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Wild Strawberry: An emerging model for ecological and evolutionary genomics
Aaron ListonDept. of Botany & Plant Pathology
Oregon State University
Why Strawberry?
Campos-de Quiroz 2002. Plant genomics: an
overview. Biological Research 35:385-399.
1. Small Genome Size
Fragaria vesca 236-244 Mbp
Arabidopsis thaliana 153-166 Mbp
1. Small Genome Size2. Easily Grown and Cloned
Why Strawberry?
Fragaria moupinensis in Sichuan, China
1. Small Genome Size2. Easily Grown and Cloned3. Short Generation Time & Stature
Why Strawberry?
1. Small Genome Size2. Easily Grown and Cloned3. Short Generation Time & Stature4. Efficient Creation of Transgenic Plants
Pantazis et al. 2013. Development of an efficient transformation method by Agrobacterium
tumefaciens and high throughput spray assay to identify transgenic plants for woodland
strawberry (Fragaria vesca) using NPTII selection. Plant Cell Reports 32: 329-337.
Why Strawberry?
1. Small Genome Size2. Easily Grown and Cloned3. Short Generation Time & Stature4. Efficient Creation of Transgenic Plants5. Unique Fruit Development
Why Strawberry?
1. Small Genome Size2. Easily Grown and Cloned3. Short Generation Time & Stature4. Efficient Creation of Transgenic Plants5. Unique Fruit Development6. Related to an Edible, High-Value Crop
Why Strawberry?
Cultivated Strawberry is an
Octoploid
Why Strawberry is a Bad Idea
Drawing by Pierre Dénys de Montfort (1801)
Bo & Davis. 2011. Conservation and loss of ribosomal RNA gene sites in diploid and polyploid Fragaria (Rosaceae). BMC Plant Biology 11: 157.
Fluorescence in situ hybridization (FISH) with 5S (green) and 25S (red) rDNA probes.
Fragaria vesca 2n=14
Fragaria virginiana 2n=56
Cultivated Strawberry is an
Octoploid
30% of 100 bp reads did
not distinguish between the
two progenitor genomes of
cultivated cotton.
“Using an arbitrary length of 1000
bp, we found 47,399 unique loci
where sequence reads of the AT-
genome and DT-genome were
indistinguishable when compared to
each other and to the reference
genome. Assuming sequence read
lengths <500bp, these regions would
likely co-assemble during a de novo
whole genome shotgun assembly
with current read lengths.”
Page et al. 2013.
G3. Early Online.
454, SOLiD and Illumina genome & transcriptome
39X coverage, 25-365 bp reads
202 million base pair (Mbp) assembly
3263 scaffolds 34,809 predicted genes
Fragaria vesca ssp. vesca “Hawaii 4”
“Any sequenced genome is simply a parts list. It is a comprehensive accounting of the
components that make up the genetic basis of the organism and the elements that control
their expression and activity”.
“Any sequenced genome is simply a parts list. It is a comprehensive accounting of the
components that make up the genetic basis of the organism and the elements that control
their expression and activity”.
“Any sequenced genome is simply a parts list. It is a comprehensive accounting of the
components that make up the genetic basis of the organism and the elements that control
their expression and activity”.
“The strawberry plant may be thought of as a factory that takes
water, sunlight, carbon dioxide, and a pinch of minerals to
assemble a desirable product. If you want to understand the
product and how to make it better, cheaper, or faster, you need to
understand the mechanics of the factory at a nuts-and-bolts level.
This level of understanding comes quite quickly if you have the
blueprints. Blueprints show you how parts are assembled and
interact. Unfortunately, blueprint-level resolution of the strawberry
is still decades in the future”.
“Any sequenced genome is simply a parts list. It is a comprehensive accounting of the
components that make up the genetic basis of the organism and the elements that control
their expression and activity”.
“The strawberry plant may be thought of as a factory that takes
water, sunlight, carbon dioxide, and a pinch of minerals to
assemble a desirable product. If you want to understand the
product and how to make it better, cheaper, or faster, you need to
understand the mechanics of the factory at a nuts-and-bolts level.
This level of understanding comes quite quickly if you have the
blueprints. Blueprints show you how parts are assembled and
interact. Unfortunately, blueprint-level resolution of the strawberry
is still decades in the future”.
“Any sequenced genome is simply a parts list. It is a comprehensive accounting of the
components that make up the genetic basis of the organism and the elements that control
their expression and activity”.
“The strawberry plant may be thought of as a factory that takes
water, sunlight, carbon dioxide, and a pinch of minerals to
assemble a desirable product. If you want to understand the
product and how to make it better, cheaper, or faster, you need to
understand the mechanics of the factory at a nuts-and-bolts level.
This level of understanding comes quite quickly if you have the
blueprints. Blueprints show you how parts are assembled and
interact. Unfortunately, blueprint-level resolution of the strawberry
is still decades in the future”.
Reference guided assembly De novo assembly
Genome Assembly
Genome Coverage
Low Coverage High Coverage
Targeted sequence capture approach
Cronn et al. 2012 Amer J Bot
Solution Phase Hybridization(e.g., Mycroarray MyBait)
• ‘Baits’ synthesized on arrays
• 80-120 bp RNA probes
• Hybridization in solution
• 100 – 500 ng DNA of input library
• Immobilization via biotin-streptavidin bead capture
Targeted sequence capture advantages
• Ability to target SNPs known to be informative in parents
• Efficient data generation-1000s of markers in multiple individuals
• Low variation in locus recovery
• Rapid means for comparative analysis between related species
Cronn et al. 2012 Amer J Bot
vescaiinumae nilgerrensis pentaphyllanipponica viridis
Fragaria Morphological “Diversity”
Leaf and flower Images courtesy of USDA National Clonal Germplasm Repository.
Variation in Sexual Systems
female hermaphrodite
Fragaria vesca subsp. bracteata
Fragaria virginiana
gynodioecious
dioecious
Genetic Linkage Mapping of Male Sterility
female hermaphrodite
Fragaria vesca ssp. bracteata
Genetic Linkage Mapping
www.lifesciencesfoundation.org
Targeted sequence linkage mapping in Fragaria vesca ssp. bracteata
Maternal genome 5.4x
coverage
Paternal genome 3.2x
coverage
Probes targeting 6575 informative variants
48 F1
offspring
~2Mb
sequenced in
each offspring
Mybaits:
3 overlaping
100bp
Sum of all baits
=1% genome
Mean read
depth = 120x
Tennessen et al. 2013
Log 1
0o
f o
dd
s (L
OD
) t
hat
lin
kage
did
no
t o
ccu
r b
y ch
ance
Linkage Groupaxis = recombination events
Linkage between markers on chromosome 4 and male sterility (40 flowering progeny)
Tennessen et al. 2013
Tennessen et al. 2013
Identification of a 2.4 Mbp gap in the assembly
Fine Mapping to a 338 kb locus (95 progeny)
Tennessen et al. 2013
57 Candidate Genes
Tennessen et al. 2013
Chromosomal Rearrangements
or Assembly Artifacts?
Tennessen et al. 2013
SNP detection:
diploid vs octoploid
Polymorphism in the octoploids
Avg. read depth 120x
1:1 1:7
2 adjacent SNPs
that satisfy criteria
Read depth
>32x
Octoploid Linkage Map
Octoploid Linkage Map
Tennessen et al.
Fragaria chiloensis
Fragaria virginiana
Fragaria ananassa1759Philip MillerGardener’s Dictionary
Origin of the Cultivated Strawberry
Introduced to Europe in 1714
Introduced to Europe by 1629
F. virginiana
F. chiloensis F. ananassa var. cuneifolia
Acknowledgements
Rich Cronn – US Forest Service PNW Research Station
Tia-Lynn Ashman – University of Pittsburg
Laboratory & Bioinformatics:
Matt Parks – Griffith Univ, Brisbane Shannon Straub – Oregon State U.Jacob Tennessen – Oregon State U.Brian Knaus – USDA ARSRajanikanth Govindarajulu – U. PittsburghKevin Weitemier – Oregon State U.Chris Edwards – Oregon State U.Zach Foster – Oregon State U.Kimberly Hansen – Northern Ariz U. Laura Mealy – South Dakota State U.
OSU Center for Genome Research & Biocomputing:
Mark DasenkoChris SullivanMathew Peterson
Plants:
Katherine Schuller – U. Pittsburgh
John Syring – Linfield College
USDA NCGR
Nahla Bassil
April Nyberg
Kim Hummer
Funding:
US National Science Foundation
Zach Foster
Kevin Weitemier
Laura Mealy
Kimberly Hansen
Stephen Meyers
Matt Parks
Shannon Straub
Jacob Tennessen
Rich Cronn
Tia-Lynn Ashman
Chris Edwards
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