Rozprawy doktorskie na temat „Plant gene silencing”
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McMaster, S. "Studies on Gene Silencing in Plant Parasite Nematodes". Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501370.
Pełny tekst źródłaGeorge, Gavin M. (Gavin Mager). "Virus induced gene silencing for the study of starch metabolism". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4024.
Pełny tekst źródłaENGLISH ABSTRACT: Virus Induced Gene Silencing (VIGS) was optimized to allow for the study of starch metabolism. The plastidial inorganic pyrophosphatase gene, for which a mutant has never been identified, was studied using VIGS and it was found to have a broad role in this subcellular compartment. The accumulation of inorganic pyrophosphate limited the production of starch, carotenoids, chlorophyll, and increased the plants susceptibility to drought stress. These effects highlight the importance of this enzyme in maintaining a low intraplastidial concentration of PPi providing an environment which facilitates these anabolic processes. Several genes involved in starch synthesis and degradation were also targeted with the aim of establishing a system of multiple gene silencing for the study of metabolic pathways. One, two and three genes were successfully silenced using this system which was validated based on previously published data. Interestingly, simultaneous silencing of the two isoforms of disproportionating enzyme led to a novel phenotype as a large reduction in starch instead of the expected increase was observed.
No Afrikaans abstract available
Dalzell, J. J. "The development of gene silencing strategies for plant parasitic nematodes". Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546037.
Pełny tekst źródłaChau, Ling Bess. "Capacity of plant-derived siRNA for gene silencing in mammalian cells". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36778874.
Pełny tekst źródłaChau, Ling Bess, i 周玲. "Capacity of plant-derived siRNA for gene silencing in mammalian cells". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36778874.
Pełny tekst źródłaDavies, Gareth John. "Co-suppression of chalcone synthase genes in Arabidopsis thaliana". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318010.
Pełny tekst źródłaRaponi, Mitch Biochemistry & Molecular Genetics UNSW. "Antisense RNA-mediated gene silencing in fission yeast". Awarded by:University of New South Wales. Biochemistry and Molecular Genetics, 2001. http://handle.unsw.edu.au/1959.4/18277.
Pełny tekst źródłaStarkus, Laura. "Virus-induced gene silencing of putative Diuraphis noxia (Kurdjumov) resistance genes in wheat". Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4193.
Pełny tekst źródłaGammelgård, Elin. "Interactions of potato virus A with host plants : recombination, gene silencing and non-hypersensitive resistance /". Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007111.pdf.
Pełny tekst źródłaBuchmann, Cody. "Reversal of RNA-mediated gene silencing pathways by geminivirus AL2 and L2 proteins". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1221847080.
Pełny tekst źródłaMendu, Venugopal. "ROLES OF MICRORNAS IN PLANT ABIOTIC STRESS, DEVELOPMENT AND VIRAL INFECTION". UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/663.
Pełny tekst źródłaFultz, Dalen R. "The Silencing of Endogenous and Exogenous Transposable Elements in Arabidopsis". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492468003210374.
Pełny tekst źródłaCreasey, Kate M. "Investigating the roles of arabidopsis polycomb-group genes in regulating flowering time and during plant development by (I) challenging silencing and (II) developing approaches to dissect Pc-G action". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4025.
Pełny tekst źródłaNauth, Brittany J. "Soybean QTL Mapping and Candidate Gene Identification for Pythium irregulare and Phytophthora sojae Partial Resistance; and Root-Knot Nematode Induced Suppression of Gene Silencing". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406151869.
Pełny tekst źródłaHe, Jie. "Isolation of An ARGONAUTE Gene in Pelargonium and Identification Of Candidate Genes Regulated Through ARGONAUTE4-Dependent RNA-Dependent DNA Methylation In Arabidopsis". Connect to full text in OhioLINK ETD Center, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1260812913.
Pełny tekst źródłaTypescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy degree in Biology." Bibliography: leaves 54-56, 91-95, 118-119, 133-139.
El-Habbak, Mohamed H. "OVEREXPRESSION/SILENCING OF SELECTED SOYBEAN GENES ALTERS RESISTANCE TO PATHOGENS". UKnowledge, 2013. http://uknowledge.uky.edu/plantpath_etds/8.
Pełny tekst źródłaChakrabarti, Manohar. "EVOLUTIONARY PERSPECTIVE OF NICOTINE TO NORNICOTINE CONVERSION, ITS REGULATION AND CHARACTERIZATION OF EIN2 MEDIATED ETHYLENE SIGNALING IN TOBACCO". UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/88.
Pełny tekst źródłaBiba, Angeliki. "Allele specific silencing of proteins at the neuromuscular junction". Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:92aeab4d-1339-4e69-ad3f-eab2213ed401.
Pełny tekst źródłaRupp, Jessica Lynn Shoup. "RNA interference mediated virus resistance in transgenic wheat". Diss., Kansas State University, 2015. http://hdl.handle.net/2097/20387.
Pełny tekst źródłaPlant Pathology
John P. Fellers
Harold N. Trick
Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are two viruses affecting wheat in the Great Plains region of the United States. Genetic resistance is severely limited, requiring management methods focusing on the deployment of resistant varieties and various cultural practices. Evaluation of resistance is complicated by the lack of a standard rating scale. The objective of this work was to develop new avenues to mitigate these challenges. A standardized virus symptom rating scale was developed using historical Kansas rating scales, and validated using multiple wheat populations. Two independent RNA interference (RNAi) expression vectors targeting portions of viral coat protein (CP) of WSMV and TriMV were previously transformed into wheat. T₂ plants and beyond were evaluated using PCR, reverse transcription-PCR and bioassays in which plants were challenged with their respective virus. These lines were evaluated for resistance through the T₆ generation. Crosses were made with the susceptible winter wheat cultivars, ‘Overley’ and ‘Karl 92.’ Real-time PCR results show viral titer was up to 20-fold lower in the T₆ transgenic lines, the F₁, and the BC₁F₁ compared to control plants. This provides evidence that this RNAi silencing method is stable in wheat over multiple generations. WSMV and TriMV use host eukaryotic initiation factors (eIF) in order to facilitate replication of their genomes. Previously created RNAi expression vectors were derived from the sequences of the wheat genes eIF(iso)4E-2 and eIF4G. Evaluation of these lines began in the T₁ generation. Resistance has been demonstrated in three lines of eIF(iso)4E-2 and four lines of eIF4G, derived by single seed descent. T₆ progeny co-infected with WSMV and TriMV continue to be resistant. Crosses have been performed with the winter wheat ‘Karl 92’ and three Kansas elite lines, KS030887K-6, KS09H19-2-3, and KS10HW78-1-1. RNAi construct effectiveness was evaluated using real-time PCR. Results show up to 18-fold reduction in viral titer in the transgenic lines, the F₁, and the BC₁F₁ in comparison to control plants. This research provides the first evidence that a single host transgene can provide resistance to multiple viruses and has great potential benefits to both breeders and producers.
Ho, Thien Xuan. "Antiviral gene silencing in plants". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509958.
Pełny tekst źródłaSternberger, Anne Lauren. "Figuring out Flowers: Insights Into the Mixed Breeding System of Viola pubescens". Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1584452029880175.
Pełny tekst źródłaUnver, Turgay. "Detection And Characterization Of Plant Genes Involved In Various Biotic And Abiotic Stress Conditions Using Ddrt-pcr And Isolation Of Interacting Proteins". Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609805/index.pdf.
Pełny tekst źródłaCruickshanks, Hazel Anne. "Conserved chromatin-mediated gene silencing in yeast and plants". Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/26421.
Pełny tekst źródłaBovi, Aurelie. "Investigation of novel genes, short RNAs and suppressor proteins involved in post-transcriptional gene silencing in plants". Thesis, University of East Anglia, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522400.
Pełny tekst źródłaAlphuche-Solis, Angel Gabriel. "Analysis of transgenic tomato plants with acc oxidase suppressed by sense constructs". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297991.
Pełny tekst źródłaLu, Rui. "High throughput virus induced gene silencing for the analysis of disease resistance in plants". Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398556.
Pełny tekst źródłaBuglass, Surahanil Katrin. "Regulating stem cell fate within microenvironmental niches". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:75f9498c-30f0-4983-84b2-dd58f2ccf52b.
Pełny tekst źródłaWang, Nai, i 王鼐. "Construction of a high-throughput vector for inducible gene suppression in plants and its application in control of floweringtime". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30064958.
Pełny tekst źródłaVan, Eeden C. (Christiaan). "The construction of gene silencing transformation vectors for the introduction of multiple-virus resistance in grapevines". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/53764.
Pełny tekst źródłaENGLISH ABSTRACT: Viruses are some of the most important pathogens of grapevines. There are no effective chemical treatments, and no grapevine- or other natural resistance genes have been discovered against grapevine infecting viruses. The primary method of grapevine virus control is prevention by biological indexing and molecular- and serological screening of rootstocks and scions before propagation. Due to the spread of grapevine viruses through insect vectors, and in the case of GRSPaV the absence of serological screening, these methods of virus control are not always effective. In the past several methods, from cross-protection to pathogen derived resistance (PDR), have been applied to induce plant virus resistance, but with inconsistent results. In recent years the application of post-transcriptional gene silencing (PTGS), a naturally occurring plant defense mechanism, to induce targeted virus resistance has achieved great success. The Waterhouse research group has designed plant transformation vectors that facilitate specific virus resistance through PTGS. The primary focus of this study was the production of virus specific transformation vectors for the introduction of grapevine virus resistance. The Waterhouse system has been successfully utilised for the construction of three transformation vectors with the pHannibal vector as backbone. Each vector contains homologous virus coat protein (CP) gene segments, cloned in a complementary conformation upstream and downstream of an intron sequence. The primary vector (pHann-SAScon) contains complementary CP gene segments of both GRSPaV and GLRaV-3 and was designed for the introduction of multiple-virus resistance. For the construction of the primary vector the GRSPaV CP gene was isolated from RSP infected grapevines. A clone of the GLRaV-3 CP gene was acquired. The second vector (pHann- LR3CPsas) contains complementary CP gene segments of GLRaV-3. The third vector (pHann-LR2CPsas) contains complementary CP gene segments of GLRaV-2. The cassette containing the complementary CP gene segments of both GRSPaV and GLRaV-3 was cloned into pART27 (pART27-HSAScon), and used to transform N tabacum cv. Petit Havana (SRI), through A. tumefaciens mediated transformation. Unfortunately potential transformants failed to regenerate on rooting media; hence no molecular tests were performed to confirm transformation. Once successful transformants are generated, infection with a recombinant virus vector (consisting of PYX, the GFP gene as screenable marker and the complementary CP gene segments of both GRSPaV and GLRaV-3) will be used to test for the efficacy of the vectors to induce resistance. A secondary aim was added to this project when a need was identified within the South African viticulture industry for GRSPaV specific antibodies to be used in serological screening. To facilitate future serological detection of GRSPaV, the CP gene was isolated and expressed with a bacterial expression system (pETI4b) within the E. coli BL2I(DE3)pLysS cell line. The expressed protein will be used to generate GRSPaV CP specific antibodies.
AFRIKAANSE OPSOMMING: Virusse is van die belangrikste patogene by wingerd. Daar bestaan geen effektiewe chemiese beheer nie, en geen wingerd- of ander natuurlike weerstandsgene teen wingerdvirusse is al ontdek nie. Die primêre metode van beheer t.o.v. wingerdvirusse is voorkoming deur biologiese indeksering, en molekulêre- en serologiese toetsing van onderstokke en entlote voor verspreiding. As gevolg van die verspreiding van wingerdvirusse deur insekvektore, en in die geval van GRSPa V die tekort aan serologiese toetsing, is dié metodes van virusbeheer nie altyd effektief nie. In die verlede is metodes soos kruis-beskerming en patogeen-afgeleide weerstand (PDR) gebruik om virusweerstand te induseer, maar met inkonsekwente resultate. In onlangse jare is post-transkripsionele geenonderdrukking (PTGS), 'n natuurlike plantbeskermingsmeganisme, met groot sukses toegepas om geteikende virusweerstand te induseer. Die Waterhouse-navorsingsgroep het planttransformasievektore ontwerp wat spesifieke virusweerstand induseer d.m.v. PTGS. Die vervaardiging van virus spesifieke tranformasievektore vir die indusering van wingerdvirusweerstand was die primêre doelwit van hierdie studie. Die Waterhouse-sisteem was gebruik vir die konstruksie van drie transformasievektore, met die pHannibal vektor as basis. Elke vektor bevat homoloë virus kapsiedproteïen (CP) geensegmente, gekloneer in 'n komplementêre vorm stroom-op en stroom-af van 'n intronvolgorde. Die primêre vektor (pHann-SAScon) bevat komplementêre CP geensegmente van beide GRSPaV en GLRaV-3, en was ontwerp vir die indusering van veelvoudige-virusweerstand. Die CP-geen van GRSPa V was vanuit RSP-geïnfekteerde wingerd geïsoleer, vir die konstruksie van die primêre vektor. 'n Kloon van die GLRa V-3 CP-geen was verkry. Die tweede vektor (pHann-LR3CPsas) bevat komplementêre CP geensegmente van GLRaV-3. Die derde vektor (pHann-LR2CPsas) bevat komplementêre CP geensegmente van GLRa V-2. Die kasset bestaande uit die komplementêre CP geensegmente van beide GRSPaV en GLRaV-3, was gekloneer in pART27 (pART27-HSAScon), en gebruik om N tabacum cv. Petit Havana (SRI) te transformeer d.m.v. A. tumefaciens bemiddelde transformasie. Ongelukkig het potensiële transformante nie geregenereer op bewortelingsmedia nie; gevolglik was geen molekulêre toetse gedoen om transformasie te bevestig nie. Na suksesvolle transformante gegenereer is, sal infeksie met 'n rekombinante-virusvektor (bestaande uit PYX, die GFP geen as waarneembare merker en die komplementêre CP geensegmente van beide GRSPa V en GLRa V-3) gebruik word om die effektiwiteit van die vektore as weerstandsinduseerders te toets. 'n Sekondêre doelwit is by die projek gevoeg toe 'n behoefte aan GRSPaV spesifieke teenliggame binne die Suid-Afrikaanse wynbedryf geïdentifiseer is, vir gebruik in serologiese toetsing. Om toekomstige serologiese toetsing van GRSPa V te bemiddel, was die CP-geen geïsoleer en in 'n bakteriële uitdrukkingsisteem (PETI4b) uitgedruk, in die E. coli BL21(DE3)pLysS sellyn. Die uitgedrukte proteïne sal gebruik word vir die vervaardiging van GRSPa V CP spesifieke antiliggame.
Raja, Priya. "Methylation of Geminivirus Genomes: Investigating its role as a host defense and evaluating its efficacy as a model to study chromatin methylation in plants". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274728228.
Pełny tekst źródłaCamargo, Roberto de Almeida. "RNAi para o controle de Tuta absoluta em tomateiro". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11151/tde-08042014-095355/.
Pełny tekst źródłaSince their discovery, the phenomenon of gene silencing by RNA ( RNAi ) has rapidly become a widely studied and used technique in the molecular biological field. One of these possible applications is in the entomology field, more specifically for the control of insect pests, as a high efficiency, specificity and with reduced environmental impact alternative. Through the generation of transgenic plants expressing dsRNA targeting essential insect genes, their ingestion by the insect and consequently the uptake of the silencing RNA, may result in specific gene silencing, resulting in a variety of phenotypes that can range from loss of appetite, infertility to death. In this context, this study aimed to prove the feasibility of this technique to control tomato leaf miner (Tuta absoluta) in tomatoes plant, a major crop worldwide and seriously attacked by this pest, with losses that can reach 100%. For the present work, orthologous genes from successfully cases of insect gene silence described in the literature, was selected together with highly expressed genes in the early larval stages of T. absoluta, chosen after the insect molecular characterization and used in feeding assays with dsRNAs molecules to targeted these genes. Also, genetic transformation of the \"Micro-Tom\" tomato cultivar with two of these genes (V-ATPase and Arginine kinase) was conducted for testing in an herbivore assay. With these two approaches was possible to get solid evidences of the feasibility of the RNAi technique to control this insect, evidenced by specific gene silencing observed and its consequent effect on pest phenotype.
Tsao, Theresa Tsun-Hui. "Towards the development of transgenic banana bunchy top virus (BBTV)-resistant banana plants : interference with replication". Queensland University of Technology, 2008. http://eprints.qut.edu.au/17031/.
Pełny tekst źródłaBoehm, Christian Reiner. "Gene expression control for synthetic patterning of bacterial populations and plants". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267842.
Pełny tekst źródłaRaponi, Mitch. "Antisense RNA-mediated gene silencing in fission yeast /". 2000. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20020131.041016/index.html.
Pełny tekst źródłaJordan, Chad Victor. "Geminivirus-induced gene silencing as a method to determine the role of essential cell cycle genes in plant development". 2005. http://www.lib.ncsu.edu/theses/available/etd-05182005-011034/unrestricted/etd.pdf.
Pełny tekst źródłaShittu, Hakeem Olalekan. "PLANT-ENDOPHYTE INTERPLAY PROTECTS TOMATO AGAINST A VIRULENT VERTICILLIUM DAHLIAE". Thesis, 2010. http://hdl.handle.net/10214/2271.
Pełny tekst źródłaCanadian Commonwealth Scholarship and Fellowship Plan
Shih, Jie-Ren, i 施傑仁. "Development of transgenic solanaceous plants resistant to multiple viruses via gene silencing". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/90081090820004973680.
Pełny tekst źródła國立中興大學
植物病理學系
90
Abstract The concept of pathogen-derived resistance (PDR) postulated by Sandford and Johnston states that plants transformed with genes from pathogen may confer resistance to homologous or related pathogens. Previous studies of Jan et al. had shown that N gene segments (400 bp) of Tomato spotted wilt virus (TSWV) fused with three shorter N gene segments (200 bp) of TSWV, Groundnut ringspot virus (GRSV), and Impatiens necrotic spot virus (INSV) can induce PTGS by developing resistance against TSWV, GRSV, and INSV in Nicotiana benthamiana plants. Based on these results, Jan et al. formulated a hypothesis stating that transforming plants with transgene constructs having gene segments of different viruses linked to a universal silencer DNA can produce multiple virus resistance. In this study, we transformed N gene segment of Watermelon silver mottle virus (WSMoV) fused with three shorter N gene segments of TSWV, GRSV, and INSV to N. benthamiana plants. The results showed that transgenic plants with this construction can confer resistance to these three tospoviruses. To generate multiple resistance among viruses belonging to different genus and to confirm the use of the genes other then CP gene, nearly 250 bp CP gene segments of Potato virus Y (PVY), Tomato mosaic virus (ToMV), Cucumber mosaic virus (CMV), and segment of ToMV replicase gene were fused with WSMoV N gene segment and transformed to N. benthamiana plants. The R0 resistant lines obtained were challenged with PVY and three lines have shown high level of resistance. The seedlings collected from these will be subjected to select multiple viral resistance progenies.
Coleman, Rory Tristan. "Making Memories: Modes and Mechanisms of Gene Silencing by the Polycomb Repressive Complexes in Drosophila". Thesis, 2017. https://doi.org/10.7916/D8CC159Q.
Pełny tekst źródłaCho, Yu-Hsiu, i 卓育秀. "Generation of transgenic plants expressing gene silencing suppressor HC-Pro and analyses of the effects of HC-Pro on gene expression using Bamboo mosaic virus-based vector". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/30132412519406268384.
Pełny tekst źródła國立中興大學
生物科技學研究所
96
One of the strategies to increase the expression of foreign gene in plants is to generate transgenic lines that express a replicating virus vector carrying a gene of interest. However, productivity in combination of transgenic and viral vector expression system could be greatly reduced by post-transcriptional gene silencing (PTGS). This limitation could be effectively overcome by crossing stably-transformed plants expressing the suppressor of PTGS with a stably-transformed line carrying a replicating virus vector. In this study, we have generated transgenic N. benthamiana lines expressing HC-Pro gene by Agrobacterium-mediated transformation. At meantime, we also construct P1/HC-Pro mutant by inserting three additional amino acid into P1 region. To investigate the effects of HC-Pro on gene expression using Bamboo mosaic virus-based vector (BaMV vector), N. benthamiana plants were co-infiltrated with Agrobacteria harboring the plasmid clones of wild-type or mutant P1/HC-Pro and BaMV (pKB), or BaMV vector carrying GFP (pKBG) or VP1 epitopes of Foot-and-mouth disease virus (pKBVP1). At 7 and 14 days post infiltration (d.p.i.), plants co-infiltrated with pBIN-P1/HC and pKB or pKBG or pKBVP1 showed higher accumulation of viral coat protein or foreign proteins in both infiltrated and systemic leaves than those without pBIN-P1/HC; but there were no significant difference between the infiltration with and without mutant P1/HC-Pro. P1/HC-Pro transgenic lines 37-5-9 and 37-5-11 were agroinfiltrated with pKB、pKBG or pKBVP1, the virus and foreign gene accumulation of infiltrated and systemic leaves were higher than non-transgenic line. Furthermore, symptom-less transgenic N. benthamiana line B2B12-1 expressing full length BaMV-S genome was agroinfiltrated with wild-type or mutant P1/HC-Pro, the virus accumulation of infiltrated leaves was higher than non-infiltrated one; but there was no significant difference between systemic leaves of the plants infiltrated either with wild-type or mutant P1/HC-Pro or without. We hypothesize that HC-Pro could suppress local and systemic gene silencing in plants and improved the replication of virus and the expression of foreign proteins, but in B2B12-1 line, P1/HC-Pro could just improve the virus accumulation in infiltrated leaves by suppressing local gene silencing.
Wu, Hui-Wen, i 吳惠雯. "Generation of transgenic plants conferring siRNA-mediated resistance against two potyviruses, and analysis of discriminating mutations of potyviral gene-silencing suppressor on pathogenicity and symptom development". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/40229438427144610046.
Pełny tekst źródła國立中興大學
植物病理學系所
97
Production of oriental melon (Cucumis melo L.) worldwide is often limited by infection by two potyviruses, the watermelon infecting Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus W type (PRSV W) and. In order to engineer melon lines resistant to these potyviruses, a construct containing the coat protein (CP) sequences of these viruses was generated and used to transform an elite cultivar of oriental melon (Silver light) mediated by Agrobacterium using an improved cotyledon-cutting method. Altogether, our results indicated that RNA-mediated post-transcriptional gene silencing (PTGS) was the underlying mechanism of virus resistance of the transgenic melon lines. In order to further understand the relationship between plant defense and virus counteraction, we investigated the role of gene silencing suppressor, potyviral HC-Pro, which affects small RNA pathways involving in pathogenicity and symptom development. This dissertation is divided into five (including appendix) chapters as described below. Chapter 1, “Literature review” describes references relevant to this study. Chapter 2, 3 and 4 comprise the main text of this thesis, describing the engineering of transgenic melon lines resistant to ZYMV and PRSV W (Chapter 2 and 3) to solve the potyvirus problem in the field. We used binary vector harboring single (ZYMV) or double (ZYMV and PRSV W) CP constructs to transform an elite cultivar of oriental melon (Silver light) mediated by Agrobacterium using an improved cotyledon-cutting method. Removal of 1 mm portion from the proximal end of cotyledon greatly increased the frequency of transgenic regenerants by significantly decreasing the incidence of false positive and aberrant transformants. Southern hybridization analysis of transgenic lines revealed random insertion of the transgene in host genome, with insert numbers differing among transformants. Northern hybridization analysis evidenced an inverse correlation of the levels of accumulation of transgene transcript to the degrees of virus resistance, indicating post-transcriptional gene silencing (PTGS)-mediated transgenic resistance. Chapter 4 describes “Discriminating mutations of HC-Pro of Zucchini yellow mosaic virus with differential effects on small RNA pathways involving viral pathogenicity and symptom development”. It is well known that the potyviral HC-Pro is a gene silencing suppressor. We sought to obtain molecular evidence on the roles of the three highly conserved amino acids, R180I (mutation A), F205L (B), and E396N (C) of HC-Pro in microRNA (miRNA) and small interfering RNA (siRNA) pathways related to viral pathogenicity and symptom development using transgenic Arabidopsis plants system. We demonstrated that amino acid residues 180, 205 and 396 of HC-Pro are critical in suppression of miRNA, trans-acting siRNA (ta-siRNA) and virus induced gene silencing (VIGS) pathways, but not sense-post transcriptional gene silencing (s-PTGS). Because the R180I/ E396N HC-Pro mutant does not interfere with miRNA and tasiRNA pathways the ZGAC mutant elicits only attenuated symptoms. Furthermore, the recovery seen on ZGAC-infected plants likely results from the weak VIGS suppression by the double AC mutations of HC-Pro. The findings of this study are useful to protect high levels of transgene expression and to genereate an attenuated potyvirus for control of virus by cross protection.. Chapter 5 (Appendix) entitled “Molecular evolution of a viral non-coding sequence under the selective pressure of amiRNA-mediated silencing” was carried out at Prof. Nam-Hai Chua’s laboratory, Rockefeller University, during my Ph.D program (2006-2008). The published paper is included as an appendix, because all the experiments of this project were carried out at Prof. Chua’s laboratory and this study was not directly connected to thesis. The main objective of this chaper was directed to determine, through artificial mutagnesis, the criticality of single nucleotide positions in the amiRNA-targeted sequence of 21 nucleotides, which were constructed in a potyvirual vector. Furthermore, the evolution of the virus through deletion and substitution in amiRNA-targrted sequence to escape amiRNA recognition was also investigated.
Tran, Van Tuan. "Adhesion of the rapeseed pathogen Verticillium longisporum to its host Brassica napus: Uncovering adhesion genes and the evolutionary origin of the fungus". Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-000D-F1D2-9.
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