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Ientification Of Up-regulated Genes In Tea Leaves Under Mild Infestation Of Ectrois Oblique

Posted on:2011-06-22Degree:MasterType:Thesis
Country:ChinaCandidate:J L QiaoFull Text:PDF
GTID:2143360305991926Subject:Botany
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Camellia sinensis is a kind of special economic crops, Ectropis oblique Prout is one of the main pests for Camellia sinensis. It sucks up juice of leaf by means of chewing as its source of nutrition,which jeopardizes the growth and developmemt of tea.To improve the comprehensive prevention from Ectropis oblique Prout, We need to study further response mechanism to pest damage in tea. As far as the research about plant hoppers feeding induction defense molecular mechanism, scientists mainly focus on some annual herbs such as arabidopsis, tobacco, corn and legume. These plants possess relatively simple ingredients and short cycle, however, tea is perennial woody plants, which have various metabolic pathway and complex ingredients, such as phenols, alkaloids, aromatic substances and saponins, Therefore, They have abundant resources of insect resistance. Domestic research of defense on tea pests mainly includes isolation and identification of inductive product, and its impact on natural enemies on the biochemical level. At present, the main components of identified compounds are indoles, terpenoids, alcohols and aldehydes, but the molecular mechanism of defense in pest has so far not been reported.We studied regulation of gene expression in resistance response to insect in 'Xinyang big leaf that belongs to Xinyangmaojian. the results are as follows:1. a subtracted cDNA library was constructed by means of suppression subtractive hybridization (SSH), using Ectropis oblique Prout-treated sample cDNA as tester and control sample cDNA as driver.2. The forward-subtracted cDNA was cloned, and the PCR products of 420 randomly selected clones were arrayed on the nylon membrane for screening. In 3 separate and independent experiments,28 cDNA clones were identified. According to real-time PCR analysis,19 cDNAs were verified by induction of Ectropis oblique Prout feeding, including lipid metabolism related gene, coding cell wall protein gene, lignin synthesis gene, flavonoids anabolic gene and transcription factor etc. Isolation of 13-lipoxygenase (13-LOX) gene andω-3 fatty acid desaturase gene shows that JA is an important signal molecule of insect resistance reaction. Many genes in tea flavonoid biosynthesis expression is induced by Ectropis oblique Prout feeding,this indicates flavonoids-like, especially condensed tannins, is an important part of defense system in tea.Plant cell wall is the first barrier against adverse environment, Ectropis oblique Prout feeding, the cell wall protein gene and lignin biosynthesis gene expression levels increased,so these genes play an important role in mandibulate insect feeding.3.5'and 3'RACE resulted in a 1293 bp cDNA clone consisting of a 15 bp 5'UTR and a 263 bp 3'UTR, and a 1014 bp ORF. The ORF encodes a polypeptide of 337 amino acids. Protein sequence alignment shows this protein has an C-terminal BURP domain. Database analysis using BLASTP revealed that the deduced amino acid sequence has high homology to protein contained BURP domain.Signal peptide analysis shows that the protein is secreted protein, the first 21 amino acids is the signal peptide region.
Keywords/Search Tags:camellia sinensis, ectropis oblique, gene cloning, rd22, sequence analysis
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