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تحديد تعبير الجين المتحمل للملوحة TaGSK1 في عدد من اصناف الحنـطـة == Determination of Gene Expression of Salt Tolerant Gene Tagsk1 In Wheat Cultivars
Author name:
ايمان نعمان اسماعيل
Supervisor name:
نورية عبد الحسين علي | مجيد ارشيد سباح
General topic:
Biology
Specific topic:
Biotechnologies
Degree:
Master
University:
University of Baghdad
Language:
Arabic
University location:
Baghdad
First pages:
24T2861 - p.pdf
Abstract:
نفذت الدراسة الحالية في مركز بحوث التقنيات الاحيائية/ جامعة النهرين للمدة 2011 - 2012 لغرض الكشف عن جين الملوحة TaGSK1 ودراسة التعبير الجيني له في صنفين من الحنطة فرات ودجلة والتركيب الوراثي 2H المنتخبة لصفة تحمل الملوحة مقارنة مع الصنف تموز2 الحساس للملو | This study was conducted in biotechnology research center, Al - Nahrain university in 2011 - 2012 to detect the gene responsible for salt tolerant (TaGSKI) and study its expression in two wheat (Tigris and Euphrates) cultivars and the genotype (2H) were selected for salt tolerance through improvement and breeding programs as compared with to the sensitive local wheat cultivar (Tamooze 2). Seeds of the these cultivars were sown in flasks that contained Ms media in three salt levels (0, 15, 25) ds/m with three replication for each. Five seeds from each cultivars were sown in each replicate. After 10 - 15 days from the sowing, the percentage of germination was estimated, and samples of leaves were collected for RNA extraction and then changed to the cDNA. B - actin gene that consider endogenous control and salt tolerant gene TaGSK1 were amplificated by using PCR technique to discover the gene and by QPCR to estimate gene expression by determine the CT (Cycle Threshold) value for B - actin and TaGSK1 genes in wheat plants of the studying cultivars. Number of DNA dilutions of 189bp molecular weight that extracted from agarose gel were used to determing CT value for each dilution. Standard curves were drawn to find out value of PCR Efficiency which was used for gene expression for the salt tolerant gene TaGSK1.The results of germination percentage (%) showed that there were high differences between the two salt tolerant cultivars (Tigris and Euphrates) and 2H genotype and local cultivar (Tamooze 2). Euphrates cultivar gave 100% germination percentage, and the Tigris cultivar and 2H genotype gave 89, 86% germination percentage respectively at 25ds/m. whilst the local cultivar gave zero germination percentage at the same level of salinity. At 15ds/m level, also the Euphrates cultivar gave 100% germination percentage while the Tigris cultivar and 2H genotype gave 96, 94% germination percentage respectively as compared to Tamooze cultivar that gave 13% germination percentage. All the cultivars have 100% germination percentage at 0.0ds/m level. The conclusion of this result is the two cultivars (Tigris and Euphrates) and 2H genotype more salt tolerance than local cultivar at this growth stage which more salt sensitive than others growth stages. The results of PCR reaction were also indicated that Tigris and Euphrates cultivars and 2H genotype have salt tolerant gene TaGSK1, while this gene did not exist in the local cultivar. There were two bands of TaGSK1 gene that have 189bp and 404bp molecular weight in the Tigris and Euphrates cultivar and the genotype 2H, while the local cultivars have only one band that have 404bp molecular weight. These results were indicated that 189bp molecular weight of this gene is responsible for salt tolerance character in these cultivars.The results of QPCR reaction also were revealed that there is difference between the cultivars in their gene expression. Tigris and Euphrates cultivars and 2H genotype gave the highest gene expression at 15ds/m and increased at 25ds/m as compared to 0.0ds/m. At the second level 15ds/m the gene expression of the two cultivars and genotype was 0.8682, 0.8190 and 0.8688 respectively, and at the third level 25ds/m was 1.656, 1.3176 and 1.2665 respectively, while at the first level 0.0ds/m was less than the other 15, 25 ds/m as compared to local cultivar that the gene salt tolerant (TaGSK1) have no gene expression at the same salt levels. This result indicated that the local cultivar does not have salt tolerant gene TaGSK1. From these results we can revealed that TaGSK1 gene was found in the Tigris and Euphrates cultivars and 2H genotype, and this gene can be considered from high salt tolerant gene, because it gave the highest gene expression at the highest salt level 25ds/m. Therefore this gene help the plant to tolerate salt stress and grow very well. The results also showed that the two salt tolerant cultivars (Tigris and Euphrates) and the salt tolerant genotype (2H) proximately have the same salt tolerance degree, so they have proximately the same gene expression as compared to salt sensitive local cultivar which have no salt tolerant gene TaGSK1. This gene is good indicator for salt tolerance at high salinity levels 15, 25 ds/m in these cultivars and genotype.
