Yazar "Khabbazi, Saber Delpasand" seçeneğine göre listele

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    DEVELOPMENT OF INSECT-RESISTANT COTTON LINES WITH TARGETED EXPRESSION OF INSECTICIDAL GENE
    (INST BIOLOSKA ISTRAZIVANJA SINISA STANKOVIC, 2016) Bakhsh, Allah; Anayol, Emine; Khabbazi, Saber Delpasand; Karakoc, Omer Cem; Sancak, Cengiz; Ozcan, Sebahattin
    In order to address biosafety concerns regarding the constitutive expression of foreign genes in crops, we applied a strategy aimed at confining foreign gene expression in insect wounding sites of cotton. For this purpose, a plant expression construct was designed by cloning the AoPR1 promoter (pathogenesis-related protein gene isolated from Asparagus officinalis) upstream from the insecticidal gene cry1Ac. The Turkish cotton cultivar cv. STN-468 was transformed using the Agrobacterium tumefaciens strain LBA4404 containing the recombinant binary vector pRD400 harboring cry1Ac under a wound-inducible promoter. The neomycin phosphotransferase (nptII) gene was used as a selectable marker at a concentration of 100 mg/L. The primary transformants were analyzed for T-DNA integration and expression using standard molecular approaches. The efficacy of insecticidal gene control of the AoPR1 promoter was investigated using leaf bioassays with 2nd instar larvae of Helicoverpa armigera and Spodoptera littoralis. Positive primary transformants from T-0 progeny were further raised under greenhouse conditions to obtain progeny (T-1). The introduced gene was properly inherited and expressed in T-1 progeny. The mechanical wounding of plants resulted in increased cry1Ac protein levels during 0-48 h of the wounding period. The transgenic lines exhibited appreciable levels of resistance against targeted insect pests in the leaf bioassays. The use of a wound-inducible promoter to drive insecticidal gene expression is a valuable insect resistant management strategy as gene expression will remain limited to the insect biting sites of plant and crop, food and environmental concerns can be minimized.
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    Insect-resistant transgenic crops: retrospect and challenges
    (TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2015) Bakhsh, Allah; Khabbazi, Saber Delpasand; Baloch, Faheem Shahzad; Demirel, Ufuk; Caliskan, Mehmet Emin; Hatipoglu, Rustu; Ozkan, Hakan
    The advent of genetic engineering has revolutionized agriculture remarkably with the development of superior insect-resistant crop varieties harboring resistance against insect pests. Bacillus thuringiensis (Bt) has been used as a main source for insect-resistant genes. In addition to Bt endotoxins, various plant lectins and other non-Bt genes from different sources have also been introduced in crop plants of economic importance. The insect-resistant crops have made a huge economic impact worldwide since their commercial release. The cultivation of insect-resistant cultivars has resulted both in increased crop productivity and in decreased environmental pollution. Although insect-resistant crops have been allowed to be commercialized following proper biosafety guidelines and procedures, still these crops face many challenges in order to be fully adopted and accepted. The degradation kinetics of Bt proteins, horizontal and vertical gene flow, effects on nontarget insects or organisms, antibiotic resistance, and some other unintended effects have been noted and discussed. Although no concrete evidence regarding any significant hazard of genetically engineered crops has been presented so far, the debate still remains intense. Impartial and professionally competent regulatory mechanisms for the evaluation of insect-resistant and other transgenic crops must be fully functionalized. The first part of this review focuses the development of different insect-resistant crops and various strategies adapted to delay resistance development in insect pests, while the second part addresses the challenges and future prospects of insect-resistant crops.
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    Molecular Characterization of Snowdrop Lectin (GNA) and its Comparison with Reported Lectin Sequences of Amaryllidaceae
    (CZECH ACADEMY AGRICULTURAL SCIENCES, 2016) Khabbazi, Saber Delpasand; Bakhsh, Allah; Sancak, Cengiz; Ozcan, Sebahattin
    Plant lectins have become efficient sources of insect resistance in crops. The present study was conducted to identify, amplify, clone and characterize the plant lectin gene GNA. The lectin, present in Galanthus nivalis (snowdrop), is an agglutinin toxic to hemiptera. The attempt was made to elucidate the relationship of the lectin gene trGNA (GNA isolated and characterized from Turkey) with other previously cloned lectins having insecticidal activity and to ensure the presence of the conserved mannose-binding region/site in the gene sequence. The full-length cDNA of trGNA was 477 bp that contained a 333 bp open reading frame encoding 157 amino acid proteins with 23 amino acids of signal peptide. BLAST results showed that trGNA has 89-97% similarity with previously reported GNA sequences while it has 84-96% similarity with earlier reported GNA protein sequences. No intron was detected within the region of genomic sequence corresponding to trGNA full-length cDNA. According to the search results from the NCBI (National Centrer for Biotechnology Information database), trGNA from Galanthus nivalis is most similar to the previously reported lectin sequences of Narcissus tazetta with a similarity percentage of 87%. The obtained results are useful for engineering of plants with enhanced insecticidal activity against chewing and sucking insects, causing crop pests. In addition, medical application of lectins may also be considered.