Transcript Capsicum

Capsicum
Phylogeny and Domestication
Brian Walsh
Family:
Subfamily:
Tribe:
Solanaceae
Solanoideae
Capsicinae (since 1999)
•Estimated 25 species (my count =37)
•Native to South and Central America
•Current distribution is global
•One of the most utilized spice in the world
•Part of human diet for 9000 years
•All diploid
•Typically self-fertilize
•Most n=12 (some n=13)
One of the most diversely utilized plants
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Spice
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Food
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Dye
Medicine
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Weapons
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Poison
Drinks
Deterrent
Insecticide/Pesticide
Preservative
Snuff
Rituals
Tribute
Town Names
Punishment
Domestication
•Davenport (1970) proposes all five domesticated species arose from a
single ancestor (C. frutescens L.) (Lumper) (based on morphology)
•Heiser (1971) proposes each domesticated species arose from its own
unique wild ancestor (Splitter) (hybridization studies)
Pickersgill (1972) agrees with Heiser - different cultivated species show a
combination of characters suggesting domestication by different groups of
people living in different areas.
•Eshbaugh (1983) argues at least three distinct domesticated lineages
based on morphology, plant breeding and enzyme analysis
(C.
chacoense is plesiomorphic)
Agricultural Centers of the New World and the theoretical flow of speciation
View from 1000000 km above 5°18’S 63°55’W
Based on C. chacoense
Domesticated Characters in
Capsicum
Domesticated
• Gigantism of fruit
• Altered fruit shape
• Fruit color other
than red
• Retained on
peduncle a maturity
• Variable capsaicin
levels
Wild
• small fruit
• Fruit round
• Red fruit
• Peduncle dehiscence
at maturity
• High capsaicin levels
Capsicum annuum
Eshbaugh’s breakdown into flower color categories (why?)
Capsicum annuum complex
C. annuum var. annuum
C. annuum var. avicular
C. frutescens
white flowers
C. chinense
C. chacoense
Capsicum baccatum group
C. baccatum var. praetermissum
C. baccatum var. pendulum
C. baccatum var. baccatum
white flowers
with yellow spots
Capsicum eximium complex
C. pubescens
C. eximium
C. cardenasii
Total species=8
purple flowers
C. frutescens
Tabasco
C. baccatum var. praetermissum
Capsicum eximium
Capsicum eximium
C. baccatum var. praetermissum
Capsicum
cardenasii
Only species that
strictly outcrosses
Flower color classification of
Capsicum
•Color categories inaccurate (too many exceptions)
•Only a fraction of total species included
•Doesn’t agree with molecular data
Current phylogenetic questions
• Monophyly of genus
• Resolving species relationships
Capsicum Monophyletic?
Modified from Bohs & Olmstead 1997
A
B
C
A
B
C
A
A
C
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Monophyletic
A
A
C
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Not Monophyletic
Walsh 2001
(chloroplast atpB-rbcL spacer data)
Walsh 2001
(chloroplast atpB-rbcL spacer data)
Walsh 2001
combined atpB-rbcL spacer and waxy data
n=12/13
Walsh 2001
(chloroplast atpB-rbcL spacer data)
Capsicum monophyly
• Intact for the time being
• Odd C. ciliatum seems to be the weak link
(n=13)
Mascone’s missing tree
Mascone 2003
Flow cytometry and Feulgen densitometry
1C-value of DNA = an equation for calculating
genome size in absolute units
Genome size in Mbp
Visualization of Mascone’s results
Capsicum anuum complex
C. annuum var. annuum
C. annuum var. avicular
C. frutescens
white flowers
C. chinense
C. chacoense
United by similar DNA amount and little heterochromatin
1C
G
C. chacoense
3.35
3273
C. annuum var. annuum
3.38
3312
C. frutescens
3.40
3332
C. chinense
3.42
3352
Capsicum baccatum group
C. baccatum var. praetermissum
C. baccatum var. pendulum
C. baccatum var. baccatum
C. baccatum var. umbilicatum
white flowers
with yellow spots
New variety described in 1998
Domesticated status unknown
Similar DNA amounts – not surprising
1C
G
C. chacoense
3.35
3273
C. annuum var. annuum
3.38
3312
C. frutescens
3.40
3332
C. chinense
3.42
3352
C. baccatum var. pendulum
3.69
3621
C. baccatum var. baccatum
3.71
3636
C. baccatum var. umbilicatum 3.76
3636
Interpreted from data – not explicitly stated
Capsicum eximium complex
C. pubescens
C. eximium
purple flowers
C. cardenasii
C. parvifolium synonym with C. cardenasii? (but description is off – tree?)
C. parvifolium only compared to C. campylopodium
points out distantly related and nothing more
C. campylopodium groups with C. pubescens – large genome size, and large
amounts of heterochromatin forming complex patterns (tone implies trepidation)
C. eximium has DNA content intermediate between C. baccatum and C. pubescens,
but genome size supports close relationship to C. pubescens as well as isozyme and
cross studies
1C
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G
C. chacoense
3.35
3273
C. annuum var. annuum
3.38
3312
C. frutescens
3.40
3332
C. chinense
3.42
3352
C. baccatum var. pendulum
3.69
3621
C. baccatum var. baccatum
3.71
3636
C. baccatum var. umbilicatum 3.76
3636
C. eximium
4.06
3979
C. pubescens
4.47
4381
C. campylopodium
5.14
5032
C. parvifolium/cardenasii
5.77
5655
However, Mascone claims his data supports his
hypothesis
• Increase in DNA amount is evolutionary
advancement
• C. chacoense most plesiomorphic (ancestral)
• C. campylopodium most advanced
• n=13 in more recently evolved
Mascone tree rooted
Least DNA
C. chacoense
C. annuum var. annuum
C. frutescens
C. chinense
C. baccatum var. pendulum
C. baccatum var. baccatum
C. baccatum var. umbilicatum
C. eximium
C. pubescens
Most DNA
C. campylopodium x=13
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C. parvifolium/cardenasii
Mascone
molecular
Least DNA
C. chacoense
C. annuum var. annuum
C. frutescens
C. chinense
C. baccatum var. pendulum
C. baccatum var. baccatum
C. baccatum var. umbilicatum
C. eximium
C. pubescens
Most DNA
C. campylopodium x=13
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C. parvifolium/cardenasii
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ancestral
X=13 species
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C. ciliatum
C. buforum
C. campylopodium
C. cornutum
C. schottianum
C. villosum
C. pereirae *
C. friburguense *
3 unnamed Capsicum
Capsicum flexuosum
n = 13
n = 12
Conclusion
•Capsicum needs more research
•Appears to be an x=12/x=13 split in distant past
•research hindered by incomplete sampling
•Difficult to study domestication when phylogeny
unresolved
•6 new species identified in last 8 years
Naga Morich
Following Photos unused in presentation
Cherrapeño
Cherry Pepper
Bolivian rainbow
Chilaca
Fluorescent
Fredrik from Amalfi
Jalapeño - Biker Billy
Lemon black pepper
Little nubian
O'odham Indian Piquin
Peter Pepper
Pimenta-Doce
Poblano
Suryamukhi
Tepin
Variegata
C. Frutescens
Naga Jolokia / Tezpur
PI451762
Tabasco
C02466
Antillerna (Paris)
C. chinense
Capsicum galapagoense
C. chacoense
PI560944 - Putapario
C. Pubescens
Capsicum eximium
praetermissum
C. ciliatum
Capsicum Cardenasii
C. tovarii