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《植物基因工程》ppt课件

花匠小妙招
2024-11-13 01:49

【正文】 ce tags (FSTs) analysis showed no obvious site preference for integration throughout the genome. • About 40% of the integrations are in genes and more of them are in introns. Nonhomologous endjoining (NHEJ) occurs during TDNA integration • The mechanism of NHEJ makes deletions after TDNA integration a mon phenomenon. Events of NHEJ in AgrobacteriumTDNA integration • Integration is initiated by the 3’(LB) of the TDNA invading a poly Trich site of the host DNA • A duplex is formed between the upstream region of the 3’end of TDNA and the top strand of the host DNA. • The 3’end of TDNA is ligated to the host DNA after a region downstream of the duplex is degraded. Events of NHEJ in AgrobacteriumTDNA integration • A nick in the upper host DNA strand is created downstream of the duplex and used to initiate the synthesis of the plementary strand of the invading TDNA. Events of NHEJ in AgrobacteriumTDNA integration • The right end of the TDNA is ligated to the bottom strand of the host DNA. This pairing frequently involves a G and another nucleotide upstream of it. Plant genes involved in transformation • Mutant screen, 2hybrid screens and other methods have revealed a number of plant genes that are involved in transformation. • Rat mutants (resistant to Agrobacterium transformation), VIP genes and other genes were isolated. Plant Expression Vector Mono Vector System Two ponent Vector system • Genes = the coding system for instructions • A gene = is a segment of DNA Guanine (G) Cytosine (C) Adenine (A) Thymine (T) bases DNA DNA and Genes gene Genes and Proteins Gene (a piece of DNA) trait protein translation mRNA transcription Restriction enzymes As biological scissors “Gene Gun” Technique DNA coated golden particles Gene gun Cell division A plant cell with the new gene Transgenic plant Plant cell Cell’s DNA Duracell DNA containing the gene of interest Plant cell Protoplast Electroporation Technique Power supply DNA inside the plant cell The plant cell with the new gene Plant Expression Vector Mono Vector System Two ponent Vector system • Genes = the coding system for instructions • A gene = is a segment of DNA Guanine (G) Cytosine (C) Adenine (A) Thymine (T) bases DNA DNA and Genes gene Restriction enzymes As biological scissors Next Generation of Transgenic Crops • Plantbased vaccines • Enhanced nutritional content • Functional foods and phytoceuticals • Transgenic plants for phytoremediation • Plantderived plastics and polymers Where is the technology being used? • Valuedadded food? • In 1999 approximately 70% of foodstuffs in North America contain ponents derived from GM crops Why Should I Support the Biotech Industry? • By geically modifying plants we can: – Reduce pesticide use – Conserve fuel and water – Preserve nonpest insect populations – Increase food production per hectare of farmland – Enable crops to grow in suboptimal conditions – Increase the nutritional value of food Current Products • Transgenic Soybean – Roundup Ready • Resistant to Roundup Herbicide • Reduces the amount of herbicide applied to crops – Altered Fattyacid content • Changes the nutritional value Field after one round of application of Roundup herbicide Current Products • Canola – Herbicide resistant • Better for the environment – Altered fattyacid position • A valueadded food Current Products • Tomato – Flavr Savr Tomato • Delayed softening • Consumers get a better tasting tomato • Failed – Virus resistant tomato • Resistant to pests • Decreases the amount of pesticide applied to crops Transgenic tomato plants show resistance (left) while nontransformed plants are susceptible to cucumber mosaic virus under field conditions (right) Current Products • Corn – Bt Corn The Monarch Butterfly debate: – A microbial gene added results in the crop being resistant to insects – Does it impact the Monarch Butterfly? 187。 cyt, cytokinin synthesis) and the production of low molecular weight amino acid and sugar phosphate derivatives called opines (ocs, octopine(章鱼碱 )。Plant geic engineering Zichao Mao Yunnan Agricultural University Motivation What is geic engineering? Why do scientists geically engineer anisms?  Introduction of genes from one species of anism into anism of a different species (transgenic anism) • Cloning a gene to determine its function • Change the phenotype of an anism to improve a desired trait  Traditional geic manipulation • Selective breeding to improve nutritional value of plants  too slow  Geic engineering by molecular techniques • Allows to create larger geic changes at a much more rapid pace • Production of large amounts of pharmaceuticals Geic engineering in plants Agrobacterium tumefaciens causes crown gall disease Ti plasmid T