Transcript brittany restoration

Pollen viability across a landscape:
geographic variation in the
cost of male-fertility restoration
in gynodioecious Lobelia siphilitica
Maia Bailey, Providence College
Andrea Case, Kent State University
Christina Caruso, University of Guelph
Plant breeding systems
hermaphrodity
dioecy
gynodioecy
Cytoplasmic ‘disease’ & nuclear ‘cure’
• Selfish cytoplasmic alleles prevent pollen
(cytoplasmic male sterility, CMS)
• Nuclear alleles ‘resist’ CMS (restorers of male
fertility, Rf)
• Like resistance genes in pathology, Rf can have
a ‘cost’ depending on context (cost of
restoration)
Latitude & females
Why be female?
• Selection
– On sexes directly
– On ‘resistance’ alleles
• Stochasticity
– Genetic drift
– Colonization/extinction
– Migration
– Etc.
McCauley & Bailey 2009
Lobelia siphilitica
Female hotspot
Evidence of stochasticity?
Caruso & Case 2007
Evidence of selection?
Caruso & Case JEB 2007 Fig 3
Currency of cost in L. siphilitica
Max cost of restoration varies
rs = 0.076
P = 0.003
CAR
ELK
R
TOE
K
CERA
WR
Larger populations w/fewer females
Case & Caruso New Phytol 2010
CMS/rf alleles match in populations
Within population crosses
Among population crosses
Sex ratio and genetic distance
GxE
Southern and northern genotypes under
northern conditions
Southern and northern genotypes under
southern conditions
Conclusions
• Female hotspot in Lobelia siphilitica has many
causes including both genetic drift and selection
• Populations vary for maximum possible cost of
restoration
• Restorer alleles more likely to match cytoplasmic
background in within population crosses than in
among population crosses
• The possibility that gene by environment
interactions contribute to hotspot is under
investigation
Acknowlegements
• Pollen counting
– Sarah Buttermore
– Kelsey Thetonia
– Erin Pratt
– Brittany Isabelle
– Jack Sporer
• Funding
– NSF ROA
– NSF EPSCoR