Includes a title page in Arabic

Thesis (Ph.D.) Doctoral Egypt - Japan University of Science and Technology (E-JUST) - Basic and Applied Science (BAS) Institute - Biotechnology Department 2025

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Jojoba shrubs as medicinal plants are cultivated in arid and semiarid lands and racterized by tolerance to drought, salinity, and high temperatures Microorganisms associated h such plants are attributed to plant growth-promoting (PGP) and the production of bioactive npounds with medical applications Previous studies showed the importance of jojoba as jojoba in the agricultural field ; however, no prior study discussed the role of jojoba associated croorganisms in reflecting plant health , biocontrol and exploring their production for bioactive npounds Here , the culture-independent and culture-dependent approaches were performed to dy the diversity of the jojoba-associated microorganisms The Internal Transcribed Spacer (ITS) tagenome analysis revealed the existence of four fungal phyla : Ascomycota , Aphelidiomycota , sidiomycota, and Mortierellomycota The phylum Ascomycota was the most common and had e highest relative abundance in soil, root, branch, and fruit samples (59.7%, 50.7%, 49.8%, and 1.4%, respectively) Alternaria was the most abundant genus in aboveground tissues : branch 3.7%) and fruit (32.1%), while the genus Discosia had the highest abundance in the underground mples: soil (24%) and root (30.7 %) Furthermore , the analysis of FUNGuild revealed the bundance of symbiotrophs over other trophic modes , and the guild of endophytes was commonly ssigned in all samples For the analysis of 165 metagenome, the major phyla were Cyanobacteria , roteobacteria , and Actinobacteria At the level of genus, Sphingobium was abundant in soil amples (6%) , while Calothrix was abundant in all the inside jojoba's tissues (78.5% for roots, 5.5% for branches, 92.4% for leaves , and 86% for fruits). For the culture dependent method , a >tal of 66 isolates were isolated , identified , and screened for their chitinolytic, antagonist activity gainst three phytopathogenic fungi (Fusarium oxysporum , Alternaria alternata and Rhizoctonia olani) and antibacterial activity Therefore , 12 strains were selected and molecularly identified Based on ITS and 16S rRNA sequence analysis , the selected potent isolates were molecularly dentified as Aspergillus stellatus EJ-JFF3 , Aspergillus flavus EJ-JFF4 , Stilbocrea sp. EJ-JLF1 Fusarium solani EJ-JRF3 , Amesia atrobrunnea EJ-JSF4 , Bacillus velezensis EJ-JBBI , Bacillus pumilus EJ-JBB3, Enterobacter sp. EJ-JFB12, Psychrobacter sp. EJ-JSB4, Bacillus amyloliquefaciens EJ-JBA2 , Bacillus subtilis EJ-JRA4 , Streptomyces sp. EJ-JSA3 The endophyte strain A. flavus EJ-JFF4 exhibited the highest chitinolytic activity (9 Enzyme Index) and antagonistic potential against Fusarium oxysporum , Alternaria alternata , and Rhizoctonia solani

إن النباتات الطبية و البرية غنية بالكائنات الحية الدقيقة المرتبطة بها و التي يمكن أن تنتج مركبات نشطة بيولوجيا مختلفة و تحتوي شجيرات الجوجوبا على كائنات حية دقيقة مختلفة (بكتيريا، وبكتيريا أكتينو بكتيرية، وفطريات) أظهرت نشاطاً في تعزيز نمو النبات (للأغراض الزراعية) وأنشطة مضادة للبكتيريا و مضادة للسرطان (للأغراض الطبية) و قد أظهرت سلالة الرشاشة الصفراء JFF4. سلالة قوية لاستخدامها كعامل مكافحة حيوية كما أنه يمكن استخدام سلالة-Bacillas pumilur El BB3 و Bacillus anylalolignefaciens El-BA2 و Streptomyces sp. El-JSA3 كمصدر لإنتاج المضادات الحيوية كما أنه يمكن ايضا استخدام سلالات Bacillus any laloliquefaciens El- Bacillas panilas El-B33 BA2لإنتاج مستقلبات يمكن استخدامها كأدوية مضادة للسرطان ولمزيد من العمل، يوصى بتطوير تقييم سلالة Aspergillus fans ElJFF في تجارب الصوب البلاستيكية ثم التجارب الحقلية بالإضافة إلى ذلك، يوصى بتقييم المركبات التنقية المعزولة من المستخلصات البكتيرية الخام في المختبر ثم إجراء التجارب على حيوانات التجارب تمهيدا لاعتمادها واستخدامها بين البشر

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