Presentation Detail

Ecological Genetics and/or Genomics

Yuan, Wei [1], Purugganan, Michael [1].

The genetic architecture of seed germination speed variation in Arabidopsis thaliana.

Germination timing of seeds is a trait of fundamental importance to plant life history and adaptation. It is sensitive to environmental cues and determines the condition and hence the type and intensity of natural selection that a plant encounters throughout the rest of its life cycle. Germination speed captures the sensitivity of non-dormant seeds to germination cues, and exhibits strong correlation with plant̢۪s fitness under competition and ephemerally clement weather. Thus, understanding its genetic basis is imperative to elucidate early responses of plants to permissive environments. Germination speed displays quantitative variation in nature, but the genetic basis of its variation is largely unexplored. This is partly due to the lack of detection power of traditional QTL mapping methods whose resolution is limited by the number of recombination events. Here we implemented the novel yeast Extreme-QTL (X-QTL) mapping technique (Ehrenreich et al, 2010) in A. thaliana. Using population-based phenotyping and high-throughput bulk segregant genotyping, the rapid germination trait was mapped under both regular and extreme saline conditions. By screening replicates of 100,000 segregating seeds from an advanced-generation bi-parental cross, 14 X-QTLs for rapid germination under normal conditions and 37 X-QTLs under extreme saline conditions were detected. Based on simulated and experimental data, 150-kb flanking genomic sequences on both sides of the X-QTL peak positions were annotated and candidate genes identified. Various promising candidate genes are located within close proximity to the mapped X-QTL peaks. Our results suggest that rapid germination is a genetically complex trait, and has strong gene-by-environment interactions. Both parents contain strong alleles for rapid germination under different environmental treatments. Our project establishes the basic protocols of X-QTL mapping in a multicellular eukaryotic organism, and demonstrates that X-QTL mapping has great potential in discovering minor effect QTLs (less than 3% variation explained) for selectable seed traits in A. thaliana.

1 - New York University, Department of Biology-Center for Genomics and Systems Biology, 12 Waverly Pl 8th Fl, New York, NY, 10003, USA

Keywords:
germination
Seed trait
life history QTL
ecological genomics
evolutionary genomics.

Presentation Type: Regular Oral Presentation
Session: 38
Location: Cotton C/Snowbird Center
Date: Saturday, June 22nd, 2013
Time: 4:15 PM
Number: 38004
Abstract ID:714
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation,Student Travel Awards from the ASN