Rasha Ahmed Ahmed Ali Elmoreigi, <br/><br/>
Isolation of the dehydrin 1 (Dh1) gene from mangrove (Avicennia marina L) and transformation in apricot / 
 عزل جين الديهيدرين 1 (Dh1) من المانجروف (Avicennia marina L.) ونقله إلى أصل من المشمش (Prunus armeniaca L.) 
by  Rasha Ahmed Ahmed Ali Elmoreigi ; Supervisors Dr. Ebtissam Hussein Aly Hussein, Dr. Shereen Abu El-Maaty Mohamed, Dr. Sabah Anwar Hassanen. 
 - 152 pages :   illustrations ;   25 cm. +   CD. 
<br/><br/>Thesis (Ph.D)-Cairo University, 2025. 
<br/><br/>Bibliography: pages 134-152. 
<br/><br/> Improvement of fruit trees to withstand abiotic stress is becoming a major <br/>goal to mitigate the threatening effects of the climatic changes on fruits <br/>productivity. Apricot (Prunus armeniaca L.) is one of the most economic <br/>deciduous stone fruit crops globally. This study aimed to develop an efficient in <br/>vitro regeneration protocol for the Egyptian Al-Amar apricot rootstock, and laying <br/>the foundation for its genetic enhancement through introducing a dehydrin gene <br/>isolated from mangrove (Avicennia marina L.) via the agrobacterium-mediated <br/>transformation system. Two types of explants, cotyledons and hypocotyls, were <br/>cultured on 48 woody plant medium (WPM) with various concentrations of TDZ, <br/>IBA or NAA to optimize shoot induction and regeneration. Cotyledons exhibited <br/>direct somatic organogenesis, with the highest bud induction (78%) achieved on <br/>WPM containing 13.62 µM TDZ + 2.46 µM IBA. While, hypocotyls underwent <br/>indirect regeneration through callus formation, with the callusing rate (96.87%) on <br/>WPM supplemented with 15.89 µM TDZ + 1.61 µM NAA. Shoot proliferation <br/>was most successful on media with 8.87 µM BAP and 0.54 µM NAA, with <br/>hypocotyls producing more shoots per explant than cotyledons. Optimal rooting <br/>occurred on WPM with 9.80 µM IBA. In parallel, the full-length of the dehydrin <br/>gene DHN was isolated from Avicennia marina via RT-PCR and cloned into <br/>pGEM-T Easy vector for sequencing and subsequently cloned into the pRI 201-AN <br/>plant expression vector. This construct was introduced into Agrobacterium <br/>tumefaciens LBA4404. Al-Amar cotyledon and hypocotyl explants were co-<br/>cultivated with Agrobacterium, followed by selection on media containing <br/>kanamycin and cefotaxime. For cotyledons, the highest survival rate (54.1%) was <br/>observed with 500 mg/l cefotaxime and 100 mg/l kanamycin and buds induction of <br/>20.9% was achieved on 400 mg/l cefotaxime and 50 mg/l kanamycin. In contrast, <br/>hypocotyls showed better survival on 500 mg/l cefotaxime and 50 mg/l kanamycin, <br/>but had limited callus formation. PCR screening confirmed the presence of the <br/>DHN gene in transformed tissues. The transformation efficiency of buds derived <br/>from cotyledons and calli induced from hypocotyls was 1.04% and 0.50%, <br/>respectively. This study represents the first attempt to develop an Egyptian <br/>transgenic apricot rootstock with improved salinity tolereance which could pave <br/>the way for producing non-transgenic apricot fruits under adverse conditions via <br/>transgrafting.   تم تأسيس برتوكول فعال لإعادة التكشف معملياً لأصل المشمش المصري (العمار) باستخدام نوعين من المنفصلات النباتية وهي: الفلقات والتي أظهرت تخليق الأعضاء الجسدية المباشر  دون تكوين كالس وقد بلغت أعلى نسبة لتكوين البراعم (78%) و المنفصلات السويقة الجنينية والتي اتجهت للتخليق الغير مباشر للأعضاء النباتية من خلال تكوين الكالس ثم البراعم حيث بلغت أعلى نسبة لتحفيز انتاج الكالس (96.87%)، بالتوازي تم عزل جين الديهيدرين (DHN) الكامل من نبات المانجروف باستخدام تقنية النسخ العكسي (RT-PCR) ، وكلونته في ناقل التعبير الجيني في النبات pRI 201-AN  ثم ادخاله إلى بكتريا الأجروباكتريم والتي استخدمت لاحقاً في التحول الوراثي لأصل المشمش "العمار" و بلغت كفاءة التحول الوراثي للبراعم الناتجة من الفلقات والكالس الناتج من السويقات الجنينية 1.04% و 0.50% على التوالي. 
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<br/><br/><br/>Text in English and abstract in Arabic & English. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Genetics<br/>الوراثة
<br/><br/><label>Subjects--Index Terms: </label>Apricot rootstock  Cotyledon  Hypocotyl  Explant type,   Prunus armeniaca  in vitro  regeneration  DHN gene  Avicennia marina  إعادة تكشف النباتات معملياً  أصل المشمش 
<br/><br/><label>Dewey Class. No.: </label>576.5