Aegilops speltoides Ph1 suppressors

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Aegilops speltoides Ph1 suppressors Practical
utility for wheat
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Chromosome 5B is responsible for diploid-like
meiotic chromosome pairing in hexaploid T.
aestivum
Euploid
Nullisomic 5B
R. Riley, Heredity 15407-429, 1960
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Triticum urartu (AA genomes)
Wild emmer wheat (AABB genomes )
Aegilops speltoides SS genomes (extant relative
of the B genome)
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Aegilops speltoides
Surprisingly, Ae. speltoides was found to not
have Ph1 but to promote homoeologous pairing in
wheat.
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T. aestivum x Ae. speltoides
Ph1 suppression is controlled by two unlinked
duplicated major genes and several minor genes
K.C. Chen and J. Dvorak, Can. J. Genet.
Cytol. 26279-287, 1983
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Mean numbers of chiasmata per cell in hybrids
involving low- and high-pairing Ae. speltoides
inbred lines
low-pairing
high pairing
Ae. speltoides x Ae. tauschii
Ae. speltoides x Ae. caudata
No. chismata
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The average chiasma number per cell in hybrids T.
aestivum backcrosses x Ae. variabilis
Chen et al. TAG 8897-101, 1994
16
14
12
10
Mean chiasma number
8
6
4
2
0
low int. PhI
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Comparison of Ae. speltoides chromosome 1S and T.
monococcum chromosome 1Am genetic maps
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Comparison of Ae. speltoides chromosome 3S and T.
monococcum chromosome 3Am genetic maps
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• 590 hybrids were produced, no. chiasmata per cell
  was estimated, DNA were isolated, and Southern
  blots were hybridized with informative markers

• The population of 590 hybrids was
  partitioned by marker allele

• ANOVAs were computed to determine marker
  effect on pairing

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Increase in the mean number of chiasmata per cell
over background ( 7 chiasmata per cell)
10
9
8
7
6
5
Mean no. chiasmata per cell
4
3
2
1
0
5S
13
Increase in the mean number of chiasmata per cell
over background ( 7 chiasmata per cell)
10
9
8
7
6
5
Mean no. chiasmata per cell
4
3
2
1
0
5S
7S
3S
3S7S
3S7S5S
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Increase in the mean number of chiasmata per cell
over background ( 7 chiasmata per cell)
10
9
8
7
6
5
Mean no. chiasmata per cell
4
3
2
1
0
5S
7S
3S
3S7S
3S7S5S
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Increase in the mean number of chiasmata per cell
over background ( 7 chiasmata per cell)
10
9
8
7
6
5
Mean no. chiasmata per cell
4
3
2
1
0
5S
7S
3S
3S7S
3S7S5S
16
Increase in the mean number of chiasmata per cell
over background ( 7 chiasmata per cell)
10
9
8
7
6
5
Mean no. chiasmata per cell
4
3
2
1
0
5S
7S
3S
3S7S
3S7S5S
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Segregation of Su1-Ph1 in T. aestivum x Ae.
speltoides hybrids
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Effect of segregation for Su1-Ph1 on meiotic
pairing in T. aestivum x Ae. speltoides hybrids
-

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Genetic maps of the Su1-Ph1 region in Ae.
speltoides
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PCR assay for marker PSR1205 using Ae. speltoides
genome specific primers
Chinese Spring
BC4 wheat segregant without Ph1-Su1
Ae. speltoides
BC4 wheat segregant with Ph1-Su1
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The average chiasma number per cell in hybrids T.
aestivum backcrosses x Ae. variabilis
Chen et al. TAG 8897-101, 1994
16
14
12
10
Mean chiasma number
8
6
4
2
0
low int. PhI
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The average chiasma number per cell in hybrids T.
aestivum backrosses x Ae. variabilis
Chen et al. TAG 8897-101
Su1-Ph1 data
Mean chiasma number
low int PhI
Su1-Ph1 -
Su1-Ph1
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The use of Ph1-Su1 in alien gene transfer in wheat
Alien DS line x Ph1-Su1 line
F1 targeted recombination between the alien
chromosome and wheat homoeologue
BC1 select recombinants without Ph1-Su1 using
molecular markes
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Acknowledgements
Kuey-Chu Chen Ming-Cheng Luo Karin R. Deal
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