Lecture 12 - Arabidopsis as a model system - Gray Flashcards
What are some examples of model systems in plants?
Tomato - fleshy fruit development, disease resistance Barley - good genetic resources Pea - Mendel Snapdragon - developmental genetics Maize Petunia
What are the problems with these systems?
Big plants
Complex genomes
We want something with a smaller genome
Why was maize important for genetics?
First plant to have genetic map - we discovered lots from it.
Eg carotenoid biosynthesis, bioethanol, transposons.
What was petunia used for?
Discovery of RNAi - attempts to overexpress chalcone synthase gene (CHS) led to silencing and thus loss of colour (anthocyanin biosynthesis)
Also used for studying petal formation, shoot branching, transposons.
What is Arabidopsis thaliana?
Small weed that grows in temperate climates. Tiny plant. Small genome. Diploid - many of our crops are polyploid and complex. Good model organism.
What were some obvious beneficial traits of Arab?
Small Simple to grow Self-fertilising Diploid 20,000 progeny from single plant Short life cycle - approx 8 weeks Many polymorphisms between accessions
What were some fortuitous traits?
Easily transformed - agro mediated. This can be biolistic or by dipping.
Small genome 135mb vs human 3000mb
Are there many mutants?
Yes, lots of mutants for each gene. Open and sharing community.
What has Arab done for science?
Genome-wide T-DNA collections. When T-DNA enters a genome it can create mutants (by disrupting genome). So they developed T-DNA as an insertion tool to try to saturate the genome. You can then do reverse PCR to find out where it has gone in.
