Polyploidy, its occurrence in plants, consequences and evolutionary significance. Lecture to Japanese Genetics Society, Okayama, September 2017. Covering wheat and its evolution
Pat (JS) Heslop-HarrisonProfessor of Genetics and Research Consultant at Pat Heslop-Harrison University of Leicester South China Botanical Garden
5. Hsu, Tao-Chiuh. Mammalian chromosomes in vitro. I. The karyotype of man. J. Hered. 1952.
TC (Tao-chiuh) Hsu
April 17, 1917 – July 9, 2003
Tjio & Levan 1956: 2n=46
6. CHAPTER 24:
THE FUTURE
“Probably the most pressing
problem in chromosome
research is the understanding of
the molecular architecture of the
chromosomes”
“Evolutionary studies using
cytogenetic characteristics
should gain more sophistication
and momentum”
1979
14. Inheritance of Chromosome 5D
dpTa1
×Aegilopsventricosa DDNN
ABDN
AABBDDNN Marne
AABBDD
VPM1
×
Triticum persicum Ac.1510 AABB
VPM1:
The entire original
chromosome from
Ae. ventricosa is not
transferred, but a
small is translocated
to the Marne 5D
15. Inheritance of Chromosome 5D
dpTa1
×Aegilopsventricosa DDNN
ABDN
AABBDDNN Marne
AABBDD
CWW1176-4
Rendezvous
Piko
VPM1 Dwarf A
96ST61
Virtue
×
×
×
Hobbit
× {Kraka×(Huntsman × Fruhgold)}
Triticum persicum Ac.1510 AABB
VPM1:
The original
chromosome from
Ae. ventricosa is not
transferred, but a
small segment is
translocated to the
Marne 5D
transferred to further
recombinant 5D chromosomes
18. Wheat 5AS.5RL at meiosis
Schwarzacher 1997 Plant Sexual Reproduction 10, 324-331
Meiotic interphase Leptotene
Zygotene Pachytene MI
20. Saffron
Crocus sativus
2n=3x=24
Minimal if any genetic variation
Vegetatively propagated
Grown (China), Kashmir, Europe, Iran
Most valuable agricultural/farmed product
AlSayied, HH et al. 2015. Ann Bot
21. Identical patterns in fingerprint gel with
diverse Saffron accessions (18=garden-hyb)
Nouf Alsayied, HH et al Ann Bot 2015
22. Variable patterns in 11 Crocus species,
including intra-specific variation
(19-21 and 22-24)
Saffron 1-5
24. A garden plant in UK : Crocus ‘Golden Yellow’ triploid 2n=3x=14
C. flavus 2n=2x=8 (8 yellow) C. angustifolius 2n=2x=12 (6 green)
Orgaard, Jacobsen & HH
‘Stellaris’ hybrid diploid 2n=2x=10
C. flavus 2n=2x=8 (4 green)
C. angustifolius 2n=2x=12 (6 blue)
Orgaard & HH, Ann Bot
25. Metaphase I in triploid hybrid Golden Yellow Crocus
Four bivalents C. flavus (2n=2x=8)-origin chromosomes
Six univalents C. angustifolius (2n=2x=12)
26. Origins of Crocus sativus
(Not only from C. cartwrightianus by
autotriploidy)
C. cartwrightianus crossed with a related
species involving unreduced gamete
F1 hybrid between 2 species crossed with
3rd species with an unreduced gamete
AAA AA’B ABC
5 III + 3 II + 3 I
8 III ?
John Bailey, Farah Badakshi, Nouf Alsayied, Trude Schwarzacher
Genomic constitution
28. Mid Zygotene Pachytene DiploteneEarly Zygotene
Dynamics of centromeres during meiosis in
6x wheat
CENH3 centromere
ASY1 associated with the lateral elements
ZYP1 central element of the synaptonemal complex
CENH3 centromere
ASY1 associated with the lateral elements
ZYP1 central element of the synaptonemal complex
Sepsi, Heslop-Harrison,
Schwarzacher et al.
Plant Journal 2017
29. (a) Interphase (b) Leptotene (c) Early Zygotene
CENH3TRSDAPICENH3ASY1CENH3ASY1
CENH3 centromere
ASY1 associated with the lateral elements
ZYP1 central element of the synaptonemal complex
30. Centromere dynamics and timing of chromosome synapsis (6x wheat)
Sepsi et al. Plant Journal 2017
0
5
10
15
20
25
30
35
40
Interphase Leptotene Early Mid-late Pachytene Diplotene
Zygotene Zygotene
2n=42
3 x 14
chromosomes
21 bivalents
3 x 7
pairs of
chromosomes
38. Th. intermedium
DNA
pSc119.2/CS13
4D
4D
4D T4DL*4Ai#2S
DAPI Afa Thin all
(blue) (green) (red)
Presence of T4DL recombinant
chromosome correlated with
resistance …
but some lines showed some
resistance without T4DL
Ali N, Heslop-Harrison JS, Ahmad H, Graybosch RA,
Hein GL, Schwarzacher T. (2016) Introgression of
chromosome segments from multiple alien species in wheat
breeding lines with wheat streak mosaic virus
resistance. Heredity 117: 114–123 10.1038/hdy.2016.36
39. SOME LINES ALSO
CARRY A THIN OR RYE
FRAGMENT ON
CHROMOSOME 1B
Th. intermedium
DNA
pSc119.2/CS13
Rye DNA
dpTa1/Afa
Ali N, Heslop-Harrison JS, Ahmad H, Graybosch RA,
Hein GL, Schwarzacher T. (2016) Introgression of
chromosome segments from multiple alien species in wheat
breeding lines with wheat streak mosaic virus
resistance. Heredity 117: 114–123 10.1038/hdy.2016.36
40. WHEAT TH. BESSARABICUM TRANSLOCATIONS
Patokar C, Sepsi A, Schwarzacher T, Kishii M, Heslop-
Harrison JS (2016) Molecular cytogenetic characterization of
novel wheat-Thinopyrum bessarabicum recombinant lines
carrying intercalary translocations. Chromosoma 125: 163-
172. 10.1007/s00412-015-0537-6
41. • Recent polyploidy
• Revealed by cytogenetics and hybridization
• Recent rearrangements or duplications
• Revealed by molecular cytogenetics
• Ancient, evolutionary polyploidy
• Revealed by sequencing
• Understanding polyploidy is important for speciation, evolution and
breeding
• Different sequence classes evolve at different rates and many are
saltatory rather than clocks
• Consequences and applications
42. Dasypyrum breviaristatum
2n=4x=28
Is it AAAA or AABB?
D. villosum (genomic DNA
green) × D. breviaristatum
(red)
Meiotic metaphase I in a F1
hybrid showing autotetraploid
nature
Galasso, Heslop-Harrison et al.
44. Fertility restorer
Rfk1 gene BAC
(yellow probe) in
turnip rape
(Brassica rapa)
2n=2x=20A+2R
metaphase with
radish (Raphanus)
chromosomes
(red)
Radish genomic red (labels 2
radish chromosomes and 45S
rDNA)
Rfk1 carrying BAC green labels
sites on radish and
homoeologous pair in Brassica
Tarja Niemelä,
Seppänen, Badakshi,
Rokka HH
Chromosome Research
2012
45. • Recent polyploidy
• Revealed by cytogenetics and hybridization
• Recent rearrangements or duplications
• Revealed by molecular cytogenetics
• Ancient, evolutionary polyploidy
• Revealed by sequencing
• Understanding polyploidy is important for speciation,
evolution and breeding
• Different sequence classes evolve at different rates and
many are saltatory rather than clocks
• Consequences and applications
47. BIODIVERSITY and genetic resources
Red - AAA
Palayam codan AAB (two bunch yellow, one green)
Peyan ABB (green cooking banana),
Njalipoovan AB (yellow)
Robusta AAA (green ripe)
Nendran AAB
Poovan AAB (one yellow bunch)
Red AAA
PeyanVarkala, Kerala, India
48. THE BANANA GENOME• Seven countries + international organization coordinated by Angelique D’Hont - France (CIRAD,
Genoscope)
51. A D’Hont et al. Nature 000, 1-5 (2012) doi:10.1038/nature11241
Whole-genome duplication events.
53. Petunia hybrida
P. inflata X P. axillaris
2n=14 x 2n=14
Bomberley, Kuhlemeier et al. 2016 Insight into the
evolution of the Solanaceae from the parental
genomes of Petunia hybrida. Nature Plants 2: article
number 16074.
See Supplementary paper 2 - Heslop-Harrison,
Schwarzacher, Richert-Poeggeler
www.molcyt.org/tag/Petunia
Diploid hybrid
Petunia Genome
Landscape
54. Sol-alpha:
Palaeohexaploidy in
Solanaceae
Paleopolyploidy events
followed by massive gene
loss and chromosomal
structural rearrangements
Gene fractionation is less
profound in Petunia
compared to tomato
Supplementary Paper 5
Incomplete gene fractionation
after paleopolyploidy: Petunia
Grandont, Tang, Johns, Lyons
and Schranz
To Bomberley et al. 2016
Genomes of Petunia hybrida.
Nature Plants 2: article number
16074
63. 2 End hunger, achieve food security, improve nutrition & promote
sustainable agriculture
15 Protect, restore and promote sustainable use of terrestrial
ecosystems … halt biodiversity loss
67. From Chromosome to Nucleus
Pat Heslop-Harrison phh4@le.ac.uk www.molcyt.com
68. Pat Heslop-Harrison
phh@molcyt.com
www.molcyt.com
89th Genetics Society of Japan Meeting
Centennial of the discovery of the correct
chromosome number and polyploidy in wheat
Polyploidy, its distribution and
evolutionary significance
Twitter: @pathh1
Slideshare pathh1
69. How to use diversity
• Cross two varieties
• Genome manipulations
• Cross two species and make a new one
• Cell fusion hybrids
• Chromosome manipulation
• Backcross a new species
• Generate recombinants
• Chromosome recombinations
• Transgenic approaches
• Use a new species
70. • Abiotic stresses – water, wind, nitrogen, plant
nutrition
• Biotic stresses – disease – competition,
nematodes, fungi, bacteria, viruses, rodents
• Environmental challenges
– Soil, water, climate change, sustainability
• Social challenges
– Urbanization, population growth, mobility of
people, under-/un-employment
– Farming is hard, long work – increased standard of
living
72. • 50% of the world's protein needs are
derived from atmospheric nitrogen fixed
by the Haber-Bosch process and its
successors.
• Global consumption of fertilizer
(chemically fixed nitrogen) 80 million
tonnes
• <<200 million tonnes fixed naturally
75. Conventional Breeding
Superdomestication
• Cross the best with the best and hope for something
better
• Decide what is wanted and then plan how to get it
– Variety crosses
– Mutations
– Hybrids (sexual or cell-fusion)
– Genepool
– Transformation
76. Economic growth
• Separate into increases in inputs
(resources, labour and capital) and
technical progress
• 90% of the growth in US output per
worker is attributable to technical
progress
Robert Solow – Economist
78. Are there many candidates?
• 250,000 plants
• 4,629 mammals
• 9,200 birds
• 10,000,000 insects
• But only 200 plants, 15 mammals, 5 birds
and 2 insects are domesticated!
79. Probably not many more
(at least for plants)
• Spread of the few species
• Little change since early agriculture
• Repeated domestication of these species
(sometimes)
• But wider use of current species with suitable
genetic changes, or of newly created hybrids
• A few species where wild-collections must be
replaced sustainably
• New needs – biofuels, neutraceuticals
82. Pat Heslop-Harrison
phh@molcyt.com
www.molcyt.com
89th Genetics Society of Japan Meeting
Centennial of the discovery of the correct
chromosome number and polyploidy in wheat
Polyploidy, its distribution and
evolutionary significance
Twitter: @pathh1
Slideshare pathh1