Document Details

Document Type : Thesis 
Document Title :
ISOLATION AND CHARACTERIZATION OF VIRULENT GENES IN SHRIMP VIRUSES IN SAUDI ARABIA
عزل و توصيف جينات الضراوة في فيروسات الروبيان في المملكة العربية السعودية
 
Subject : faculty of science 
Document Language : Arabic 
Abstract : Shrimp industry is one of the important sectors in the kingdom of Saudi Arabia (KSA) and it has shown steep production with great economic values. WSSV is a major pathogen which causing 100% mortality and economic losses in world wide. In KSA two most important species such as Litopenaeus vannamei and Fenneropenaeus indicus were cultured widely. Due to the sheer expansion of shrimp culture industry, WSSV occurrences was found in F. indicus and followed by White Spot Syndrome Virus outbreak, SPF L. vannamei was imported and cultured in KSA with stringent biosecurity measures implied by ministry of water, environment and agriculture (MEWA). WSSV is highly virulent pathogen infect several crustaceans including crab and crayfish. rr1, rr2, VP28 and VP26 are the major structural and non-structural proteins of WSSV have role in WSSV systemic infection as well as pathogenesis in shrimp. In this study we applied molecular technique to identify the virulence related genes such as VP28 and VP26 from Saudi Arabia subsequently sequence based functionality were derived. The full-length of VP28 and VP26 obtained from SA isolates of WSSV and the sequences showed 99-100% homology with other WSSV known isolates. The identified gene sequences VP28 and VP26 contain an ORF of 615 bp and 612 bp encoding 204 and 203 amino acids respectively. Saudi Arabia WSSV isolates of VP26 amino acid sequences do not differ from known isolates in GenBank data base, whereas VP28 confirmed that a single amino acid differed, as a result of the substitution of G to D (Glycine to Aspartic acid). The phylogenetic analysis revealed that VP26 gene had a greater homology with other isolates of VP26; however, VP28 phylogenetic tree shown a subphylum among the isolates, in particular with Egypt and Thailand isolates. Putative conserved domain which codes for VP28 of WSSV superfamily and 3D form of structural relationships with the VP28 and VP26 amino acid sequences of WSSV Saudi Arabia isolates were generated. We anticipate that the present study will be helpful to reveal the genetic linkage between the isolates and to study the epidemiological relevance in harsh environmental conditions in Saudi Arabia. In the present study, in an attempt made to obtain the virulence related genes encoding the large (rr1) and small (rr2) subunit of ribonucleotide reductase from WSSV isolates of KSA. Litopenaeus vannamei and Fenneropenaeus indicus samples were collected from Jazan region and stored in -80°C for the analysis. The WSSV infection was confirmed by OIE protocol. Amplification and sequencing of rr1 (2550bp) and rr2 (1242 bp) genes were done using gene specific primers. Subunits of rr1 and rr2 fragments were identified KSA isolates for the first time. The rr1 and rr2 sequences had significant identity (98-100%) with other known sequences in BLASTX and the sequences were matched with conserved domain family of Ribonucleotidereductase (RNR). The phylogenetic analysis revealed that sequences had greater homology with other isolates of WSSV Ribonucleotidereductase family and it was formed as monophylectic clade. The obtained information so for from the sequences of rr1 and RR2, supports that the family of RNR was highly conserved among WSSV isolates. 
Supervisor : Dr. Mohammad Ishtiaq Qadri 
Thesis Type : Doctorate Thesis 
Publishing Year : 1441 AH
2019 AD 
Added Date : Sunday, December 22, 2019 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
علاء الدين حمد حكميHakami, Alaudeen HamadResearcherDoctorate 

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