Passato, Stefania (2016) RNAi and functional characterization of genes involved in plant-insect tritrophic-interactions. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Resource language: English
Title: RNAi and functional characterization of genes involved in plant-insect tritrophic-interactions
Date: 31 March 2016
Number of Pages: 111
Institution: Università degli Studi di Napoli Federico II
Department: Scienze Chimiche
Scuola di dottorato: Biotecnologie
Dottorato: Scienze biotecnologiche
Ciclo di dottorato: 28
Coordinatore del Corso di dottorato:
Date: 31 March 2016
Number of Pages: 111
Keywords: NIMIN genes; NPR1 gene; 102 gene; RNAi; Solanum lycopersicum; plant genetic transformation; Bimolecular Fluorescence Complementation; BiFC.
Settori scientifico-disciplinari del MIUR: Area 07 - Scienze agrarie e veterinarie > AGR/07 - Genetica agraria
Area 05 - Scienze biologiche > BIO/10 - Biochimica
Area 05 - Scienze biologiche > BIO/11 - Biologia molecolare
Area 05 - Scienze biologiche > BIO/13 - Biologia applicata
Area 05 - Scienze biologiche > BIO/18 - Genetica
Date Deposited: 13 Apr 2016 08:40
Last Modified: 22 Apr 2017 01:00

Collection description

The study of plant defence mechanisms can lead to the discovery of new strategies for crop protection against insects. To this aim, the first step is the characterization of the genes that are involved in plant defence mechanisms. Aphids are among the most damaging pests in temperate climates. These insects evolved the ability to establish a prolonged feeding site on plant tissues, most likely because of their predicted ability to deceive plant defence mechanisms. A recent transcriptomic study indicated that tomato (Solanum lycopersicum) has a dynamic transcriptional response following Macrosiphum euphorbiae attack. In that study, a probe annotated as NIMIN 2C, was among the genes with the higher level of expression. In Arabidopsis NIMIN genes are able to negatively regulate distinct functions of NPR1, a crucial player in the pathway cross talk between jasmonic (JA) and salicylic acid (SA). Therefore, the functional characterization of tomato NIMIN 2C genes aims to identify essential modulators of plant resistance, ultimately paving the way for the development of new breeding targets and control strategies. To achieve this goal, expression levels of NIMIM genes in Arabidopsis and tomato plants were studied in different conditions using wet and dry-lab experiments. To check the interaction in tomatoes among NIMIN 2C and NPR1 genes, Bimolecular Fluorescence Complementation (BiFC) analysis were performed. Transgenic plants were also produced for the interference RNA-mediated suppression of these genes. Interference (RNAi) is an epigenetic mechanism that has been shown to reduce gene expression of a vast range of living organisms. It is a powerful tool for functional analysis of genes involved in plant defence against biotic stress. This goal is usually achieved by either the ectopic production or the introduction of double stranded RNA molecules (dsRNA), in order to phenocopy the loss of function of specific target genes. RNAi can be also used to suppress genes essential for pest development, survival, or parasitism by producing in planta appropriate dsRNA. Recently, a gene involved in insect immune response (named 102) has been isolated and characterized in a phytopaghous lepidoptera. Preliminary available data indicate that RNAi-mediated silencing of the 102 gene generate a lethal phenotype during embryonic development and, at larval stages, immunosuppression and an increase in susceptibility to stress. Toxoneuron nigriceps is a parasitoid of larvae of different species. During oviposition, the parasitoid injects a polydnavirus into the host together with eggs. This polydnavirus is responsible for the suppression of the host immune system. A non-coding RNA (rc5’ntTnBV) coded by the polydnavirus was isolated from parasitized larvae. This RNA has a region complementary to the untranslated 5 ' region of 102 gene. For this reason the 102 represents a suitable target gene to be suppressed producing dsRNAs to indirectly increase plant resistance to specific lepidoptera.


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