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SUMMARY:Haploid Arabidopsis thaliana: power tools for plant genetics - Pro
 f Simon Chan (University of California\, Davis)
DTSTART:20111010T100000Z
DTEND:20111010T110000Z
UID:TALK33567@talks.cam.ac.uk
CONTACT:Dr Beatrix Schlarb-Ridley
DESCRIPTION:Creating true-breeding homozygotes (e.g. recombinant inbred li
 nes or RILs) from a heterozygous F1 typically involves many generations of
  inbreeding. To accelerate this process\, plant breeders produce haploid p
 lants from a heterozygous parent\, then convert them into fertile diploids
  that are homozygous for every locus in the genome. Arabidopsis thaliana h
 aploids can now be made through a simple genetic cross. When a cenh3 GFP -
 tailswap mutant with altered centromeres is crossed to wild type\, mutant 
 chromosomes are lost after fertilization. Up to 50% of viable progeny are 
 haploids produced by complete genome elimination\, and we have introduced 
 dominant markers into cenh3 GFP -tailswap to facilitate their selection. H
 aploid Arabidopsis plants convert into fertile diploids spontaneously. Eac
 h haploid yields >50 fertile diploid seeds through random chromosome segre
 gation during meiosis. Haploid genetics has many applications: 1) New RIL 
 sets can be made in only two generations. 2) Multiple mutant construction:
  it is feasible to homozygose 8 unlinked mutations in a single generation.
  3) Gametophyte lethal mutations can be studied in a haploid plant. 4) Any
  nuclear genome can be combined with the cytoplasmic genomes of choice. 5)
  Tetraploid Arabidopsis can be converted into diploids to facilitate genet
 ic manipulations. Lastly\, we are using the principle of centromere-mediat
 ed genome elimination to engineer clonal reproduction (synthetic apomixis)
  in Arabidopsis. Crossing a mutant with diploid gametes (spo11 rec8 osd1\,
  or MiMe) to a mutant with altered centromeres yielded up to 34% clonal pr
 ogeny with the same heterozygous genotype as their MiMe parent. Thus\, clo
 nal reproduction in an Arabidopsis cross can be created by manipulating fo
 ur conserved genes. This result raises hope that apomixis can eventually b
 e engineered in crops\, allowing vigorous hybrids to be propagated through
  seed.
LOCATION:Large Lecture Theatre\, Department of Plant Sciences
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