Callus Growth Rate Research Articles

The effects of chitosan and salicylic acid on elicitation of secondary metabolites and antioxidant activity of safflower under in vitro salinity stress

This study investigated the effects of different concentrations of two elicitors, namely chitosan (CHT) (25 and 50 mg L−1) and salicylic acid (SA) (50 and 100 mg L−1) on the production of secondary metabolites (SMs) and antioxidant activity of safflower callus under salinity stress. The content of total phenolics, total flavonoids, total flavonols, anthocyanin and antioxidant activity with 1,1-diphenyl-2 picrylhydrazyl assay (DPPH), significantly increased under salinity stress including 1.5% (w/v) sodium chloride. Under salinity stress, the highest content of total phenolics and total flavonoids were observed under elicitation by 50 (mg L−1) of SA and 25 (mg L−1) of CHT, but the highest callus growth rate (0.048 mm day−1), highest content of total flavonols (4.2 mg RE g−1 FW) and the highest DPPH activity (61.48% of inhibition) were observed under elicitation by 50 (mg L−1) of SA under salinity stress. This indicated partial superiority elicitation of SA over CHT for callus growth and SMs production of safflower under salinity stress. This new elicitation opens new avenues for the selection and exploitation of the best elicitors and their dosages for the enhancement of commercially important SMs in safflower as an important medicinal plant at cellular level. Effects of chitosan and salicylic acid on elicitation of SMs of safflower under in vitro salinity stress.

Modulation of callus growth and secondary metabolites in different Thymus species and Zataria multiflora micropropagated under ZnO nanoparticles stress.

Thymus species are aromatic plants with diverse applications in food industries and medicine. This study was conducted to evaluate the potential effect of ZnO nanoparticles (NPs) on callus proliferation and thymol and carvacrol production in three Thymus species, that is, T. vulgaris, T. daenensis, and T. kotschyanus, and Zataria multiflora. For this purpose, callus induction was performed on Murashige and Skoog (MS) medium containing different plant growth regulators (PGRs). After optimization of callus growth, the effects of different concentrations of ZnO NPs (100 and 150mgL-1 ) were investigated. MS containing 2mgL-1 of 2, 4-dichlorophenoxy acetic acid (2,4-D) and 1mgL-1 of kinetin (Kin) revealed significantly highest fresh weight (0.18g) of callus in T. kotschyanus. Callus growth rate (0.079mmday-1 ) was found highest in T. vulgaris under similar conditions. Moreover, highest callus induction (92.50%) was achieved by T. kotschyanus in MS containing 2.5mgL-1 of 2,4-D. Regarding the highest content of thymol (22.8mgL-1 ) and carvacrol (0.68mgL-1 ) evaluated by high-performance liquid chromatography, best results were achieved under 150mgL-1 of ZnO NPs in T. kotschyanus and T. daenesis, respectively. This is simple and cost-effective method to be applied on industrial level for production of enhanced secondary metabolites content.

Elicitation of Stevia Glycosides Using Salicylic Acid and Silver Nanoparticles Under Callus Culture

Development of biosynthesis of phytochemicals, especially medicinal products, is highly important due to their broad bioactivity properties. In this study, optimization of callus growth was initially carried out using various combinations of plant growth regulators. Callus with the highest fresh weight was produced on Murashige and Skoog (MS) medium containing 1 (mg/l) naphthalene acetic acid + 0.5 (mg/l) benzyl aminopurine. The effect of different concentrations of salicylic acid (SA) (0.25, 0.5 and 0.75 mg/l) and silver nanoparticles (Ag NPs) (15, 30, 45 and 60 mg/l) on callus growth as well as the possibility of stevia glycosides (SGs) production in callus culture was subsequently evaluated. The SA elicitation, at a concentration of 0.75 (mg/l), resulted in the highest level of callus growth rate (0.1 cm/day), callus diameter (0.79 cm) and relative callus fresh weight (0.085). Likewise, 45 (mg/l) of Ag NPs led to the highest amount of stevioside (32.34 mg/g dry weight callus). The addition of 0.25 (mg/l) of SA to the MS medium led to production of the highest amount of rebaudioside A (3.40 mg/g dry weight callus). The results of this study may enhance the commercial application of important glycosides prevalent in Stevia by highlighting that the nano-elicitors and SA should be utilized at optimized concentrations.

In vitro micropropagation and allelopathic effect of lantana (Lantana camara L.)

The invasive plant, lantana (Lantana camara L.), is well known as a traditional medicinal plant and it may become important in the development of modern drugs. Lantana has long been touted as containing potent allelochemicals and in vitro-produced tissues may be appropriate sources for the production and isolation of bioactive compounds. In this research, effective techniques for shoot multiplication and root and callus induction were developed and the allelopathic efficiency of in vitro leaf and callus was examined. The optimized medium for shoot multiplication was Murashige and Skoog (MS) medium supplemented with 12.0–20.0 μM thidiazuron. For rooting, high root numbers were obtained on MS medium containing 5.0 or 10.0 μM 1-naphthalene acetic acid (NAA). In addition, the highest relative growth rate of callus was achieved when lantana leaf was cultured on NB medium (MS medium with 21.5 μM NAA and 22.5 μM N6-benzyladenine). For allelopathic effects, the results suggested high potential activity of lantana leaf and callus that was able to variably inhibit the seed germination and seedling growth of all four test species. Leaf and callus extract had no significant effect on the germination of Brassica campestris var. chinensis. Callus extract showed superior ability to suppress germination for Ipomoea aquatica Forsk. and Zea mays L. but inferior inhibition ability for Sorghum bicolor L. These results suggested that the extract of lantana in vitro leaf and callus will be an interesting natural source for further study to develop natural herbicides.

Effects of heterologous expression of Populus euphratica brassinosteroids biosynthetic enzyme genes CPD (PeCPD) and DWF4 (PeDWF4) on tissue dedifferentiation and growth of Arabidopsis thaliana seedlings

To understand the functions of Populus euphratica CPD (PeCPD) and DWF4 (PeDWF4), the responses to exogenous phytohormone in Arabidopsis-PeCPD and -PeDWF4 transgenic lines (PeCPD-TL and PeDWF4-TL) and corresponding wild type (WT) seedlings were investigated. Results showed that all of PeCPD-TL, PeDWF4-TL and WT seedlings cultured on the mediums containing 2,4-dichlorophenoxyacetic acid (2,4-D) + 6-benzylaminopurin (6-BA) or 2,4-D + 6-BA + brassinolide (BL) could be dedifferentiated to callus with 100% frequency, but they displayed strong differences in callus formation sites, callus growth rates (CGRs) and tissue dedifferentiation degrees. On the medium containing 2,4-D alone, the seedlings of all the plants could formed callus, but callus formation times (CFTs) were delayed, and callus formation rates (CFRs) were differentially decreased. After adding lower concentrations of BL, their CFRs were all restored to 100%, but tissue dedifferentiation degrees were obviously lower than these on the mediums with 2,4-D + 6-BA or 2,4-D + 6-BA + BL. On the mediums containing 6-BA or 6-BA + BL, the seedlings of all the plants failed to produce callus. Semi-quantitative RT-PCR analysis also showed that the transcription levels of PeCPD, PeDWF4, AtCPD and AtDWF4 in PeCPD-TL, PeDWF4-TL and WT were evidently different. These results suggest that PeCPD and PeDWF4 play similar but not exactly the same roles in the regulation of callus morphogenesis of Arabidopsis seedlings, and that BL can partially replace the role of cytokinin to induce callus formation through interacting with auxin.

Induced dedifferentiation of barley (Hordeum vulgare L.) embryonic cells and its relationship with agronomic traits.

This study was carried out to investigate the response of 42 Iranian and European barley (Hordeum vulgare L.) cultivars to induced dedifferentiation of embryonic cells via immature embryo culture and understand the relationship between embryo culture characters and agronomic traits. The cultivars were evaluated for dedifferentiation of embryonic cells or callus induction from immature embryo culture based on a completely randomized design with unequal replication. Immature embryos were placed scutellum down on cell dedifferentiation medium based on MS and supplemented with 2.5 mg/l 2,4-D. The developed calli were transferred to MS regeneration medium with different concentrations and combinations of plant growth regulators. The results of group comparisons showed that Iranian cultivars were greater than European cultivars regarding callus growth rate, callus primary diameter and total regenerated plantlets. The path correlation analysis revealed that grain width and kernel filling period had the highest positive and negative direct effects on embryo culture traits, respectively. Clustering cultivars based on the embryo culture characters and agronomic traits divided the cultivars into three groups. The third group consisted of the cultivars which all of them were with the highest mean for flag leaf length, days to anthesis, grain yield, callus growth rate and callus primary diameter. Mantel test revealed a negative (-0.101) and significant correlation (P<0.01) between embryo culture characters and agronomic traits. The significant relationships between few numbers of embryo culture characters and agronomic traits confirm that these characteristics could be genetically dependent and also tissue culture characters can be estimated from agronomic data.

PEG Induces High Expression of the Cell Cycle Checkpoint Gene WEE1 in Embryogenic Callus of Medicago truncatula: Potential Link between Cell Cycle Checkpoint Regulation and Osmotic Stress.

Polyethylene glycol (PEG) can be used to mimic osmotic stress in plant tissue cultures to study mechanisms of tolerance. The aim of this experiment was to investigate the effects of PEG (M.W. 6000) on embryogenic callus of Medicago truncatula. Leaf explants were cultured on MS medium with 2 mg L-1 NAA and 0.5 mg L-1 BAP for 5 months. Then, calli were transferred to the same medium further supplemented with 10% (w/v) 6000 PEG for 6 months in order to study physiological and putative molecular markers of water stress. There were no significant differences in growth rate of callus or mitotic index ± PEG although embryogenic potential of PEG treated callus was morphologically enhanced. Cells were rounder on PEG medium and cell size, nuclear size and endoreduplication increased in response to the PEG treatment. Significant increases in soluble sugar and proline accumulation occurred under PEG treatment compared with the control. Significantly, high MtWEE1 and MtCCS52 expression resulted from 6 months of PEG treatment with no significant differences in MtSERK1 or MtP5CS expression but down regulation of MtSOS expression. The results are consistent in showing elevated expression of a cell cycle checkpoint gene, WEE1. It is likely that the cell cycle checkpoint surveillance machinery, that would include WEE1 expression, is ameliorating the effects of the stress imposed by PEG.

Experimental Paper. In vitro synthesis of mucilage in Plantago ovata Forsk affected by genotypes and culture media

SummaryIntroduction: Psyllium (Plantago ovata Forsk) is medicinally used mainly for its mucilage content. Objective: In the present study, an attempt was made to improve mucilage yield under in vitro callus culture using different genotypes, explants and culture media. Methods: The effects of a range of concentrations of plant growth regulators including 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (Kin) were evaluated on mucilage synthesis under in vitro culture using cotyledon, hypocotyl and seed explants. Fourteen genotypes originating from different geographical regions of Iran were used to evaluate their response to in vitro mucilage synthesis. Results: The highest rate of callus induction (76%) and callus growth rate CGR (0.38 mm/day) were induced on MS medium supplemented with 0.5 mg/l 2,4-D and 1 mg/l Kin and the hypocotyl explant. The results of analysis of variance showed significant genotypic differences for callus induction, CGR and mucilage content of callus and seeds. The mucilage content ranged from 0.38 to 0.08 (g/g DW) and 0.13 to 0.042 (g/g DW) for callus and seed, respectively. The superior callus induction (73%), CGR (0.45 mm/day) and mucilage content of callus (0.38 g/g DW) was denoted to Po1 genotype. The callus produced nearly three times more mucilage than the seeds using superior genotype (Po1). Conclusion: The results of this study revealed that high efficiency of callus culture of P. ovata using hypocotyl explant accompanied by the exploration of genetic diversity are important to improve the yield of mucilage synthesis by in vitro callus culture.

In vitro Salt Tolerance of Safflower (Carthamus tinctorius L.) Genotypes using Different Explants

To evaluate the response of different genotypes of safflower (Carthamus tinctorius L.) to in vitro salt stress was conducted. Callus derived from leaflet, pedicel, hypocotyls, and adaxial and abaxial surfaces of the leaf were subjected to in vitro salt stress at 0, 100 and 200 mM of NaCl. The relative growth rate (RGR), callus growth rate (CGR), relative water content (RWC), tolerance index (TOL) and necrosis percentage were assessed. Results of analysis of variance indicated significant effects of salt stress, significant differences among genotypes for all traits and significant genotype × salt stress interaction for CGR, RWC and necrosis traits. The application of NaCl decreased RGR, CGR, RWC and TOL, significantly, while a significant increase observed across all the tested explants and genotypes for necrosis percentage data. An Iranian safflower genotype (K21) superior for RGR, RWC and TOL was the most salt tolerant genotype at the cellular level.Plant Tissue Cult. & Biotech. 26(2): 231-242, 2016 (December)

In vitro application of integrated selection index for screening drought tolerant genotypes in common wheat

This experiment was conducted on 20 wheat genotypes during 2010-2011 growing season at the Razi University, Kermanshah, Iran. A completely randomized design with six replications was used for callus induction and a 20 × 2 factorial experiment with three replications was used for response of genotypes to in vitro drought stress. ANOVA exhibited highly significant differences among the genotypes for callus growth rate, relative fresh mass growth, relative growth rate, callus water content, percent of callus chlorosis and proline content under stress condition (15 % PEG). PCA showed that the integrated selection index was correlated with callus growth index, relative fresh mass growth, relative growth rate and proline content indicating that these screening techniques can be useful for selecting drought tolerant genotypes. Screening drought tolerant genotypes and in vitro indicators of drought tolerance using mean rank, standard deviation of ranks and biplot analysis, discriminated genotypes 2, 18 and 10 as the most drought tolerant. Therefore they are recommended to be used as parents for genetic analysis, gene mapping and improvement of drought tolerance.

Genetic Selection for Salt Tolerance in Some Egyptian Wheat Genotypes (Triticum aestivum L.) via Tissue Culture

Five wheat genotypes and their hybrids under four salinity (sea water) levels were considered for tissue culture and randomly amplified polymorphic DNA (RAPD). The genotypes and the hybrids differed in their ability to callus induction, callus fresh weight and regeneration. Among the genotypes, Sakha 93 (P1) followed by Line WB19 (P5) was the most tolerant genotypes for salinity and gave the highest growth rate (46.6%) and (46.3%), respectively while Giza 168 (P3) was the most sensitive one to salinity with lowest growth rate (26.6%). All hybrids scored higher averages in callus growth rate than their parents. P1 × P5 followed by P1 × P2 and P1 × P4 produced the highest growth rate 75.6, 59.1 and 52.6% over hybrids while P3 × P4 had the lowest rate 28.5%, respectively. The hybrid P1 × P5 gave the highest percentage of plant regeneration over all genotypes and their hybrids followed P2 × P5, P1 × P2 and P4 × P5. The highest number of RAPD specific markers scored for hybrid P1 × P5 was (6 markers), while Line WB19 (P5), P1 × P2 and P2 × P5 were (4 markers). These markers can be verified as the RAPD markers associated with salt tolerance.Plant Tissue Cult. & Biotech. 26(1): 25-36, 2016 (June)

Modelling the growth kinetics of callus cultures from the seedling of Jatropha curcas L. according to the modified Gompertz model

One of the most important preliminary investigation of callus attributes is the growth characteristics. Most often than not, callus growth curve is sigmoidal in characteristics. In this work, we model callus growth from the seedling of Jatropha curcas L. according to the modified Gompertz model from published literature to acquire essential growth constants. These growth constants can be obtained with better precision using model such as the modified Gompertz. Parameters obtained from the fitting exercise were maximum callus growth rate (m), lag time () and maximal callus production (Ymax) of 0.193 d-1, 2.91 days and 0.38 g callus/25 mL culture, respectively. Growth parameter constants extracted from the modelling exercise will be helpful for additional secondary modelling implicating the consequence of media conditions as well as other factors on the growth of callus from this plant.

Intraspecific variations in shell calcification across thermal window and within constant temperatures: Experimental study on an intertidal gastropod Monetaria annulus

The relationship between temperature and shell growth was examined by rearing an intertidal cowrie species, Monetaria annulus (Gastropoda, Cypraeidae), at seven constant temperatures between 21°C and 34°C over four experimental years. Data on shell growth were collected during the callus-building stage, in which calcification exclusively occurs around the spiral shell constructed in the juvenile stage. Our experiments elucidated some clear trends among temperatures, although careful consideration is required to interpret the results obtained under the potential confounding factors between temperature and experimental year. Calcification was accelerated by increasing temperature in the range between 21°C and 33°C, and drastically slowed down at 34°C probably due to heat stress. No relationship was found between body size and callus growth rates. The duration of callus-building indicated a negative exponential relationship with rearing temperature. However, no simple relationship was found between temperature and final shell thickness; the final shell thickness described two peaks around 21°C and 30°C. This finding strongly suggests that a physiological control by calcifiers cannot be ignored to explain the thermal response of calcification rates. Our results also suggest that considering the thermal seasonality as well as the difference in mean temperature, is required to explain the negative latitudinal clines in shell thickness frequently observed in molluscan species. We also focused on the variation among the individuals reared at the same temperatures. Statistical analyses suggested that the final shell thickness and the duration of calcification were better described by the normal and lognormal distributions, respectively. The distribution of shell growth rates did not considerably deviate from the normal distribution with respect to skewness and kurtosis. However, their heteroscedasticity among temperatures was inherent and significant; its variance positively depended not on the mean but on temperature. The observed pattern might be an evidence that possible stabilization selection on calcification rates is more relaxed at warmer temperatures.

In vitro study on salinity screening in rice

SUMMARY Two moderately resistant rice cultivars, White ponni and BPT – 52904 were used to selection of promising saline tolerant callus lines through screen for salinity tolerance under in vitro condition. Embryogenic calli was obtained when tissue culture basal media supplemented with 2 mg L -1 2,4-D along with 0.5 mg L -1 kinetin and 1 mg L -1 NAA. A significant reduction in callus growth rate (Relative growth rate) and callus induction per cent was noticed in media supplemented with different concentration of saline treatment, from 0.5 to 1.0 and 1.5 per cent NaCl. But the time elapsed for callus induction was increased with higher concentration of salt in the medium. A significant number embrogenic calli was survived in lower concentration, 0.5 and 1.0 per cent of NaCl showed good regeneration capacity in regeneration media. Few promising saline tolerant plants were recovered and transferred to the rooting media before adapting to acclimatization. Hence, this in vitro technique with different NaCl stress could have been used effectively to screening for salt screening in rice, rather than the field screening.

Effects of Osmolytic Agents on Somatic Embryogenesis of Saffron (<i>Crocus sativus </i>L.)

A protocol for callus induction from meristem tissues and subsequent somatic embryo formation were established in this study. Explants were taken from apical and lateral meristems of saffron and these explants were cultured on MS medium supplemented with combinations of 2.4-dichlorophenoxyacetic acid (2.4-D) and Kinetin (Kn). The effects of osmotic agents such as abscisic acid (ABA), polyethylene glycol (PEG) and Gelrite on somatic embryogenesis were also investigated. After 45 and 60 days of culture, calli were induced from apical and lateral meristems, respectively. The apical meristems yielded higher quality calli when compared to the lateral meristems. The highest frequency of callogenesis and the growth rate of callus were achieved from apical meristems on Murashige and Skoogs (MS) medium supplemented with 2.4-D (2 mg/l) and Kinetin (0.5 mg/l). After 45 days of subculture, the segments of nodular calli were transferred to plant growth regulator (PGR)- free media for induction of pre-embryogenesis embryo formation. Pre-matured embryos were cultured on MS medium supplemented with different osmotic agents such as Gelrite, ABA and PEG to study their effects on embryo maturation. Both PEG and ABA proved more effective for somatic embryo maturation as compared to Gelrite.

Callus induction in plantain (Plantago major L.) for in vitro production of mucilage

Plantago major is a medicinal herb belongs to the family Plantaginaceae. The effects of a range of plant growth regulators and different explants on mucilage production were examined. Root and leaf tissues were used as explants. Murashinge and Skoog (MS) medium supplemented with 2,4-D or Kinetin, at 0.01, 0.1 and 0.5 mg l -1 alone or in combination with IAA 1 mgl-1 for callus induction. Result of analysis of variance showed significant difference between explants for some traits included callus induction rate, fresh weight, and callus diameter. Also, significant differences were observed between media for callus induction, callus diameter, fresh weight, dry weight, relative water content of callus, mucilage harvest index and mucilage yield. The best response was observed from root segments on MS medium containing 0.8 mg/l 2,4,D and 0.1mg l -1 kinetin in some traits included callus diameter, fresh and dry weight, mucilage percentage and mucilage yield. Results revealed that the highest relative growth rate of callus was observed on media containing 1 mg l-1 2,4-D and 0.5 mg l-1 kinetin. MS medium supplemented with 2.5 mgl -1 2,4-D and 0.01 mg l -1 kinetin showed the highest harvest index of mucilage. Optimal medium for mucilage production was found to be MS medium containing 0.8 mgl -1 2,4-D and 1 mg l-1 kinetin and root as explants. Results of mean comparison for mucilage production showed that media containing 0.8 mg l -1 2,4-D and 0.1 mg l -1 kinetin and leaf as explant was produced higher mucilage than that of control plant.

Callus-mediated and direct protocorm-like body formation of Bletilla striata and assessment of clonal fidelity using ISSR markers

Two efficient morphogenetic pathways for micropropagation of Bletilla striata (Thunb.) Reichb. f. have been established through the callus-mediated and direct formation of protocorm-like bodies (PLBs) from protocorms and shoot tips. Green calli were induced from the basal surface of protocorms and the cut-end of shoot tips on Vacin and Went (VW) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) or α-naphthalene acetic acid (NAA) after 3–5 weeks, with the highest frequency of explants forming callus (48.0 %) from protocorms at 1.0 mg l−1 2,4-D. The calli obtained from all plant growth regulator (PGR) treatments could proliferate and differentiate PLBs on the PGR-free medium. NAA and 2,4-D significantly enhanced the growth of callus. The fastest growth rate of callus was achieved at the combination of 1.0 mg l−1 2,4-D and 1.0 mg l−1 TDZ with 46.2-fold within 3 months. The regeneration of PLBs from callus was significantly improved by 6-benzyladenine (BA), and a mean number of 48.4 PLBs was produced from 100 mg calli at 1.0 mg l−1 BA within 3 months. BA and thidiazuron (TDZ) promoted the direct formation of PLBs from explants. The highest frequency of direct PLBs formation (76.0 %) and the highest mean number of PLBs per explant (30.2) were observed in protocorms cultured with 0.5 mg l−1 BA. Assessment of clonal fidelity by inter-simple sequence repeat (ISSR) markers revealed similarity ranges of 99.8–100.0 % between the regenerants and their mother plants and 99.5–100.0 % among the regenerants, which suggested the micropropagation protocols were genetically stable.

Assessment of immature embryo culture to select for drought tolerance in bread wheat

In order to evaluate the response of bread wheat genotypes to callus induction and in vitro drought stress, an investigation was carried out as a factorial experiment with a completely randomized design and five replications. The results of analysis of variance indicated significant differences between the entries and stress levels for callus relative growth (CRG), callus relative growth rate (CRGR), callus growth rate (CGR), percentage of callus chlorosis (PCCH) and percentage of callus water content (PCWC) indicating the presence of genetic variability, different responses of genotypes to different drought intensities and invitro selection of droughttolerant genotypes. Mean comparisons between genotypes revealed that maximum CRG, CGR, CRGR, PCWG, PCCH and INTOL were attributed to genotypes 5, 16, 17, 2, 3 and 20 (drought tolerant), respectively. Graphic observation exhibited that indices of drought tolerance decreased with increase of PEG concentrations. Cluster analysis of genotypes (Ward’s method) based on CRG, CGR, CRGR, PCWG, PCCH and INTOL and subsequent discriminant analysis for confirming the number of clusters, grouped the genotypes into four different clusters. The first group included genotypes 1, 3, 6, 7, 12, 13 and 18, the second group included genotypes 2, 4, 8, 9, 10 and 11 and the third group consisted of genotypes 14, 16, 17, 19 and 20, while the genotype 15 formed the fourth group. Superior genotypes 2, 5 and 16 showed drought tolerance at the callus culture level together with their high potential for callus induction leaded us to the conclusion that a hybridization breeding program using these superior plant materials supplemented with in vitro selection for drought tolerance might be beneficial for improvement drought tolerance in bread wheat.

Cytokinin, auxin, and abscisic acid affects sucrose metabolism conduce to de novo shoot organogenesis in rice (Oryza sativa L.) callus.

BackgroundShoot regeneration frequency in rice callus is still low and highly diverse among rice cultivars. This study aimed to investigate the association of plant hormone signaling and sucrose uptake and metabolism in rice during callus induction and early shoot organogenesis. The immatured seeds of two rice cultivars, Ai-Nan-Tsao 39 (ANT39) and Tainan 11 (TN11) are used in this study.ResultsCallus formation is earlier, callus fresh weight is higher, but water content is significant lower in ANT39 than in TN11 while their explants are inoculated on callus induction medium (CIM). Besides, the regeneration frequency is prominently higher in ANT39 (~80%) compared to TN11 callus (0%). Levels of glucose, sucrose, and starch are all significant higher in ANT39 than in TN11 either at callus induction or early shoot organogenesis stage. Moreover, high expression levels of Cell wall-bound invertase 1, Sucrose transporter 1 (OsSUT1) and OsSUT2 are detected in ANT39 at the fourth-day in CIM but it cannot be detected in TN11 until the tenth-day. It suggested that ANT39 has higher callus growth rate and shoot regeneration ability may cause from higher activity of sucrose uptake and metabolism. As well, the expression levels of ORYZA SATIVA RESPONSE REGULATOR 1 (ORR1), PIN-formed 1 and Late embryogenesis-abundant 1, representing endogenous cytokinin, auxin and ABA signals, respectively, were also up-regulated in highly regenerable callus, ANT39, but only ORR1 was greatly enhanced in TN11 at the tenth-day in CIM.ConclusionThus, phytohormone signals may affect sucrose metabolism to trigger callus initiation and further de novo shoot regeneration in rice culture.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-5) contains supplementary material, which is available to authorized users.

청목노상(Morus alba cv. Cheongmoknosang) callus의 배양조건에 따른 Helicobacter pylori 억제물질의 생산

The optimal condition for Morus alba cv was an MS culture medium at for 20 days. Cheongmoknosang callus showed inhibitory activity against Helicobacter pylori at 1.05 g of wet weight of the cultured callus. The callus formation of Morus alba cv. Cheongmoknosang was influenced by naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D), 6-benzylaminopurine (BA) and kinetin at concentrations of 2 mg/l. The growth rate of callus was higher than it was when these hormones were mixed with a single hormone. Thus, the optimal condition for direct callogenesis was to incubate with mixture (2,4-D/NAA) of 2 mg/l concentration at for 20 days. Moreover, the optimal culture condition of the biomass in the mass production of inhibitory compounds against Helicobacter pylori from Morus alba cv. Cheongmoknosang callus was to incubate in an MS broth (each concentration 1 mg/l of 2,4-D and BA). When Morus alba cv. Cheongmoknosang callus were incubated for 20 days in a bioreactor, Helicobacter pylori inhibition of callus extracts was the highest at a clear zone of 16 mm.