جستجوی مقالات مرتبط با کلیدواژه « root » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

 Thymus fallax from the Thymus genus belongs to the Lamiaceae family. It contains high amounts of thymol and carvacrol. Due to its antiseptic, antibacterial, and antioxidant properties, it has many uses in the pharmaceutical and health industries. The species is mainly distributed in the west, northwest, and Alborz Mountains in northern Iran. For domestication of the Thyme species, utilizing micronutrients such as selenium as a complimentary nutrient may affect the yield increment of the species. Selenium is a rare and non-metal element that has been recently highly noticed due to its antioxidant, antiviral, and anti-cancer properties on humans and increasing the tolerance of plant species to abiotic stresses. Some scientific communities suggest that this element be used as a plant fertilizer. In thyme species, the number and size of stomata and trichomes significantly affect the quality and quantity of essential oils. Therefore, this study aimed to investigate the effects of selenium concentrations in two forms of nanoparticles and bulk (selenite sodium) on morphological and micromorphological characteristics of Th. fallax.

 The possible effects of three concentrations (2, 4, and 8 ppm) of selenium in bulk (selenite sodium) and nanoparticle forms along with control were studied on morphologic and micro-morphologic characteristics of Th. fallax using a completely randomized design with three replications. Seeds of the species were collected from Saheb region,  located in Saghez County in Kurdistan province in the western part of Iran, at 1750 m.a.s altitude. The seeds were sown in jiffy pots containing a combination of peat moss and perlite under greenhouse conditions. Then, the seedlings were transplanted in plastic pots until the plantlets were grown to the 4-leaf stage. The plants were sprayed with the treatments six times at two-week intervals. Plants were also irrigated twice a week using Hoagland solution as a required micro and macronutrient source. Three days after the last treatment application, several morphological and micro-morphological traits were recorded on the individual plants. The data was statistically analyzed. The means of treatment were compared using the Duncan multiple range test.

Results showed significant effects of treatments on many studied traits. Stem length was increased by spraying 4ppm selenium concentrations in bulk and nanoparticle forms by 31% and 16%, respectively. In contrast, the same trait showed a 22% decrease when using eight ppm in the form of nanoparticles. The highest number of stems was obtained at a low concentration of nanoparticles, which had 37% increments compared to the control. The high concentrations of bulk and nanoparticle treatments decreased the stem number by 37% and 12%, respectively. Effects of the treatments on micro-morphological characteristics, such as the number of trichomes on both upper and lower leaf surfaces, were significant. The 8ppm nanoparticles treatment caused the most trichomes on both the upper (61.7) and lower (33.2) leaf sides, which was 158 and 296% higher than the control. 

Lower concentrations of selenium increased the majority of the morphological traits. In contrast, higher concentrations of selenium decreased plant growth and development. Except for the number of trichomes on the upper and lower sides of the leaves, micro-morphological traits were not affected by higher levels of selenium concentrations. It seems that utilizing low concentrations of selenium could be beneficial as a complementary nutrient for the cultivation of Thyme species.

Cold is one of the important stresses in cold and temperate regions and improving cold tolerance is in the top priority of the lentil breeding programs. NAC transcription factors play an important role in response to various biological stresses, including cold stress. In this study, to evaluate the expression of MfNAC, MtNAC57 and GmNAC2 genes, the plants of Gachsaran lentil cultivar were subjected to five temprature treatments in a completely randomized design with three replications. Twenty-nine old plants were subjected to duration of cold stress treatments including 6h, 12h, 24h and 48h at 2°-4°c and plants grown under greenhouse conditions (23°C) were considered as controls. Total RNA extraction from tissues was performed using lithium chloride method and cDNA was synthesized using TaKara kit. For each treatment, real-time PCR was performed in both shoot and root in three biological and two technical replications. Actin gene was used as internal control. The results of analysis of variance of all studied genes showed that there was a significant difference between the different duration of cold treatments in both shoot and root. GmNAC2 gene expression decreased significantly in the shoot, 6 hours after stress, while in the root, the expression decreased 24 hours after stress. The expression of MtNAC57 gene in 6h, 12h, and 24h treatments decreased compared to control, but in the root in 12h treatment, a significant expression was observed. MfNAC gene in shoot showed a significant reduction in expression in all treatments, while in root a significant increase was only observed during long-term treatment of 48h. In the present study, for first time, the expression pattern of some members of NAC gene family was examined in lentils under cold stress and the results could be useful for studies on this plant and other legumes.

Under drought stress conditions, as one of the most important limiting factors of grain yield in wheat at arid and semi-arid regions, the remobilization of assimilates gain would be more valuable to grain filling. There are a few reports on the importance of remobilization of the root during the grain filling period under drought stress conditions. An advanced mutant line of bread wheat (T-65-7-1) along with its wild type (cv. Tabasi), were planted at two moisture conditions (normal and 30-40% of field capacity) as a factorial experiment based on a completely randomized design with three replications. Sampling for gene expression analysis was conducted from the root in two stages (7 and 21 days after anthesis). In these genotypes, fructan remobilization, efficiency of fructan remobilization, and relative expression of genes involved in the synthesis and hydrolysis of fructan during the grain filling period, in root, were studied under terminal drought stress. The results showed that the stored fructan in the root participated in the assimilate remobilization. Higher fructan remobilization through root to grain in mutant line under drought stress conditions was due to over-expression of genes involved in the synthesis of fructan (1-SST and 6-SFT) at 7-days after anthesis and in hydrolysis of fructan (6-FEH) at 21-days after anthesis, compared to wild type. Drought stress did not cause a significant change in gene expression of 1-FFT and 1-FEH genes in the root of both genotypes, which confirms the only β (2,6) linkages as predominant form of fructan has affected under drought stress conditions. In wheat breeding programs, 1-SST, 6-SFT and 6-FEH can be used as molecular markers for selecting genotypes with high fructan content and more remobilization.

As one of the most dangerous heavy metals in the world, Lead impacts the metabolic and physiological activities of plants. In this study, the effect of Lead stress on proline and antioxidant enzymes activity in the roots and shoots of Hyola401 was examined in hydroponic solution. A completely randomized design experiment with three replications per treatment was carried out. Statistical analyses were conducted using SPSS software and Duncan’s test of comparison of means. Three levels of Lead took place by Pb (NO3)2 (0, 100, & 200 micromoles per liter). After seven days of treatment, plants were collected for laboratory analysis. The results showed that an increase in the concentration of Lead increased proline, soluble sugars, catalase and peroxidase activity in roots and shoots; whereas it decreased the growth parameters. These increases are an indication of plant resistance against Lead stress and play a determining role in reducing the side effects of oxidative damages.

Canola which is being used for its oil is affected by salinity stress. Salinity is one of the most important abiotic stressful conditions which affects productivity and quality of agricultural products. Pseudomonas fluorescens is a Plant growth promoting rhizobacteria having symbiotic relation with plants that reduces adverse effects and increases plant growth. In this study salinity stress has been applied in two levels (0 and 300 mM NaCl). Absence and presence of P. fluorescens was the other treatment applied to plant root with three replications. Statistical analysis was carried out as split plot based on completely randomized design. In order to evaluate proteome analysis of canola root under salinity stress inoculated with P. fluorescens 2D-PAGE approach was carried out. To reach this goal proteome extract of root was extracted via TCA-acetone method. Isoelectric focusing and SDS-PAGE for 1st and 2nd dimensions, were used, respectively. Acquired gels were analyzed using PD-quest software after staining with silver nitrate. Results demonstrated 216 spots on the gels. Sixteen spots showed significant change as result of salinity stress. Thirteen spots showed change in quantity as result of presence of P. fluorescens FY32. After applying salinity and inoculation PGPR, 23 spots presented changes significantly. After identification of proteins using molecular weight and PI, it has been recognized that most of the responding proteins to salinity and PGPR presence conditions are categorized in metabolic/ energy related pathways. Then, signaling, maintenance/ defense, channel proteins and protein structure/ location related proteins were the ones that had high frequency respectively.

Catharanthus roseus is a medicinal plant containing very important alkaloids such as Vincristine and Vinblastin that are used to treat a variety of cancers. Due to the importance of the plasticity genes such as rolC in the biosynthesis of alkaloids, this study we investigated possible improvement of rooting and root induction in C. roseus using the rolC gene. To this end, the seeds of this plant were superficially sterilized and cultured in in vitro conditions. The leaf explants of these in vitro plants were inoculated by Agrobacterium tumefaciens carrying pBI121-rolC plasmid (rolC under control of the CaMV 35S promoter). The inoculated explants were cultured in five different media with or without hormones for rooting. After nine days, the first roots appeared in leaf explants on the MS medium without hormones and containing cefotaxime antibiotic. Two lines had very rapid rooting and the roots branched quickly. Molecular analysis by PCR using rolC specific primers confirmed the presence of the rolC gene in the transgenic plants. Results showed that the rolC gene could be used to induce rooting in the medicinal plants and that the rolC gene is also more successful in induction of hairy roots than various different combinations of plant hormones.

Take-all disease caused by the fungus Gaeumannomyces graminis (Sacc.) Arx & Oliver var. tritici Walker is the most devastating root disease of cereals throughout the world and it has been reported from different regions of Iran including Kermanshah province. During 2010-2011, diseased samples showing white head were collected from more than 300 wheat and barley fields visited in various parts of Kermanshah province. The pathogen were recovered from diseased samples collected from 139 fields representing prevalence of take all disease in nearly half (45 percent) of visited farms. Based on geographical distribution, ninety seven isolates of G. graminis were selected for further investigation. Two sets of primer pairs (NS5: GGT-RP and NS5: GGA-RP) were used to confirm identification and differentiation of the isolates. Eighty four out of 97 isolates produced 410 bp fragments when genomic DNAs were amplified with primer pair (NS5: GGT-RP) and 400 bp fragments with primer pair (NS5: GGA-RP) confirming the identification of the isolates as G. graminis var. tritici.But, 13 isolates did not amplify any bands. To study the genetic diversity of isolates of G. graminis var. tritici, 54 isolates were selected according to their geographical origins. Genetic diversity of selected isolates was studied using ISSR markers. Tenoutof 20 ISSR primers with high polymorphism and reproducibility were selected for further studies. Cluster analysis of DNA fingerprint profiles at the best cut off point divided the isolates into three groups; but there was no clear relationship between molecular cluster grouping and geographical distribution. The results showed that ISSR marker is an appropriate marker for genetic diversity studies in isolates of G. graminis var. tritici