieties with high root activity or increasing root activity by cultivation measures could lead to higher grain yield under lower N application rates. [ABSTRACT FROM AUTHOR]

The main objective of this study was to find a best protocol for callus induction and plant regeneration of potato (Solanum tuberosum L.). The experiment was carried out in complete randomized design (CRD). Leaves and internodes of potato cv. Desiree were used as explant for callus induction and plant regeneration. Two types of callus induction media (CIM) were used, i.e. CIM1 and CIM2 with concentrations of 2, 4-D 2mg/lit and 3 mg/lit respectively. Among the two different callus induction media (CIM), CIM1 with 2mg/lit auxin (2, 4-D) showed the best results. All the internodal explants placed on CIM1 produced 100% callus while CIM2 produced 70% callus. No callus was observed from leaves on CIM1 and CIM2. After callus induction, four different types of media were used for plant regeneration, having different concentrations of cytokinin (BAP and Zeatin) i.e. RZ1.5, RZ2, RB1 and RB2. The most efficient regeneration media was RZ2, having Zeatin 2mg/lit showed early and maximum shoot formation. On average, 05 shoots per explant were observed on RZ2. No shoot formation was observed with regeneration media having BAP, i.e. RB1 and RB2. From the research work, it is concluded that auxin (2, 4-D) @ 2mg/lit and cytokinin (zeatin) @ 2mg/lit proved to be the optimum quantity for callus induction and plant regeneration in potato respectively. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the effect of three cytokines [6-benzyladenine (BA), meta-Topoline (mT), and zeatin (Z)] on the in vitro propagation of C. avellana. The culture medium used in all in vitro culture stages was McCown's Woody Plant Medium (WPM) supplemented with 100 mg/l Sequestrene 138.3% (w/v) sugar, solidified with 5 g/l. Plant agar and pH 5.8. At the initiation stage, single-node mini cuttings were inoculated on WPM medium supplemented with 2 mg/l Z, and the initiation percentage was 66.66%. The highest proliferation rate (2.21 ± 0.11) was observed on the culture medium supplemented with 4 mg/l BA followed by the culture medium supplemented with 4 mg/l Z (1.93 ± 0.03). The shortest shoots were measured on WPM medium with 4 mg/l BA, with an average length of 1.81 ± 0.08 cm, and the longest shoots (3.46 ± 0.02 cm) were obtained on WPM medium with 4 mg/l Z. The in vitro rooting percentage was 81.66 ± 0.39% when using the WPM medium with 1 mg/l Z. The rooted plants obtained in vitro showed an acclimation rate of 97.66%, and out of these, 96% survived under greenhouse conditions. [ABSTRACT FROM AUTHOR]

Early in the history of cytokinins, it was clear that Zea mays seeds contained not just trans-zeatin, but its nucleosides and nucleotides. Subsequently, both pods and seeds of legumes and cereal grains have been shown to contain a complex of cytokinin forms. Relative to the very high quantities of cytokinin detected in developing seeds, only a limited amount appears to have been translocated from the parent plant. Translocation experiments, and the detection of high levels of endogenous cytokinin in the maternal seed coat tissues of legumes, indicates that cytokinin does not readily cross the maternal/filial boundary, indicating that the filial tissues are autonomous for cytokinin biosynthesis. Within the seed, trans-zeatin plays a key role in sink establishment and it may also contribute to sink strength. The roles, if any, of the other biologically active forms of cytokinin (cis-zeatin, dihydrozeatin and isopentenyladenine) remain to be elucidated. The recent identification of genes coding for the enzyme that leads to the biosynthesis of trans-zeatin in rice (OsCYP735A3 and 4), and the identification of a gene coding for an enzyme (CPN1) that converts trans-zeatin riboside to trans-zeatin in the apoplast, further cements the key role played by trans-zeatin in plants.

In this study, adventitious organogenesis from mature tissues of 'Verna 51' and 'Fino 49' lemon cultivars has been studied, as well as their relation with endogenous cytokinins and ethylene production. Thus, nodal explants in which buds were completely removed, obtained from in vitro shoot cultures of both lemon cultivars, were cultured in regeneration media, and the regeneration rate and the explants that regenerated were recorded. Also, after regeneration, endogenous cytokinin content was analyzed, as well as the ethylene emitted by the explants of both cultivars. After 8 wk in the culture medium, the explants of 'Fino 49' were more regenerative than those of 'Verna 51'. Likewise, the endogenous content of cytokinins was globally higher in 'Verna 51', even if the levels of isopentenyladenine and isopentenyladenosine were higher in 'Fino 49'. Additionally, 'Verna 51' explants had higher concentrations of zeatin than 'Fino 49', and the same content of N6-benzyladenine and N6-benzyladenosine. In like manner, the ethylene level emitted by the explants was higher in 'Verna 51'. According to these results, the amount of endogenous cytokinins as well as the ethylene production by the explant plays an important role in the organogenesis of mature explants of C. limon. [ABSTRACT FROM AUTHOR]

The effect of commercial Hydroplus™ Actisil, coconut water, coconut milk, and pH of the WPM medium on the micropropagation of V. corymbosum 'Liberty' was studied. Three experiments were performed with different concentrations of silicon Hydroplus™ Actisil (Si), coconut water (CW), coconut milk (CM), and different pH as a stress factor. Si was applied at a concentration of 50, 100, 200 and 500 mg dm-3. The highest explant (2.02 cm) with the highest number of new shoots (1.91) and fresh weight (55.16 g) was obtained on WPM medium with the addition of Si in concentration 200 mg dm-3. In experiment 2, similar to 0.1 mg dm-3 zeatin explant growth was achieved when 15% CW was added to the WPM medium (2.13 cm). The use of CM did not have a positive effect on blueberry growth in vitro. The results of experiment 3 indicated that explants of blueberry better developed when pH was lower (5.0) with the highest number of new shoots (2.85) and fresh weight (95.67g). However, there were no significant differences in plant height between pH used. The application of 200 mg dm-3 Actisil benefits the negative effect of higher pH of the WPM medium on micropropagation of blueberry in case of plant height, fresh weight, and biochemical parameters (proline, malondialdehyde - MDA and catalase - CAT activity). [ABSTRACT FROM AUTHOR]

The effect of commercial Hydroplus™ Actisil, coconut water, coconut milk, and pH of the WPM medium on the micropropagation of V. corymbosum ‘Liberty’ was studied. Three experiments were performed with different concentrations of silicon Hydroplus™ Actisil (Si), coconut water (CW), coconut milk (CM), and different pH as a stress factor. Si was applied at a concentration of 50, 100, 200 and 500 mg dm–3. The highest explant (2.02 cm) with the highest number of new shoots (1.91) and fresh weight (55.16 g) was obtained on WPM medium with the addition of Si in concentration 200 mg dm–3. In experiment 2, similar to 0.1 mg dm–3 zeatin explant growth was achieved when 15% CW was added to the WPM medium (2.13 cm). The use of CM did not have a positive effect on blueberry growth in vitro. The results of experiment 3 indicated that explants of blueberry better developed when pH was lower (5.0) with the highest number of new shoots (2.85) and fresh weight (95.67g). However, there were no significant differences in plant height between pH used. The application of 200 mg dm–3 Actisil benefits the negative effect of higher pH of the WPM medium on micropropagation of blueberry in case of plant height, fresh weight, and biochemical parameters (proline, malondialdehyde – MDA and catalase – CAT activity).

Rhizome growth and development is regulated by phytohormone. However, endogenous phytohormones affect rhizome initiation, and sustained growth in perennial grass species remains elusive. In this study, we investigated the morphological characteristics and the content of indole-3-acetic acid (IAA), zeatin (ZT), gibberellic acid (GA3), and abscisic acid (ABA) in the rhizomes of two different Kentucky bluegrass. Using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), we performed metabolite analysis of two different rhizomes. In our study, the multi-rhizome Kentucky bluegrass material ‘Yuzhong’ had an average of 1113 rhizomes, while the few-rhizome material ‘Anding’ had an average of 347 rhizomes. The diameter of rhizome and length of rhizome internode in ‘Yuzhong’ were 1.68-fold and 1.33-fold higher than that of the ‘Anding’, respectively. The rhizome dry weight of ‘Yuzhong’ was 75.06 g, while the ‘Anding’ was 20.79 g. ‘Yuzhong’ had a higher ZT content (5.50 μg·g−1), which is 2.4-fold that of ‘Anding’ (2.27 μg·g−1). In contrast, the IAA, ABA, and GA3 content of rhizome were markedly higher in ‘Anding’ than ‘Yuzhong’. Correlation analysis revealed significant correlations between ZT and ZT/ABA with the number of rhizomes, diameter of rhizome, and length of rhizome internode, whereas IAA, ABA, GA3, and IAA/ZT were opposite. In the metabolic profiles, we identified 163 differentially expressed metabolites (DEMs) (60 upregulated and 103 downregulated) in positive ion mode and 75 DEMs (36 upregulated and 39 downregulated) in negative ion mode. Histidine metabolism and ABC transporters pathways were the most significantly enriched in the positive and negative ion mode, respectively, both of which are involved in the synthesis and transport of cytokinin. These results indicate that cytokinin is crucial for rhizome development and promotes rhizome germination and growth of Kentucky bluegrass.

Development of an efficient and eco-friendly technique to break tuber dormancy in potato (Solanum tuberosum L.) is highly demanded due to the production of two or more crops annually. Several physiological and hormonal changes have been found to be related to the breaking of tuber dormancy; however, their consistency with genotypes and different protocols have not been well clarified. This study aims to evaluate the effectiveness of four dormancy-breaking methods, that is, plant growth regulator (PGR) dipping in 30, 60, or 90 mgL-1 benzyl amino purine (BAP) and 10, 20, or 30 mgL-1 gibberellic acids (GA3) alone and in the combination of optimized concentrations; electric current application at 20, 40, 60, or 80 Vs; cold pre-treatment at 2, 4, or 6 °C; irradiation at 1, 1.5, 2, 2.5, 3, or 3.5 kGy. In addition, changes in endogenous levels of abscisic acid (ABA), zeatin (ZT), and gibberellin A1 (GA1) in six potato genotypes after subjecting to these methods were investigated. Overall, the highest effective method for dormancy duration was the PGR application which shortened the duration by 18 days, followed by electric current (13 days), cold pre-treatment (9 days), and then irradiation (7 days). The solution of 60 mgL-1 BAP significantly reduced the dormancy duration in all genotypes but did not have a significant effect on the sprout length. While 20 mgL-1 GA3 produced maximum sprout length with a non-significant effect on dormancy duration. The genotype x PGR interaction for dormancy duration was more pronounced in short- and medium-term dormancy genotypes than in long-term dormancy genotypes. The genotypes displayed a significant positive correlation between dormancy duration and ABA levels but exhibited a negative correlation between dormancy duration and ZT as well as GA1 levels. From the first to the third week of storage, ABA was decreased in tubers while, however, ZT and GA1 were increased. The obtained results could be useful for the postharvest storage of potato tuber and the related field of physiological investigation in future. [ABSTRACT FROM AUTHOR]

Alternaria brown spot is a serious disease in mandarins and mandarin hybrids. In this particular research, 9 Alterneria tolerant and 2 susceptible mutant individuals obtained from a series of in vitro and in vivo studies were used. Endogenous indole acetic acid (IAA) and zeatin hormone levels of the individuals were noted before and after the Alternaria disease inoculations in order to determine the hormonal variations during the research. It was determined that endogenous zeatin levels decreased after the inoculation compared to its initial levels. The indole acetic acid levels of the individuals increased after inoculation except for some individuals. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) are beneficial soil bacteria that colonise the rhizosphere and help plants in growth, development, and stress tolerance. While there is a significant body of research elucidating their benefits to plants, studies on the "abnormal" or "unexpected" behavior of these bacteria are almost non-existent. One such study from our laboratory has previously reported a unique situation in which a certain strain of drought and thermo-tolerant PGPR, namely, Pseudomonas putida AKMP7, becomes pathogenic towards Arabidopsis thaliana under drought conditions, but not under normal (well-watered) conditions. In this study, we have probed deeper into this phenomenon of "conditional pathogenesis". We found that, AKMP7 imparts an enhancement in plant growth under well-watered conditions, while, causing a deterioration in plant health under drought conditions. In an attempt to understand the underlying reasons for this phenomenon, we analysed the phytohormones released by Pseudomonas putida AKMP7 using LC-ESI-MS/MS technique. We identified that AKMP7 releases zeatin (a cytokinin), the auxin derivative -indole acetamide and amino acid-conjugates of auxin (indole-3-acetyl-L-alanine, indole-3-acetyl-L-phenylalanine and indole-3-acetyl-L-aspartate) in the growth medium. By treating the plants with commercially obtained forms of these phytohormones, individually or in combination with AKMP7, we identified that zeatin and auxin derivative indole acetamide can play a crucial role in the conditional pathogenesis exhibited by this bacterium on A. thaliana under drought conditions. Our work lays a foundation for further understanding the precise molecular mechanisms involved in this unique phenomenon of conditional/opportunistic pathogenesis. • The rhizobacterium Pseudomonas putida AKMP7 releases free cytokinin and auxin derivatives into the growth medium. • P. putida AKMP7 exhibits contrasting effects on A. thaliana growth under well-watered vs. dehydrating conditions. • Among all the phytohormones/derivatives analysed, tZ and IA contribute maximally towards conditional pathogenesis. [ABSTRACT FROM AUTHOR]

A highly productive and robust adventitious organogenesis protocol is key as an initial step when lemon in vitro mutagenesis or genetic transformation are addressed. Many molecules play a major role on plant regeneration, and in this study, the addition of the main naturally-occurring polyamines (spermine, spermidine, and putrescine) and their effect on endogenous cytokinins and on ethylene production have been analyzed in explants of the lemon (Citrus limon) cultivar 'Verna 51'.The three polyamines were added to the organogenesis media, and the regeneration rate and percentage were recorded. Changes produced in the endogenous cytokinins along with ethylene production were studied. Polyamines were shown to play an important role in the adventitious shoot regeneration of 'Verna 51'. However, this effect would not be related to ethylene production since changes were not detected. Comparing the three studied polyamines, it is possible to conclude that, within the studied doses, spermine (0.2 mM) and spermidine (0.3 and 0.6 mM) are more useful to induce organogenesis than putrescine in 'Verna 51'. In the most regenerative treatments, lower concentrations of cytokinins were found, which could indicate a correlation between the addition of polyamines to the culture media, the adventitious regeneration, and the metabolism of cytokinins. Key message: Polyamines are able to modulate de novo plant regeneration through changes produced in the endogenous cytokinins while do not appear to interfere directly in the ethylene production in lemon tissues. [ABSTRACT FROM AUTHOR]

Development of an efficient and eco-friendly technique to break tuber dormancy in potato (Solanum tuberosum L.) is highly demanded due to the production of two or more crops annually. Several physiological and hormonal changes have been found to be related to the breaking of tuber dormancy; however, their consistency with genotypes and different protocols have not been well clarified. This study aims to evaluate the effectiveness of four dormancy-breaking methods, that is, plant growth regulator (PGR) dipping in 30, 60, or 90 mgL−1 benzyl amino purine (BAP) and 10, 20, or 30 mgL−1 gibberellic acids (GA3) alone and in the combination of optimized concentrations; electric current application at 20, 40, 60, or 80 Vs; cold pre-treatment at 2, 4, or 6 °C; irradiation at 1, 1.5, 2, 2.5, 3, or 3.5 kGy. In addition, changes in endogenous levels of abscisic acid (ABA), zeatin (ZT), and gibberellin A1 (GA1) in six potato genotypes after subjecting to these methods were investigated. Overall, the highest effective method for dormancy duration was the PGR application which shortened the duration by 18 days, followed by electric current (13 days), cold pre-treatment (9 days), and then irradiation (7 days). The solution of 60 mgL−1 BAP significantly reduced the dormancy duration in all genotypes but did not have a significant effect on the sprout length. While 20 mgL−1 GA3 produced maximum sprout length with a non-significant effect on dormancy duration. The genotype × PGR interaction for dormancy duration was more pronounced in short- and medium-term dormancy genotypes than in long-term dormancy genotypes. The genotypes displayed a significant positive correlation between dormancy duration and ABA levels but exhibited a negative correlation between dormancy duration and ZT as well as GA1 levels. From the first to the third week of storage, ABA was decreased in tubers while, however, ZT and GA1 were increased. The obtained results could be useful for the postharvest storage of potato tuber and the related field of physiological investigation in future.

The aim of the present research work was the screening of the effect of the main cytokinin (BAP, kinetin or zeatin) in different concentrations and combinations with the auxin NAA on androgenesis of white cabbage anthers cultivated in vitro. The results obtained are regarded as an intermediary stage for the development of a reproducible protocol for in vitro regeneration of plant from anther culture. Thus, for the determination of the influence of plant growth regulators formula over the callus induction and plant regeneration from anthers cultivated in vitro in the present study the authors undergo a screening of the three most frequently utilized cytokinins (BAP, kinetin and zeatin) in different concentration and combination with the auxin NAA. The results obtained, indicated that the best morphogenetic reaction is obtained on variant with BAP as the main growth regulator.

2-Methylthio-N7-methyl-cis-zeatin (1) was isolated from the culture broth of Streptomyces sp. 80H647 along with 2 known purine derivatives, 5'-methylthioinosine (2) and AT-265 (dealanylascamycin, 3). The structure elucidation of compound 1 was accomplished by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) analyses. It inhibited the growth of Plasmodium falciparum 3D7 with a GI50 of 2.4 μm and had no effect on the growth of Arabidopsis at 2 μm. This is the first report of an N7-methylated zeatin-type natural product from Streptomyces and as an antimalarial compound. [ABSTRACT FROM AUTHOR]

Blackberry (Rubus fruticosus L.) and raspberry (Rubus idaeus L.) are well known throughout the world due to their nutritional and medicinal importance. Obtaining regenerants is an important stage for the application of cell technologies in plant growing, plant breeding, and genetic engineering. The objective of this study was to determine the best regeneration pathways for understudied blackberry and raspberry cultivars. Adventitious shoot regeneration of thornless blackberry cultivars 'Smoothstem', 'Triple Crown' and 'Karaka Black', and raspberry cultivars 'Glen Ample', 'Gusar' and 'Maria' has been studied depending on the cultivar, type explant, hormonal composition of nutritional medium, and LED lighting. To induce adventitious shoot bud formation, three types of explants: leaves, internodes, and roots obtained from in vitro plants, were cultured in a growth chamber on MS medium supplemented with different concentrations of plant growth regulators. In most cases, regeneration became visible after three weeks of cultivation. Blackberry cultivar 'Smoothstem' showed the best results and regenerated at a maximum rate of 73.3% on leaf blades and stem segments on MS supplemented with 2.0 mg L-1 TDZ. The best shoot proliferation rates of raspberries (65.5%) were observed in the 'Glen Ample' on root segments at MS medium supplemented with 0.5 mg L-1 ZEA. The blackberry and raspberry explants were exposed under LED lighting with a ratio of quanta red (R) to blue (B) light at 1:1, 1:2, 2:1, 1:4 and 4:1, monochrome red (650-670 nm) and monochrome blue (440-460 nm), and recorded regeneration. Efficient regeneration percentage (>80%) was obtained by the incubation of raspberry and blackberry explants under illumination with a ratio of red to blue spectrum: R2:B1 and R1:B1. Monochrome blue and red light inhibited shoot growth. The obtained results indicate that certain combinations of spectra LED lighting enhances plant morphogenesis. The regeneration system described here will be useful for developing a gene transfer system and can be efficient for selected raspberries and blackberries cultivars. [ABSTRACT FROM AUTHOR]

Endosperm, an ephemeral and storage tissue, serves as a source of nutrition and protection during embryo development and germination. It can be used for the cultivation of polyploid plants in vitro. Here, results of plant regeneration and acclimatization from the endosperm-derived calli of four cultivars of Actinidia arguta has been presented. Seeds excised from fresh fruit and dry seeds stored for one year served as the sources of endosperm explants of selected tetraploid cultivars of A. arguta. Callus Induction Medium (CIM; containing 0.25, 0.5, or 1 mg/l of TDZ) and Actinidia Endosperm Medium (AEM; containing 2 mg/l of 2,4-D and 5 mg/l of kinetin) were used to study the organogenic responses of the calli. On AEM, the source of explant did not significantly affect the rate of callus induction for any of the tested cultivars; no organogenic events were observed. In contrast, on CIM both the source of explants and the cultivar origin caused significant differences in callus formation and subsequent organogenic events. Histological and ultrastructural analyses revealed the adventitious nature of shoot bud formation on these media. The most efficient elongation of shoot buds was achieved after transferring organogenic calli with adventitious shoot buds to a medium supplemented with zeatin or meta-topolin. Robust root induction with minimal basal callus formation occurred on the medium with indole-3-acetic acid. Flow cytometric analysis revealed that the nuclear DNA content in the leaves of some regenerants was approximately 50 % higher (4.5 pg/2C) than that in leaves from the tetraploid seedlings (3.1 pg/2C),which confirmed that those regenerants originated from the endosperm. The regeneration of such hexaploid plants was more efficient when endosperm from fresh seeds served as an explant; therefore, fresh rather than dry seeds are recommended for endosperm-derived plant production. The hexaploid plants of A. arguta can serve as an important source of breeding material. Key message: This study reveals that the genotype, thidiazuron, zeatine, meta-topolin, and age of explants affect the induction of endosperm-derived callus and subsequent hexaploid plant regeneration from tetraploid kiwiberry. [ABSTRACT FROM AUTHOR]

Abstract Background Diospyros kaki L. is considered one of the most important economical medicinal plant in Chinese herbal medicine belonging to family Ebenaceae as it contains varied secondary metabolites and used in treatment of many diseases. For there is an efficient and promising protocol for in vitro propagation of Diospyros kaki L. cv. Costata was established Diospyros kaki L. cv. Costata although it is difficult to initiate it in sterilized artificial media due to the browning of tissue caused by oxidation of phenolics. An efficient sterilizing method for leaf and internode explants was obtained by using 0.2% mercuric chloride (Hg2Cl2) for 5 min. Woody plant medium (WPM) supplemented with 2 mg/l zeatin (Zt) + 5 mg/l isopentenyl adenine (2 iP). Calli were induced on Murashige and Skoog medium (MS) augmented with 10 mg/l Zt + 10 mg/l indole-3-acetic acid (IAA) + 500 mg/l polyvinylpyrolidone (PVP) + 0.1 mg/l thiamine HCL from internode explants. However, the regeneration efficiency was obtained with ½ MS-media fortified with 1 mg/l Zt + 2 mg/l IAA + 4 mg/l benzylaminopurine (BAp) + 0.5 g/l PVP from internode calli explants. Results The highest amounts of scopoletin 57.08, 26.42, and 25.30 (μg/g DW) were detected using reversed phase of high-performance liquid chromatography (RP-HPLC) in leaves extract of intact plant followed by regenerated and calli cultures of internod explants, respectively. Conclusion This study is the first record for in vitro propagation and production of secondary metabolites from Diospyros kaki L. using biotechnology techniques. Chemical anaysis were carried out using HPLC technique.

Known as the world’s most healthy and natural source of vegetable oil, the history of olives dates back to 10,000 years ago. The homeland of olives, a member of the Oleacea family, is Upper Mesopotamia and Southern Asia, including Southeastern Anatolia and Syria. Olives, BC It started to be cultivated on the eastern shores of the Mediterranean in the year 3000 and is one of the first fruit species cultivated in the Mediterranean region. In this respect, olive has an important place in the economy, nutrition and culture of Mediterranean countries. Currently, in most olive growing countries, olive, leafy stem or cuttings are rooted or by propagating stem shoots from seed or clonal stem. However, the so-called table olives are very difficult or completely impossible to root. The olives, which are very difficult to root, should be supported with biotechnological approaches such as micropropagation method in order to increase the product productivity. So far, many fruit species have been propagated in vitro using tissue culture methods and at the same time, some olive varieties have been successfully propagated by micro-propagation method. It made in tissue culture in the world and Turkey Olives have been compiled resources to work for the researchers in this study.

Macleania rupestris (Kunth) A.C. Smith (Ericaceae) is a plant native to the Andes, which produces edible fruits with great food and commercial potential. M. rupestris plants have been in vitro established from seeds of ripe fruits and to increase their number it is necessary to define the conditions of their multiplication. The objective of the investigation was to determine the effect of zeatin and kinetin to in vitro multiply M. rupestris plants. As a basal culture medium, Woody Plant (WP) was used. Treatments included the CIRGEBB culture medium (WP + 0.5 mg l-1 zeatin), A (WP + 0.5 mg l-1 kinetin), B (WP + 1.0 mg l-1 kinetin) and WP as control. The variables evaluated were explant height (cm), number of shoots and number of leaves, at 60 and 120 days of culture. The use of zeatin and kinetin in the WP culture medium allow in vitro multiplication of M. rupestris. However, the addition of zeatin favors the development of plants with phenotypic characteristics suitable for micropropagation. Based on the results, it is proposed to use the culture medium A (WP + 0.5 mg l-1 kinetin).

In order to investigate the possibility for in in vitro fast regeneration of Dianthus caryophyllus, different concentrations of Kinetin (Kin), 2,4-Dichlorophenoxy Acetic Acid (2,4-D) had been tested for induction of callus by leaves and stems explant using Murashige and Skoog (MS) medium. After two months in culture, response callus in the induction rate, fresh and dry weight, texture and color were evaluated. MS medium that contained 4.5 mg.L-1 2, 4-D was suitable for callus induction with leaf explants. The combination of 0.4 mg.L-1 Kin and 2.0 mg.L-1 2, 4-D also demonstrated a wonderful induction of callus on stem explants. In addition to the culture medium complemented by Kin and 2, 4-D, the influence of Zeatin at various concentrations (0.0, 0.4, 0.8 or 1.0 mg.L-1) was assessed. In MS medium that contained 0.4 mg.L-1 Kin+ 2.0 mg.L-1 2,4-D+ 1.0 mg.L-1 Zeatin, rapid callus induction and also more callus proliferation from stem explants were detected. Results indicate on callus induction that, Zeatin was more successful than Kin or 2, 4-D, but other combinations directly developed a shoot. Callus obtained from stems explant was friable, white and yellow, while callus from leaf explants was green.

In order to investigate the possibility for in in vitro fast regeneration of Dianthus caryophyllus, different concentrations of Kinetin (Kin), 2,4-Dichlorophenoxy Acetic Acid (2,4-D) had been tested for induction of callus by leaves and stems explant using Murashige and Skoog (MS) medium. After two months in culture, response callus in the induction rate, fresh and dry weight, texture and color were evaluated. MS medium that contained 4.5 mg.L-1 2, 4-D was suitable for callus induction with leaf explants. The combination of 0.4 mg.L-1 Kin and 2.0 mg.L-1 2, 4-D also demonstrated a wonderful induction of callus on stem explants. In addition to the culture medium complemented by Kin and 2, 4-D, the influence of Zeatin at various concentrations (0.0, 0.4, 0.8 or 1.0 mg.L-1) was assessed. In MS medium that contained 0.4 mg.L-1 Kin+ 2.0 mg.L-1 2,4-D+ 1.0 mg.L-1 Zeatin, rapid callus induction and also more callus proliferation from stem explants were detected. Results indicate on callus induction that, Zeatin was more successful than Kin or 2, 4-D, but other combinations directly developed a shoot. Callus obtained from stems explant was friable, white and yellow, while callus from leaf explants was green. [ABSTRACT FROM AUTHOR]

Olea europaea or the olive plant is from the family of Oleaceae and has been cultivated for its fruits that are highly nutritious, capable of reducing risks of cardiovascular diseases and to prevent cancer. The current propagation technique of olive plants in Malaysia relies on conventional methods that are less efficient in producing good quality plant stocks. Plant tissue culture offers an alternative to multiply plants from novel mother plants and is commonly applied in the propagation of various crops. This study aims to establish sterile cultures and to induce multiple shoots from Olea europaea cv.1 as a preliminary study to micropropagate olive plants for commercial farms in Malaysia. Nodal explants were surfaced sterilised with ethanol and Clorox© at different durations followed by treatments in MS media supplemented with different concentrations of Zeatin and BAP. Nodal explants surface sterilised with 70% (v/v) ethanol for 2 min and 30% (v/v) Clorox© for 8 min produced sterile explants with the survival rate of 85%. MS media supplemented 5.0 mg/L BAP was optimal for shoot induction (2.10 ± 0.31 shoots per explant) and shoot elongation (6.50 ± 1.17 mm). The current study serves as preliminary assessment for the establishment of local olive cultures. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria have been shown to enhance plant tolerance to drought stress through various mechanisms. However, there is limited research on improving drought resistance in alfalfa by genetically modifying PGPR to produce increased levels of cytokinins. Herein, we employed synthetic biology approaches to engineer two novel strains of Sinorhizobium meliloti capable of overproducing trans-Zeatin and investigated their potential in enhancing drought tolerance in alfalfa. Our results demonstrate that alfalfa plants inoculated with these engineered S. meliloti strains exhibited reduced wilting and yellowing while maintaining higher relative water content under drought conditions. The engineered S. meliloti -induced tZ activated the activity of antioxidant enzymes and the accumulation of osmolytes. Additionally, the increased endogenous tZ content in plants alleviated the impact of drought stress on the alfalfa photosynthetic rate. However, under nondrought conditions, inoculation with the engineered S. meliloti strains had no significant effect on alfalfa biomass and nodule formation.

Cytokinin is a phytohormone involved in the regulation of diverse developmental and physiological processes in plants. Its potential in biotechnology and for development of higher-yield and more resilient plants has been recognized, yet the molecular mechanisms behind its action are far from understood. In this report, the roots of barley seedlings were explored as a new source to reveal as yet unknown cytokinin-responsive proteins for crop improvement. Here we found significant differences reproducibly observed for 178 proteins, for which some of the revealed cytokinin-responsive pathways were confirmed in metabolome analysis, including alterations phenylpropanoid pathway, amino acid biosynthesis and ROS metabolism. Bioinformatics analysis indicated a significant overlap between cytokinin response and response to abiotic stress. This was confirmed by comparing proteome and metabolome profiles in response to drought, salinity or a period of temperature stress. The results illustrate complex abiotic stress response in the early development of model crop plant and confirm an extensive crosstalk between plant hormone cytokinin and response to temperature stimuli, water availability or salinity stress.

Purpose: To analyze human and bacteria proteomic profiles in bile, exposed to a tumor vs. non-tumor microenvironment, in order to identify differences between these conditions, which may contribute to a better understanding of pancreatic carcinogenesis.Patients and Methods: Using liquid chromatography and mass spectrometry, human and bacterial proteomic profiles of a total of 20 bile samples (7 from gallstone (GS) patients, and 13 from pancreatic head ductal adenocarcinoma (PDAC) patients) that were collected during surgery and taken directly from the gallbladder, were compared. g:Profiler and KEGG (Kyoto Encyclopedia of Genes and Genomes) Mapper Reconstruct Pathway were used as the main comparative platform focusing on over-represented biological pathways among human proteins and interaction pathways among bacterial proteins.Results: Three bacterial infection pathways were over-represented in the human PDAC group of proteins. IL-8 is the only human protein that coincides in the three pathways and this protein is only present in the PDAC group. Quantitative and qualitative differences in bacterial proteins suggest a dysbiotic microenvironment in the PDAC group, supported by significant participation of antibiotic biosynthesis enzymes. Prokaryotes interaction signaling pathways highlight the presence of zeatin in the GS group and surfactin in the PDAC group, the former in the metabolism of terpenoids and polyketides, and the latter in both metabolisms of terpenoids, polyketides and quorum sensing. Based on our findings, we propose a bacterial-induced carcinogenesis model for the biliary tract.Conclusion: To the best of our knowledge this is the first study with the aim of comparing human and bacterial bile proteins in a tumor vs. non-tumor microenvironment. We proposed a new carcinogenesis model for the biliary tract based on bile metaproteomic findings. Our results suggest that bacteria may be key players in biliary tract carcinogenesis, in a long-lasting dysbiotic and epithelially harmful microenvironment, in which specific bacterial species' biofilm formation is of utmost importance. Our finding should be further explored in future using in vitro and in vivo investigations.

Salicylic acid enhances the flowering process in the plant by creating new proteins under salinity stress. The study was to determine the role of salicylic acid (500 ppm) and potassium nitrate (1500 ppm), on flowering of date palm ‘Sayer’ offshoots under salinity effect. Application of salicylic acid increased the number of clusters, the number of new leaves, the content of carbohydrates, ascorbic acid, indoleacetic acid, zeatin, gibberellin, and abscisic acid significantly under salinity compared with control. Although the measured parameters were the highest in plants treated with salicylic acid, there was no distinction among potassium nitrate treatment under saltwater, and salicylic acid treatment with saltwater. Salicylic acid and potassium nitrate treatment demonstrated some amazing contrasts in protein patterns in light of gel electrophoresis. Plants treated with salicylic acid with fresh water and with saltwater showed five and six protein bands, respectively, that differed in the molecular mass of one polypeptide compared to control with freshwater. However, there was a difference in the molecular mass of two polypeptides compared to control with salt water, which showed six bands. In contrast, potassium nitrate application showed five protein bands, whether with freshwater or with saltwater. The findings could facilitate to elucidate the flowering mechanisms in date palm.

An efficient system for the in vitro propagation of the endangered medicinal and winter-hardy ornamental plant, Rhododendron mucronulatum Turcz., through high frequency shoot induction from seedlings and in vitro-derived apical shoots was developed. While testing different zeatin (Z) concentrations in the seedling culture, both axillary shoot regeneration and adventitious shoot formation on hypocotyls were observed. The highest frequency of shoot regeneration from seedlings (80 %), including formation of adventitious buds on hypocotyls (25 %), was recorded in the presence of 1.0 µM Z. The highest adventitious shoot numbers per explant (31.12 ± 6.19) were formed under 2.5 µM Z. Histological examination confirmed that adventitious buds directly originated from parenchymal cells of the hypocotyl. The effect of different concentrations of 2-isopentenyladenine and Z alone as well as in combination with indole-3-acetic acid (IAA) on axillary shoot proliferation from apical shoot explants was studied. The highest regeneration frequency (100 %) and shoot multiplication (9.70 ± 0.63) with a maximum length (15.75 mm) were obtained by using a combination of 0.1 µM IAA with 1.0 µM Z. The most efficient root formation was achieved through 4-hour pulse treatment with 148.0 µM indole-3-butyric acid followed by ex vitro rooting in a mixture of peat and sand (1 : 1). This study contributes to conventional and genetic-engineering breeding programs for creating new frost-resistant cultivars and developing a strategy for R. mucronulatum germplasm conservation, as well as commercial large-scale propagation.

Cytokinin is a phytohormone involved in the regulation of diverse developmental and physiological processes in plants. Its potential in biotechnology and for development of higher-yield and more resilient plants has been recognized, yet the molecular mechanisms behind its action are far from understood. In this report, the roots of barley seedlings were explored as a new source to reveal as yet unknown cytokinin-responsive proteins for crop improvement. Here we found significant differences reproducibly observed for 178 proteins, for which some of the revealed cytokinin-responsive pathways were confirmed in metabolome analysis, including alterations phenylpropanoid pathway, amino acid biosynthesis and ROS metabolism. Bioinformatics analysis indicated a significant overlap between cytokinin response and response to abiotic stress. This was confirmed by comparing proteome and metabolome profiles in response to drought, salinity or a period of temperature stress. The results illustrate complex abiotic stress response in the early development of model crop plant and confirm an extensive crosstalk between plant hormone cytokinin and response to temperature stimuli, water availability or salinity stress. [ABSTRACT FROM AUTHOR]

Winter wheat not only provides adequate fresh forage grass in winter, but also ensures ample grain production in summer. The mechanisms underlying the regeneration of winter wheat after mowing or grazing are not well understood. In this study, the miRNA expression profile of winter wheat was determined using RNA sequencing and the endogenous auxin and cis -zeatin concentrations, as well as the expression of related miRNA-targeted genes, were measured. During the post-mowing regeneration of winter wheat, the concentrations of endogenous indole-3-acetic acid (IAA), methyl indole-3-acetate (ME-IAA), and indole-3-carboxaldehyde (ICA) decreased, while those of cis -zeatin (cZ) increased. Moreover, 15 novel miRNAs and three known miRNAs were found to be involved in the synthesis and signalling transduction of auxins and cytokinins (CKs). Among these miRNAs, miR1153-y, miR5059-x, miR2916-x, novel-miR1532–3p, novel-miR1060–3p, and novel-miR0890–3p, were found to be negatively correlated with the expression of their target genes including auxin response GH3.7 , auxin response factor (ARF) , type-A two-component response regulator (A-ARR) , aldehyde dehydrogenase (ALDH) , and O-glucosyltransferase (CISZOG). Furthermore, miR1153-y was identified as mediating the cleavage of GH3. 7 by RACE assay. In turn, these genes inhibited the biosynthesis and signalling of IAA and activated CK signal transduction, resulting in the rapid regeneration of mowed winter wheat. This study revealed that some miRNAs exert a positive regulatory effect on the post-mowing regeneration of winter wheat by controlling the synthesis and signal transduction of IAA and CK, and our founding will aid developments in biotechnology aimed at improving the post-mowing regeneration ability of winter wheat. • Auxins and CKs plays an important role in rapid regeneration of forage winter wheat. • MiRNA affets wheat post-mowing regeneration by controlling the synthesis and signal transduction of IAA and CK. • MiR1153-y was identified as mediating the cleavage of GH3. [ABSTRACT FROM AUTHOR]

Despite summer drought may challenge plant survival in Mediterranean-type ecosystems, the role of reproductive load on drought stress and recovery has been poorly studied in invasive plants, most particularly under natural field conditions. In this study, a highly plastic clonal invasive species, Carpobrotus edulis was used to explore a putative differential response to drought between reproductive (senescent) ramets and non-reproductive ramets. Furthermore, fruit removal was used to assess how alterations on the source-sink dynamics influence plant performance during drought stress and recovery. We examined the variations in chloroplast pigments, antioxidants, lipid peroxidation and cytokinins in leaves of non-reproductive and reproductive ramets (either with intact or fruit-removed ramets) in response to summer drought stress and recovery after rains under Mediterranean field conditions. Results showed that although both ramet types within a C. edulis patch recovered at the end of the summer, increased photoprotective investment was found in leaves from reproductive ramets, thus indicating an increased photoprotective demand associated with reproduction at the ramet level. This response was associated with differentiated cytokinin contents in leaves of reproductive ramets compared to those of non-reproductive ramets. Although leaf senescence was not reversed by the fruit removal, leaves recovered their chlorophyll content after rainfall during late summer in parallel with the accumulation of cytokinins. In conclusion, C. edulis shows a huge plasticity in drought stress responses with a marked compartmentation at the ramet level, which helps at least in part to an efficient recovery from unpredictable water shortage periods in the current frame of climate change. Image 1 • Leaves from reproductive ramets showed increased photoprotection in C. edulis. • No effects were observed after fruit removal during summer drought stress. • Reproductive and non-reproductive ramets recovered at the end of the Mediterranean summer. • Ramet recovery after drought is stronger in patches with higher reproductive effort. [ABSTRACT FROM AUTHOR]