رحیم حداد

The aim of this research was to investigate the effects of different plant growth regulators and MS culture medium on the characteristics of callus weight, percentage of callus formation and embryogenesis in anther culture of two cultivars of Sina and Negin cucumbers (Cucumis sativus L.).

The experiment was conducted as a factorial in a completely randomized design with three replications. In this research, to determine the stage of growth and development of microspores, male flower buds in the sizes of 0.5 to 2.2 cm were taken from mother plants. For dyeing, the anthers were separated from the buds and placed in stocarman dye solution containing one gram of carmen powder and one hundred milliliters of 45% acetic acid for one day. Then the anthers were crushed on the laboratory slide and the microspores inside them were observed under a light microscope. In the callus induction test, the factors include two cucumber cultivars (Sina and Negin), the combination of different concentrations of BAP (0, 0.7, 0.9 and 1.1 mg/liter) and 2,4-D (0, 0.75, 1 and 1.25 mg/liter). 4 anthers were cultured in each petri dish. After placing the anthers in the culture medium, the lids of the petri dishes were closed and sealed with parafilm, and then they were covered with aluminum foil and placed in the growth chamber at a temperature of 25 ± 2 degrees Celsius in the dark for 2 weeks and the environments They were cultivated once every 2 or 3 weeks.

Cytogenetic experiments showed that 1.5 cm buds containing anthers and microspores in the mononuclear stage are suitable for anther culture. The results of the analysis of the variance of the data showed a statistically significant difference at the level of 0.01 between the interaction effects of genotype and culture medium. Anthers cultured in MS base medium and media prepared with different concentrations of BAP did not show a response and were destroyed after one month of cultivation. The average main effect of cultivars on callus fresh weight after several weeks of cultivation showed that the highest callus fresh weight was obtained in Sina variety. The comparison of the average triple interaction effects of cultivar × BAP × 2,4-D for callus fresh weight in this research has shown that Sina cultivar in MS culture medium contains the growth regulator compound 0.7 mg/liter BAP and 1 mg/liter 2,4 -D has the highest callus fresh weight. By examining the interaction effect of cultivar, auxin and cytokinin, it was found that the highest percentage of callus formation was 100% in both cultivars in environments with the combination of BAP (0.7 and 0.9 mg/liter) with 2,4-D (0.75, 1 and 1.25 mg/L) and in Sina cultivar BAP (1.1 mg/L) with 2,4-D (0.75, 1.1 and 1.25 mg/L). However, the lowest percentage of callus formation was observed in Nagin cultivar in the presence of 2,4-D hormone with a concentration of 1 mg/liter with an average of 33.333%.

In general, the use of growth regulator BAP and 2,4-D in MS culture medium induced callus in anther culture of both cucumber cultivars.

An entire open reading frame (ORF) encoding for a polypeptide of GTP cyclohydrolase I (GTPCH I) was isolated and cloned from Askari cultivar of grape (Vitis vinifera L.) berries. The 1,338-nucleotide ORF yields a 445-residue amino acid sequence with a calculated molecular mass of 48.65 kDa and a predicted isoelectric point of 6.43. The Vvgtpch I genomic sequence with a length of 4,964 bp contains two exons (169 and 1,169 bp) and an intron (2,676 bp). The gtpch I sequence of grape displayed a strong similarity with gtpch I sequence found in other plants, including peach (72%), cocoa (72%), strawberry (70%), and poplar (69%). Analysis of mRNA secondary structure revealed that the start codon of Vvgtpch I is completely exposed, suggesting a robust binding of the ribosome and efficient translation. Similar to gtpchs I from  diverse sources, molecular modeling uncovered that the monomer of VvGTPCH I adopts an αβ structure, which includes 10 α-helices and 8 β-sheets. Moreover, in silico analysis of the Vvgtpch I gene promoter identified potential cis-acting elements  responsive to environmental signals. This suggests that the Vvgtpch I gene has the capacity to be responsive to various environmental cues, such as heat, heavy metals, light, and plant hormones.

Folates are a vital necessity for the retention of normal cellular activity. In contrast to humans, other organisms including plants gain folate coenzymes via de novo synthesis. GTP cyclohydrolase I (gtpch I, EC 3.5.4.16) catalyzes the first step of the biosynthesis of tetrahydrofolate (FH4) in plants by the conversion of GTP to dihydroneopterin triphosphate and formic acid. In this research, the expression pattern of the Vvgtpch I gene was assayed in different organs of the grape by the semi-quantitative RT-PCR. The analyses demonstrated that the Vvgtpch I gene was expressed in all grape organs. The highest amounts of expression were obtained in berry and leaf, whereas the lowest amount of Vvgtpch I transcript was related to the cluster. The response of Vvgtpch I gene to abiotic stresses was also investigated under the alkali and cold stresses by the semi-quantitative RT-PCR. Under the alkali stress, the transcript level of Vvgtpch I gene decreased considerably. Similar to the alkali stress, the transcript level of Vvgtpch I gene decreased under cold stress as well. To analyze the Vvgtpch I gene expression under oxidative stress, different treatments were applied such as chemical inducers, heavy metals, and plant growth regulators to trigger the production of reactive oxygen species. The Vvgtpch I showed a strong increase and a moderate increase in the transcript amount with Cu2+ and H2O2, respectively. Whereas, its transcript level was relatively down-regulated by the heavy metals and hormonal treatments, and almost disappeared by diamide.

Human interferon gamma (hIFN-γ) as a pleiotropic cytokine, modulates both innate and adaptive immune networks and is important to the function of virtually most immune cells such as macrophages and T lymphocytes. It was originally discovered, and named, as a secretory factor that interferes with viral replication. The hIFN-γ has a multitude of roles in immune modulation and broad-spectrum pathogen defense including fungal, bacterial, and viral infections. In 1986, early clinical trials of IFN-γ initiated to evaluate its therapeutic potential. The initial studies focused on the tolerability and pharmacology of IFN-γ and systematically determined its antitumor and anti-infection activities. Nowadays, it has been approved for treatment of chronic granulomatous disease and malignant osteopetrosis, and its application as an immunotherapeutic agent against cancer and inherited and autoimmune disorders is an increasing prospect. The hIFN-γ has been heterologously expressed in different expression systems including prokaryotic, protozoan, fungal (yeasts), plant, insect and mammalian cells. However, these expression systems did not reveal satisfactory results in terms of yield, the biological activity of the recombinant protein or economic viability. Thus, it is essential to find an efficient expression system to produce glycosylated recombinant hIFN-γ with correct folding, biologically active and a high half-life in the bloodstream. The review aims to gather available information from previous studies on the production of hIFN-γ and provides direction to future researches in this field

In order to produce haploid plants through ovary culture in cucumber (Cucumis sativus L.), a factorial experiment based on randomized design was conducted with three replicates under in vitro conditions. The ovaries of Sina, a hybrid variety of cucumber were harvested one week after flowering. They were cultured in the MS medium containing different concentrations of (0, 0.8 and 1.2 mg/L) TDZ and BAP, respectively. The best calli and the highest percentage of calli were obtained in the culture medium containing 0.8 mg/L TDZ and BAP. Then, 3 week-old explants were transferred to the differentiation medium; MS medium, supplemented with NAA, IBA, IAA, 2,4-D, Pic at 0.05 mg/L and 3 cytokinins including TDZ, BAP, Kin with 0.5, 1 and 1.5 mg/L, respectively, with a total of 15 treatments and 3 replicates. They were subcultured once every two weeks. The highest percentage of callus formation was obtained in the presence of 0.05 mg/L NAA and 1.5 mg/L TDZ. The highest percentage of embryogenesis (93.33%) was observed in the presence of IAA at 0.05 mg/L and 0.5 mg/L Kin. Application of IBA at 0.05 mg/L with 0.5 mg/L Kin increased the embryogenic calli formation. Also, the highest regeneration percentage (83.33%) was found in all 4 treatments including 0.05 mg/L IBA, with 0.5 mg/L TDZ, 0.05 mg/L IBA with 0.5. 0 mg/L BAP, 0.05 mg/L 2,4-D with 1.5 mg/L BAP and 0.05 mg/L Pic, with 1.5 mg/L BAP. After transferring the explants to the second step culture media, the embryo-like structures (ELS) developed into plantlets. Finally, complete plantlets were obtained after rooting the plantlets on the MS medium with no supplement. In addition, the results of chromosome counting showed that among 10 regenerated plantlets, one plantlet was haploid, and 9 plantlets were diploid.

Melioidosis is a common disease between human and animals caused by Burkholderia pseudomallei. There is currently no effective vaccine for it. The aim of this research was to express blf1 gene in tobacco plants. By transforming the pBI121 vector into Agrobacterium tumefaciens, the blf1 gene was transferred to the tobacco plants and the primary transgenic plants were obtained. The explants obtained from the transgenic plants were used to induce hairy roots. The presence of the blf1 gene was investigated in the obtained hairy roots by PCR and Western blot analysis. The titer of antigen production was measured by ELISA technique. The insertion of the blf1 gene construct into pBI121 vector containing the ctxB gene was confirmed by PCR. The tobacco explants inoculated with A. tumefaciens were cultured on the MS medium containing benzyl-aminopurine (BAP) and 1-naphthalene acetic acid (1 -NAA). After callus formation and seedling regeneration, the seedlings with active meristems were transferred onto the hormone-free medium for rooting and transgenic tobacco plants containing the blf1 gene were produced. By preparing an explant of transgenic plants by A. rhizogenes, inoculum and hairy roots were obtained. In hairy roots, the presence of blf1 gene was confirmed using PCR and its expression was confirmed by Western blotting. By using the ELISA technique, the titer of BLF1 antigen production in the total soluble protein of hairy roots was determined to be 0.56%.

bacteria species; Burkholderia pseudomallei, Vibrio cholera, and Shigella dysenteriae are the main pathogen causing  Melioidosis, Cholera, and Shigella in humans respectively. bacterial species have a protein that has antigenic prosperities along with being a mucus based adjuvant thus easing their delivery and immunogenicity. These proteins were BLF1(B. pseudomallei), CTxB (V. cholera), and StxB (S. dysenteriae). The goal of this study was a chimeric gene composed of Blf1, CTxB, and StxB and expression of these proteins from E.coli.

Using Bioinfoamtic tools such as Protparam and Modeller the different combinations of the chimeric protein were assessed. The blf1 and stxB genes were PCR amplified from pET28a-BFL1-StxB. The 850bp fragment encompassing BFL1-StxB was cloned using SalI and NotI in the pET28a-CTxB vector. The engineered plasmid was transformed in BL21(DE3). The ctxB-stxB-blf1 gene was expressed following induction with IPTG. This induction was then assessed using SDS-PAGE.

Chimeric protein instability index gets 40.06 and the half-life of it in E. coli was over 10 hours. Codon Adaptive Index (CAI) rise to 0/9 and GC content increase to 54.9. The optimal vaccine combination for the chimeric protein was determined to be CTxB-BLF1-StxB. Expression of recombinant protein in E. coli led to the production of a chimeric protein with 48 kDa molecular weight.

The findings of the current study revealed that this antigen can be raised as a recombinant vaccine candidate which can be due to such factors as a property of the ability to stop protein synthesis in BLF1, CTxB adjuvant, and delivery of StxB protein.

In this study for the first time, different strains of Agrobacterium rhizogenes, co-cultivation times, and concentrations of acetosyringon in leaf explants of Echium khuzistanicum were examined to produce hairy roots.

The leaves of 21-day-old plant, different concentrations of acetosyringone (0,100,200 µM) and 3 strains of Agrobacterium (A4, ATCC15834 and 11325) were used for hairy root induction. In each explant, surficial wounds were created by a syringe contaminated with the bacterium and put for 10 minutes in bacterial suspension. After infection, the explants were transferred in the ½ MS solid medium supplemented with ascorbic acid (100 mg/L) to a light free growth chamber with 25 ° C temperature for 48 or 72 hours. PCR technique was used to confirm transformation by gene amplification with the rolBprimers. HPLC analysis was conducted on a high performance liquid chromatography system for shikonin measurement.  

The results of this study showed that, the first hairy roots emerged from wounded places after 14-21 days. The presence of A. rhizogenes T-DNA in the hairy root genome was confirmed by PCR using specific primers for rolB gene. Strain ATCC15834 had the highest rate of hairy root induction at 100 and 200 µM concentrations of acetosyringone indicating that the phenolic compound, acetosyringone, was effective in increasing hairy root induction. Generally, High concentrations of acetosyringone and more co-cultivation time together resulted in a significant increase in the hairy root induction in three strains of Agrobacterium rhizogenesis. Line 1 of hairy root produced 254.4±0.56 µg/g FW of shikonin.  

For the first time the results of this research showed that transformation and hairy root induction in E.khuzistanicum is possible by Agrobacterium rhizogenes and it can be used in the gene transfer and hairy root culture in order to shikonin production.

Drought stress as one of the major growth limiting factors in natural environments influences photosynthetic components and electron transfer process, elevating the production of reactive oxygen species (ROS), leading to damage to the cell. Furthermore, ROS are toxic by-products resulted from stress and are involved in signaling pathways, causing major transcriptional changes. ROS scavenging enzymes, localized in the thylakoid membrane of chloroplasts, play a key role in the detoxification of ROS. The capacity of ROS-scavenging enzymes depends on several factors including plant species, duration and intensity of drought stress, stages of plant development, and gene expression patterns of various isoforms. In this regard, novel functional and regulatory genes related to ROS-scavenging enzymes in plants are identified that play a key role in response to drought stress. These genes are differentially expressed in sensitive and tolerant species that may be related to the drought tolerance level of plant species themselves; but the overexpression of those genes in transgenic plants mainly improves drought stress tolerance. However, in some conditions, high drought stress severely damages the photosynthesis apparatus. This damage has a direct relationship to photochemical activities of both PSII and PSI that are required for protecting photosystems against photoinhibition. The photosystem protections are related to precise regulation in D1 protein accumulation under high light conditions, contributing to avoid excessive ROS accumulation. This review describes the influence of drought stress on photosynthetic characteristics, also discusses that the overexpression of genes associated with ROS scavenging enzymes in transgenic plants results in higher drought tolerance and improved photosynthetic characteristics.

The flaxseed (Linum usitatissimum L) is recognized as an important crop and the rich source of useful fatty acids, protein, dietary fiber and lignans.Lignans as antioxidant compounds are an important group of secondary metabolites that have important biological activities, such as anti-cancer effects in humans. In this study, the expression of Phenylalanine ammonia lyase (PAL) and Cinnamyl alcohol dehydrogenase (CAD) genes in the lignan biosynthesis pathway were investigated under the influence of nano-ZnO and nano-TiO2 in flax cell culture. For this purpose, a factorial experiment in a completely randomized design with three replications were done to study the effects of of nano-ZnO and nano-TiO2. Nano-ZnO at 0, 30, 60 and 120 mg/L and nano-TiO2 at 0, 50, 100 and 150 mg/L were added to cell cultures and samples were collected at 0, 24, 48, and 72 h after adding nanoparticles. The gene expression analysis were studied using Real-Time PCR. The highest expression of PAL gene was observed at the concentrations of 30 and 60 mg/L, and the lowest expression was observed at the concentration of 120 mg/L of nano-ZnO. Nano-TiO2 had no significant effect on PAL gene expression, but the use of 150 mg/L nano-TiO2 led to increased expression of CAD at 48 and 72h. CAD expression increased at 60 mg/L concentration of nano ZnO at all intervals and the lowest expression of CAD was observed at 120 mg/L nano ZnO. The results of this study showed that zinc nanoparticles are effective in increasing the expression of both PAL and CAD genes, while the nano-TiO2 only affect the expression of CAD and has no effect on the expression of PAL expression.

Mollusca are one of the most diverse animal phyla whose phylogeny is considered as a controversial subject. Although some groups were traditionally classified as mollusca, they need to be identified again. High diversity of mollusca has created considerable taxonomic problems and despite their importance in marine biota, deep phylogenetic relationships of mollusca have scarcely been investigated. The aim of this study was to determine genetic diversity and differences between mollusca species in waters of Bandar Lengeh (Persian Gulf) of Iran. A clone library of the ribosomal small subunit RNA gene (18S rDNA) in the nuclear genome was constructed by PCR, and then, after examining the clones, selected clones were sequenced. The determined clone sequences were analyzed by a similarity search of the NCBI GenBank database using BLAST. Also, the fixation index (FST) factor was used in order to measure and understand the genetic differences between studied populations. In this study, seventeen sequences were identified belonging to two classes of Bivalvia and Gastropoda and they were used for phylogenetic analysis. According to the allele frequencies at each locus, FST value was significant in samples of Bandar Lengeh meaning that migration is in the lowest rate in the studied region. The present research project exhibited that clone library of 18S rDNA might be accounted as a beneficial tool to identify marine specimens and estimate the actual species diversity in marine environments. Moreover, these findings confirmed the effective role of molecular studies for the identification and taxonomy of speciesfrom the natural resources to obtain reliable data.

Stevia rebaudiana Bert. is a medicinal plant with anti-oxidant, antimicrobial, antifungal and antiviral drug properties which contains two valuable secondary metabolites, stevioside and rebadioside A, with very high sweetness capacity. In this research hairy roots were produced from S. rebaudiana leaf disks using two strains of 15834 and A4 A. rhizogenes. Then, the best hairy root line was selected and propagated. The effect titanium dioxide nanoparticles at 20, 40 and 60 mg/l after 0, 24, 48 and 72 h of elicitation and cobalt chloride and cadmium chloride each at 100 and 200 μmol after 2 and 8 h of elicitation were studied on the production and accumulation of stevioside and rebadioside A. The results demonstrated that most treatments of elicitors at different times had significant effects on the production and accumulation of target metabolites, but titanium dioxide nanoparticles caused the highest production and accumulation of stevioside (96.88 mg/l and 24.28 mg/g DW), respectively at 40 mg/l after 24 h. However, at 60 mg/l and 48 h it had the highest effect on production and accumulation of rebadioside A after 48 h (89.39 mg/l and 21.28 mg/g DW), respectively. Also the results demonstrated that treatment of cobalt chloride and cadmium chloride both at 100 μmol after 8 h had a strong effect on the production (114.19 and 183.98 mg/l) and accumulation (29.54 and 42.87 mg/g DW ) of stevioside, respectively. Cadmium chloride at 200 μmol had the highest effect on the production and accumulation of rebadioside A after 2 h (105.51 mg/l and 25.42 mg/g DW), respectively. Meanwhile, no production of readioside A was observed at 100 and 200 μmol in 8 h treatment.

To improve Agrobacterium-mediated transformation of tobacco, factors influencing gene delivery, including genotype of the plant, bacterial strain, and Agrobacterium transformation procedure, were tested via direct somatic embryogenesis. Leaf tissue of three different tobacco genotypes (Nicotiana tabacum L. cvs. Samsun, and Xanthi, and N. benthamiana) were used as explant. Leaf explants were transformed using three Agrobacterium tumefaciens strains (EHA105, GV3101, and LBA4404) harboring the binary vector pCAMBIA1304 using three different types of transformation methods as named Agro-inoculation, Agro-infection and Agro-injection. Selection of hygromycin resistant shoots was conducted on MS medium containing 3.0 mgL-1 BAP and 0.2 mgL-1 IAA, 250 mgL-1 cefotaxime and 30 mgL-1 hygromycin. Hygromycin resistant shoots were then rooted on MS medium supplemented with 250 mgL-1 cefotaxime and 15 mgL-1 hygromycin. The results indicated that A. tumefaciens strain LBA4404 was more effective in gene delivery than EHA105 and GV3101 and Agro-infection method proved to be significantly better than two other methods. The highest transformation rate was obtained with the Agrobacterium strain LBA4404 and Agro-infection method with approximately 72.80%, 84.57%, and 93.33% for N. benthamiana, Samsun and Xanthi, respectively. Histochemical GUS assay confirmed the expression of gusA gene in putatively transformed plantlets. PCR and RT-PCR analysis using gene-specific primers confirmed the integration of the gusA and hpt genes and the expression of the gusA and hpt genes, respectively. Furthermore, Southern blot analysis confirmed stable integration of the gusA gene in selected T0 transformants.

Catharanthus roseus is a medicinal plantthat is important because of production of many alkaloids, including anticancer drugs, Vincristine and Vinblastine. Vincristine and Vinblastine are among the most important drugs for cancer treatment, but the performance of these two compounds is relatively low and the approximate amount of them in the plant is 0.0005%. Due to the high price of these compounds and small amount in this plant, efforts to increase the production of these compounds have led to extensive researches on this plant. In this experiment to study the effect of fungal extracts and time of the alkaloids production in Catharanthus roseuse cell suspension culture, test factorial randomized complete block designed with three replications. For this purpose, after preparation of cell suspensions, extracts of fungi P. indica, T. tomentosum and fungal extracts combined of P. indica and T. tomentosum at a concentration of 1% v/v was add to the cell suspension. Sampling in the time period (0, 24, 48, 72h) after the treatment were performed, and Vinblastine and Vincristine alkaloids were measured by using HPLC method. The results showed that three fungal extracts, P. indica, T. tomentosum and mixture of the fungal extract (P + T), increases the amount of Vinblastine, compared to the control and the greatest impact has been on fungal extract T. tomentosum. The average comparison of Vincristine between fungal extracts showed that the highest amount of Vincristine in the control samples and fungal extracts decrease the amount of Vincristine.

GTP cyclohydrolase I (gtpch I, EC 3.5.4.16) catalyzes the conversion of GTP to dihydroneopterin triphosphate and formic acid through a complex series of reactions. This reaction is the first committed step in the biosynthesis of FH4 (tetrahydrofolate) in plants and certain microorganisms, and BH4 (tetrahydrobiopterin) in mammals. Folates are comprised of a pABA (p-aminobenzoate) unit condensed with a pterin ring derived from GTP and a variable number of glutamate moieties. The expression analysis of a gtpch I gene was studied under abiotic and oxidative stress conditions in grape (Vitis vinifera L. cv. Askari) leaf by Semi-quantitative RT-PCR. The grape gtpch I gene was found to be differentially induced under abiotic stress conditions. The transcript level of Vvgtpch I was decrease under abiotic stress conditions such as drought, salt, and heat. Under diamide, AlCl3, ABA, and SA treatments, it was also decreased the transcripts amount of Vvgtpch I, whereas its expression was increased under H2O2, CuSO4, CdCl3, and CoCl2.

Human tissue-type plasminogen activator (tPA) is one of the most important therapeutically proteins involved in the breakdown of blood clots of brain and heart blood vessels following stroke. Therefore, several modern approaches in plant biotechnology such as nuclear and chloroplast transformation have been used to produce the valuable protein. Plant transient expression is a rapid, flexible and reproducible approach to obtain high level of expression of valuable recombinant pharmaceutical proteins. It is shown that posttranscriptional gene silencing (PTGS) process influences the expression level. Therefore, the effect of co-expression of gene silencing suppressor gene P19, derived from tomato bushy stunt virus (TBSV), has been studied on transient expression of tPA in Nicotiana tabacum cv. Xanthi. To serve this purpose, the expression proportion of injected Agrobacterium tumefaciens containing a binary vector pTRAc-tPA-ERH with Agrobacterium containing pCambia-P19 have been studied comparison with the expression level from Agrobacterium containing only the binary vector pTRAc-tPA-ERH. ELISA results from co-agroinjection experiments have shown that the expression level of tPA using p19 was 10μg/g of leaf fresh weight, which this expression level was about two times more than that from leaves injected with Agrobacterium without the vector harboring p19. Therefore, comparing to the stable transformation which needs more time to produce the protein, in transient expression, depends on the number of the injectable leaves per plant and production of 10μg of tPA per gram leaf fresh weight, a higher level of expression can be achieved less than one week. In conclusion, it seems transient expression could be utilized to express tPA usefully and the expression level could ameliorate using virus coded gene silencing suppressor to achieve the expression proportion of 10μg/g of leaf fresh weight.

Aim: The purpose of the present research project was evaluation of the effect of silicon on the severity of peroxidase genes expression and some morphological traits in both resistant and susceptible barley lines under drought stress.
Material and Total soluble protein content, photosynthetic pigments, and total RNA were extracted from the leaves affected by various treatments. Target gene was evaluated by Semi-quantitative RT-PCR analysis using synthesized cDNA. Both the peroxidase enzyme activity by Chance method and proline with Bates method were also evaluated under drought stress treatment. Accordingly, the experiment was analyzed in a factorial test based on the completely randomized design with three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 Kg soil) with three replications in a greenhouse.
Silicon application caused to increase the amount of total soluble protein and photosynthetic pigments in both lines under drought stress. Semi-quantitative RT-PCR analysis of treatments observed significant differences. Maximum of peroxidase gene expression was observed in the silicon-drought treatment. Antioxidant enzyme activities were at the highest level as shown by gene expression pattern of polyacrylamide gel analysis for treated silicon samples. A further increase was exhibited for proline accumulation caused by silicon application rather than such accumulation in stress treatment compared to control.
Silicon reduces oxidative damage induced by reactive oxygen species and with the increase in antioxidant enzyme activities caused to protect plants against environmental stresses.

The effect of sodium silicate (Si) and potassium (K) were investigated on the major antioxidant enzyme activities in two different grapevine cultivars (Vitis vinifera L., cvs Yezandai and Malinger Ramfi) under drought stress. The traits included superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), guaiacol peroxidase (GPX, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), and also physiological traits such as leaf water content ratio (LWCR), chlorophyll (Chl), soluble protein contents, hydrogen peroxide (H2O2), prolin (Pro) and glycine betaine (GB) accumulation. The experiment was performed in a completely randomized design including four treatments i.e. the control, drought, Si-drought (0.004 M sodium silicate/kg soil), and K-drought (0.004 M potassium phosphate/kg soil) with three replications in a greenhouse. Drought stress caused a considerable decrease in LWCR, chlorophyll and soluble protein contents. In contrast, compared with the plants treated with drought, applied Si and K significantly enhanced the activities of SOD, CAT, POD, GPX and APX. Under drought stress Pro and GB increased. The results indicated that Si and K partially offset the negative impacts of drought stress by increasing the tolerance of grapevine by rising antioxidant enzyme activities and osmotic adjustment.

Norfolk Island pine (Araucaria excelsa) is belonging to Araucariaceae family and is native to Norfolk Island in Australia. This plant is a woody ornamental plant of high commercial value. Since it is propagated by seed، achieving a regeneration system is one of the most important goals in this woody plant tissue culture. To evaluate the effect of cytokinins and culture media for bud induction during the process of direct organogenesis، three concentrations of different cytokinins (TDZ، Kin and 2ip) and 4 culture media (WPM، BE، ½MS and TE) were employed. Statistical analysis was conducted in a factorial experiment based on completely randomized design. The results showed that the middle shoot explants، 2ip as the best growth regulator and WPM and TE were the best media for inducing axillary buds. The overall results illustrated that plantlet production is depending on hormone type and concentration and culture medium. BAP was the only PGRs that caused root induction in micro shoots. This is the first time to report the effect of culture media in micropropagation of Araucaria excelsa.

In vitro leaf explants of GF677 hybrid rootstock and Rabi cultivar were placed on MQL medium supplemented with BAP at 0، 1، 2، 3 and 4 mg/L and NAA at 0، 0. 15 and 0. 3 mg/L concentrations. The results revealed that BAP، NAA، genotype and their interactions had significant effect on both percentage and mean number of the regenerated shoots. For GF677، the highest percentage of shoot regeneration (44 ± 1. 74) and mean number of shoots (2. 64 ± 0. 10) were obtained using 3 mg/L BAP without NAA. However، there were no significant differences among treatment combinations of BAP and NAA with regard to the Rabi cultivar. Furthermore، for GF677 and Rabi genotypes، using NAA at 1 mg/L produced the highest rooting rate (60 and 75%، respectively) and number of roots per shoot (1. 85 ± 0. 47 and 2. 4 ± 0. 46، respectively) when the shoots were maintained in the dark on the rooting medium for 10 days before transferring to a 16/8 h photoperiod. In total، 90% of the plantlets survived during acclimatization phase in the greenhouse.

Silicon is accounted as one of the elements that induces resistance to different kinds of stresses especially drought stress in plants. In this study, the effect of silicon was analyzed on the activity of antioxidant enzymes Catalase, Ascorbate peroxidase and Superoxide dismutase and also related genes expression pattern and H2O2 content on two varsities, NIMROOZ (drought resistant) and GORGAN (semi-resistant) under three treatments of drought, silicon-drought and control in a completely randomized design with three replications in four leaf developmental stage in a green house. Based on the results of factorial test, catalase activity was decreased in semi-sensitive varity and silicon treatment increased such activity in both varieties under drought stress. While the activity of two other enzymes (Ascorbat peroxidase and Superoxide dismutase) was increased under drought stress and silicon treatment intensified their activity in comparison with control. Their pattern of gene expression changed in a similar way of enzyme activity. It might be concluded that, the role of silicon in enhancing drought tolerance in barley plant is because of increasing activity of antioxidant enzymes and expression of stress responsible genes, and therefore, causes reduction in activity of reactive oxygen spices produced under drought stress.

Glucose oxidase (β-D-glucose: oxygen 1-oxidoreductase) catalyzes the oxidation of β-D-glucose to gluconic acid، by utilizing molecular oxygen as an electron acceptor with simultaneous production of hydrogen peroxide. Glucose oxidase has been purified from a range of different fungal sources، mainly from the genus Aspergillus and Penicillium and has wide applications in chemical، pharmaceutical، food، biotechnology and other industries. In this study، a glucose oxidase (GOX) -encoding gene was isolated from Penicillium funiculosum by polymerase chain reaction (PCR) technique and then was cloned into a pUC19 plasmid. Consequently، molecular structure، biochemical and phylogenetic characteristics were analyzed. Nucleotide sequence of the gene، called PfGOX، revealed 1818 bp long، encoding a protein of 605 amino acid residues. The calculated molecular mass and the predicted isoelectric point of the deduced polypeptide were 65. 79 kDa and 4. 50، respectively. Analysis of secondary and three dimensional structures of the deduced polypeptide sequence for PfGOX was shown that PfGOX is similar to those of previously reported glucose oxidase proteins from other fungi. The deduced protein sequence was indicated a high similarity to glucose oxidases isolated from fungi such as Penicillium amagasakiense، Talaromyces flavus، Talaromyces stipitatus، and Talaromyces variabilis. Phylogenetic study was also demonstrated that PfGOX gene belongs to the subgroup IA of fungous glucose oxidases

Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants and cause to damage to proteins, lipids, carbohydrates and DNA. Antioxidative enzymes such as catalase and ascorbate peroxidase are activated to protect the plants against oxidative stress. Silicon is the second most common element in soil that has beneficial effects in improving plants tolerance to drought stress. Accordingly, the effects of drought stress on semi-quantitative gene expression and enzymatic activities of both catalase and ascorbate peroxidase were investigated in two lines of two-row barley named CB-20315 (resistant) and CB- 20213 (sensitive) in tillering stage in a greenhouse. The experiment was performed in a completely randomized design with three replications for three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 kg), and analyzed in factorial experiment. RTPCR semi-quantitative analysis revealed significant differences between treatments. The highest level of gene expression was observed for both enzymes in the silicon-drought treatment. The data showed that silicone application affect antioxidant enzymes activity to increase in both studied lines under drought stress. According to the results of this study it might be concluded that silicon participate in physiological and metabolic changes to enhance plants tolerance to drought stress.

Saint Julien A (Prunus domestica spp. Insititia) is known as one of the important semi-dwarfing rootstocks with good compatibility with the majority of stone fruits (especially with plum)، which no enough research carried out of effective factors on its micropropagation. In this project the effect of 5 types medium (MS، WPM، TK، GNH and mGNH)، the interaction effects of PGRs (BAP at concentration of 0. 25، 0. 5، and 1. 0 mg/l and IBA at concentration of 0. 0، 0. 05، 0. 1، and 0. 2 mg/l])، and also the effect of carbohydrate source (Sucrose and Glucose) each at concentration of 0. 0، 10، 20 g/l were studied on mentioned rootstock shoot promotion separately. Besides، for root induction two different methods application of IBA and NAA (gradually pre-application and pulsing) was independently conducted. Results indicated that the highest healthy shootlets N0. (2. 125 per each explants) were observed on MS medium supplemented with BAP and IBA at concentrations of 0. 5 and 0. 1 mg/l، respectively، which had significant effect (α=0. 05) in comparison with other treatments. Inspite، the result implicated clearly the significant interaction effects (α=0. 01) of sucrose and glucose on both number and length of shootlet، in which the highest shootlet N0. (2. 66) with desired growth quality was obtained when MS medium supplemented with both carbohydrates each at 20 g/l concentration، but the longest shoots (8. 5 mm) were observed on MS containing 30 g/l sucrose which had significant difference (α=0. 05) in comparison with other treatments The obtained results from root induction step significantly supported the reasonable efficiency of pulsing method (with 77. 28% rooting and 1. 8 root on each shoot) to other conventional method، as well as the superiority of NAA to IBA. The rooted plantlets with 60% success were acclimated in pots containing mixture of perlite and pitmass (3:1) and were transferred into greenhouse.

Lactuca sativa is widely used as a leafy vegetable belonging to the Asteraceae family. Cotyledonary leaves of in vitro lettuce seedlings were transformed by plasmids containing the GCHI gene. Also the effects of number of days of pre-cultivation and co-cultivation of explants were examined on the transformation frequency. After co-cultivation، the explants were transferred onto the regeneration medium containing 200 mg/l ceftriaxone and 20 mg/l kanamycin. The best callogenesis was obtained in the MS medium containing 0. 05 mg/l NAA and 0. 4 mg/l BAP. Shoot regeneration was achieved after transferring the calli onto the MS medium containing 0. 05 mg/l NAA and 0. 4 mg/l BAP. Finally، the shoots were rooted on the MS medium without growth regulators. A PCR analysis of the genomic DNA confirmed the presence of GCHI genes in both T0 and T1 plants. PCR analysis of T0 plants revealed that 10 out of 52 plants were positive for the GCHI gene. The transformation frequency was 19%.