جستجوی مقالات مرتبط با کلیدواژه "تنش های غیرزیستی" در نشریات گروه "بیوتکنولوژی و ژنتیک گیاهی"

The ABC-transporter system is found in the three main domains of prokaryotes, eukaryotes, and fungi. Most of them mediate the active adsorption or release of specific molecules into biological membranes. So far, a comprehensive study on the expression pattern of ABC-transporter genes has not been done. The genes were selected based on biological function, and the pattern of relative gene expression in different stolon development stages in responses to heat (29°C), cold (4°C), ABA (50, 75 and 100 µM) and control (greenhouse conditions) were studied. In order to evaluate the relative changes in the expression of StABC transporter genes in response to abiotic stresses, real-time PCR was used. The effect of cold stress on the relative changes expression of StABC transporter genes in different stages of potato development showed that StABC-012 and StABC-002 genes have increased expression and StABC-001, StABC-024, StABC genes-002, StABC-124, StABC-138 had high expression level in response to heat stress and ABA all StABC transporter genes at different developmental stages had lower expression than control conditions. StABC-084 and StABC-138 genes in 50 μM treatment of ABA in the first developmental stage and StABC-084, StABC-001 and StABC-124 genes in 75 μM in the third developmental stage and StABC-024 in 100 μM ABA in the first stage have a higher expression relative to other developmental stages. The third development had a higher expression other developmental stages. Also, to ensure the effect of abiotic stresses on the potato plant, the amount of proline (mg/g FW) and ABA (ppm) in different stages of stolon development were measured and evaluated. The content of proline levels also increased at different developmental stages. In heat stress, the amount of proline in the first, second and third developmental stages were 41.24, 67.2 and 21.48 mg /g FW, respectively. Also, the amount of proline in different time levels of cold stress (temperature 4°C) showed a significant increase. so that, in the first developmental stage at the treatment level of 48 hours (76.92 mg / g fresh weight) the highest and third development stage had the lowest proline content at the treatment level of 48 hours (44.58 mg / g fresh weight). The results of ABA assay show a significant difference with control; in a concentration of 50 μM, showed the highest increase in the third developmental stage (0.777 ppm). Also, by increasing the hormone concentration to 75 μM, the amount of ABA in the second developmental stage compared to the control conditions by 0.0073 ppm shows an acceptable increase. The aim of this study was to investigate the relative changes in the expression pattern of ABC transporter genes at different stages of development stolon in response to cold, heat and ABA stresses. The findings of this study improve the understanding of the function of the ABC transporter gene family and facilitate further studies on the detailed molecular and biological function of potatoes.

ABC transporters (ATP-binding cassettes) are among the largest gene families found in the three domains of bacteria, eubacteria, and eukaryotes. Most known ABC proteins are ATP-dependent, and membrane transporter and transport a wide range of molecules. These carriers play an important role in various biological processes. Since no comprehensive study has been performed on the identifying of ABC transporters in the potato plant, in this study, by searching the NCBI database and screening the identified genes, 228 ABC transporter genes were finally identified. Analysis of gene ontology (GO) showed that about 53% of ABC transporters in biological processes are responsible for transporting materials. In the analysis of molecular function and cell content, it was found that 32% are ATP-binding and 43% of them are inner membrane actuators, respectively. Also, the Cis elements in the promoter of ABC transporter genes was investigated, which finally identified 13 elements in drought stress and three elements in salinity stress. Finally, the expression pattern of eight selected ABC transporter genes under drought and salinity stresses was investigated using qPCR method. The results showed the effect of the studied genes under stress. StABC-050, StABC-084 and StABC-124 genes in drought stress and StABC-084 and StABC-001 genes had high expression in salinity stress. Then, to ensure the application of the applied stresses, the amount of proline and RWC and Na+/K+ were measured. According to the results, with increasing drought stress, the amount of proline in different developmental stages increased and RWC decreased, so that this decrease showed a significant difference at the level of 1%. The aim of this study was to identify and evaluate the expression pattern of selected ABC transporter genes under drought and salinity stresses in potato.

MicroRNAs are a large class of small and non-coding RNAs that regulate gene expression by binding target mRNA, which leads to cleavage or translational inhibition. Plant miR164 family is highly conserved and is involved in the responses of plants to biotic stresses through the regulation of their target NAC genes. In the present study, 68 putative NAC domain-encoding genes (NACs) were identified in Aeluropus littoralis, a halophyte plant of family Poaceae. Among the AlNAC genes identified, 4 were predicted putative targets for regulation by miR164. The high conservation of miR164 recognition sites in AlNAC genes indicates the essential role of target sites in the normal function of these genes as transcription factors. Expression profile of AlNAC1L.1 candidate gene in response to salt and drought stresses and ABA phytohormone in leaf, stem and root tissues was analyzed by RT-qPCR. The results showed that AlNAC1L.1 gene down-regulated in all tissues at 6 hours after applying stresses. Among the treatments, 600 mM NaCl treatment reduced AlNAC1L.1 expression in leaf, stem and root tissues to about -217, -26 and -9 folds, respectively. Therefore, the AlNAC1L.1 which is ortholog of known Oryza miR164-targeted NAC gene OMTN6, may play negative regulatory role in response to salt, drought and ABA treatments. These results indicated that function of some NAC proteins might be conserved among species. Collectively, these findings provided a useful resource for further analysis of the interactions between NAC genes and their intricate regulation by miR164 in response to abiotic stresses.

Environmental stresses affect the growth and development of crops during the growing season. Soil salinity is one of the most important environmental stresses that reduce crop yield. Understanding the mechanisms of coping with stress in plants at the molecular level can be effective in providing an efficient way to improve stress-tolerant plants. To save energy, plants do not express all their genes, simultaneously. Rather, depending on environmental conditions, they activate genes that are needed in a particular situation. For instance, in response to salinity stress, the expression of several genes in plants including HKT1 and NHX1 transporters is changed. In this study, variation in the expression of ZmHKT1 and ZmNHX1 genes along with the ZmMYB30 transcription factor were investigated in two salt-tolerant and salt- sensitive maize lines with real time polymerase chain reaction technology.

Maize salt-tolerant line (P14L2) and salt-sensitive line (MO17) seeds were grown in plastic pots containing perlite and peat moss in 2:3 ratios under controlled conditions in growth chamber, and Hoagland solution was used to irrigate plants. In the eight-leaf stage, salinity stress from NaCl source was gradually applied to half of the pots starting from a concentration of 5 ds/m for three days, and from the fourth day onwards, salt stress was applied at a concentration of 8 ds/m for 7 days. The other half was used as control. Then, 24 hours (as short-time salt stress) and 7 days (as long-time salt stress) after the salinity stress, the roots and leaves of the plants were sampled in liquid nitrogen. RNA extraction was performed from leaf and root samples, and cDNA was then synthesized. Gene expression was assessed with real-time PCR. The Actin gene was used as the reference gene. The experiment was performed in 2 biological (experimental) and 3 technical (laboratory) replicates. Finally, the changes in the expression of genes were measured.

Increased expression of ZmNHX1 gene in root tissue during the short-time and in leaf tissue during the long-time in the tolerant line, and also increased expression of ZmHKT1 gene in the root tissue during the long-time in the tolerant line compared to the sensitive line probably indicate a positive role of these genes in resistance to salinity stress in maize. The highest relative expression of MYB30 gene in both tolerant and sensitive lines was related to root tissue during the short-time, which over time a significant decrease in the expression of this gene was observed in both lines.

The results of this study can be potentially useful in maize breeding programs to produce salinity resistant cultivars.

Choline Monooxygenase (CMO) enzyme is a key component of glycine betaine (GB) biosynthesis pathway, playing important role in plant's biochemical adaptation to abiotic stresses. In plants, GB is synthetized by a two-step oxidation of choline (Cho) catalyzed by the CMO enzyme in the first step. According to the Arabidopsis thaliana genome database (TAIR) there is an AtCMO-like gene probably encoding for the Cho oxidizing enzyme to the GB. In this study, we used relative expression analysis via quantitative Real-Time PCR (qRT-PCR) to evaluate the effects of salinity stress, drought stress, and osmotic stress on the expression pattern of the gene in Arabidopsis thaliana tissues including fast-expanding leaves, fully expanded leaves, and roots. In general, the expression pattern of AtCMO-like gene varied through studied tissues in response to the different abiotic stresses. While the gene expression was affected mostly as the lack of changes and/or down-regulation; the only prominent up-regulation observed in fast expanding leaves and roots by about 3 and 1.9 folds, respectively, in response to the first level of salinity stress. We conclude that the AtCMO-like gene seems to negligibly influence the response to salinity stress, drought stress, and osmotic stress in Arabidopsis.

Abiotic stresses are among major factors limiting crop yields, and SnRK2 protein kinases are one of the key regulators of plant response to abiotic stresses. Due to the economic importance, cultivation area, and tolerance of barley to the abiotic stresses, identification and characterization of SnRK2 family members in barley is performed in present research. SnRK2 conserved sequences were used as a query for tBLASTn analysis in different databases such as NCBI and international barley sequencing consortium against all of the reported barley sequences. As a result, 10 members were identified (HvSnRK2.1 to HvSnRK2.10) which 8 of them were not yet reported. These HvSnRK2 members were aligned with AtSnRK2s and OsSnRK2s and a phylogenetic tree was constructed. Detection of chromosomal localization, promoter analysis and gene structure determination was also performed. Half of the family members were located on chromosome 2 and the rest on chromosomes 1, 4, 5 and 6. Number of introns in the gene family members varied from 0 to 8. Totally, 19 sorts of cis elements including abiotic stress responsive elements were found in HvSnRK2s promoter sequences. Expression pattern of the family members were evaluated in different tissues, treatments and genotypes, based on the microarray data. Expression of HvSnRK2.6 was up-regulated by drought, salt and cold stresses implementing its important role in signal transduction of these stresses and tolerance induction to them. It is expected that this gene could be used in plant manipulation and breeding programs aimed for tolerance enhancement to abiotic stresses especially drought.

Abiotic stresses such as drought, cold and salinity have negative effects on yield and growth plant, so tolerance to them has been main target of plant breeders. DREB transcription factors are member of AP2/ERF family. Analysis of promoter region of genes which responsive to drought and low temperature stresses and ABA-independent, led to the discovery of 9pb region with TACCGACAT sequence that named DER. Proteins which are encoded by DREB genes have attached to this sequence and regulate gene expression. WDREB2 or TaDREB gene expression is induced by drought, cold, abscisic acid and salinity stresses. This gene was transferred to wheat using Agrobacterium-mediated gene transformation method. Molecular analysis with PCR technique confirms that 20 plants out of 40 plants are transgenic. Also gene expression analyses with Real-Time PCR Technique have showed that the most part of transgenic plants have increased expression between 2 to 19 times, more than non-transgenic plants. This increasing of expression which demonstrate the efficiency of 35S promoter in monocot plants, can lead to the raising of expression in downstream genes and enhancement of tolerance to environmental abiotic stresses.