Biotechnology Flashcards
Genzentren
Ursprungszentrum landwirtschaftlicher Nutzpflanzen
F1 hybrids
grow larger/better than parent plants
if seeds collected: offspring will loose these traits
Genetic modification techniques
Cross breeding
Mutagenesis
Polyploidy
Protoplast Fusion
Transgenesis
Genome Editing
First four are seen as breeding => not regulated
Why is cross breeding so time consuming?
You have to make crosses and backcross them with parents
What do all genetic modification methods have in common?
Create genetic diversity that can then be selected for
GE vs GMO
GMO common term to describe what scientists call GE, but not biologically correct, means biotechnologically changed organisms whereas biologically the term includes breeding, as these techniques also modify a genome
Methods of nucleic acid delivery
Particle bombardment, Agrobacterium, Nanoparticle, Virus
Agrobacterium tumefaciens
Causes crown gall disease
Methods to transform plant cells with Agrobacterium
Transient expression via infiltration (can be used for vaccine production?)
Dip-inoculation => flowering plants => select germinated seeds
Co-incubation with plant tissues => selection => cell culture using cyt/aux
Precise genome editing techniques
ZNFs, TALENS, CRISPR-Cas9
TALENS
Transcription activator-like effector nucleases
Xanthomonas TAL type-III effectors
Inject virulence factors by type-III secretion systems
=> induce gene expression by binding to promotor
Hypervariable residues that can bind to DNA bases
DNA-binding proteins with predictable specificity
Structure wraps around DNA
CRISPR-Cas9
Guide RNA, CAS9 protease?
Applications of genetic engineering
Improved resistance to pathogens and pests
Resistance to drought and abiotic stress
Improved yields
Increased nutritional value
Reduced allergens and toxins
De-novo domestication
Improving nitrogen fixation
Introduce genes for Symbiosis with Nitrogen fixating bacteria into non-legume plants (many genes involved => complex)
Provide plants with genes for nitrogen fixation directly
Photosynthesis efficacy
The C4 Rice Project
Deregulate processes that are inefficient/produce toxic elements
Golden Rice
Engineer rice to produce Vitamin A
Resistance => didn’t proceed for a long time
Tomato fruit manipulation
De-novo domestication
Size:
Mutate promotor of genes involved in development
=> create diadic pattern of expression
=> some genes more, some less expressed in certain plant lines
=> see impact of modulating these genes
More, smaller tomatoes on branching, bushy plants
Increase of plant disease outbreaks bc of
Increased global trade
Pathogen host-jumps
Climate change
Control of plant diseases
Chemicals
Classical breeding
Genetic engineering
But others?!
GE to control plant diseases
Gene silencing
Genome-editing of susceptibility gene
Transfer and pyramiding of immune receptors
Rainbow Papaya
Many transgenic
Virus (PRSV) spread on Hawaii
=> small RNA production in response to virus (antisense strand that silences replication of virus)
=> ‘immunize’ plant against virus by introducing PRSV coat protein into virus
small RNAs
can be produced by plant in response to pathogen => export into pathogen by extracellular vessicles => try to silence virulence genes
HIGS: host induced gene silencing
SIGS: spray induced gene silencing
Not often reproduced technique up until no
Mutations in suceptibility
Mlo-knock out mutants
Mlo is conserved negative regulator of plant immunity => in all plants
7 transmembrane domain (Ca2+ ion channel?)
Selected for mutation by breeders => chemically induced mutation => now GE
Resistance to bacterial blithe in rice
Xanthomonas oryzae
Secrete TAL effectors that induce expression of SWEET sucrose transporters => susceptibility genes (sugar in apoplast enables bacteria to multiply)
=> deletion of part of promotor, so that bacterial effector cannot bind anymore
TAL effectors
Types of PRRs
Receptor kinases and
Receptor-like proteins
Way of perception is the same, but receptor-like proteins need additional protein with kinase domain for signal transduction
Most abundant protein in bacterial cells
EF-Tu
Widely conserved
But eIF18 perception restricted to brassicaceae => transgenic plants with resistance to bacteria
Diff in resulting immunity due to NLRs vs PRRs
PRRs (extracellular) => gradient in immunity
NLRs (mostly intracellular) => infection or no infection
Wheat Pm3 alleles
confer resistance to powdery mildew
combinations
Atypical R genes
Genes that confer immunity but don’t encode immune receptors
Mechanism of disease resistance is unknown
ABA production
Production of small signaling peptide in roots, transport to leaves perception by receptors leads to ABA translation/accumulation
