Independent wheat B and G genome origins in outcrossing Aegilops progenitor haplotypes.
The origin of modern wheats involved alloploidization among related genomes. To determine if Aegilops speltoides was the donor of the B and G genomes in AABB and AAGG tetraploids, we used a 3-tiered approach. Using 70 amplified fragment length polymorphism (AFLP) loci, we sampled molecular diversity among 480 wheat lines from their natural habitats encompassing all S genome Aegilops, the putative progenitors of wheat B and G genomes. Fifty-nine Aegilops representatives for S genome diversity were compared at 375 AFLP loci with diploid, tetraploid, and 11 nulli-tetrasomic Triticum aestivum wheat lines. B genome-specific markers allowed pinning the origin of the B genome to S chromosomes of A. speltoides, while excluding other lineages. The outbreeding nature of A. speltoides influences its molecular diversity and bears upon inferences of B and G genome origins. Haplotypes at nuclear and chloroplast loci ACC1, G6PDH, GPT, PGK1, Q, VRN1, and ndhF for approximately 70 Aegilops and Triticum lines (0.73 Mb sequenced) reveal both B and G genomes of polyploid wheats as unique samples of A. speltoides haplotype diversity. These have been sequestered by the AABB Triticum dicoccoides and AAGG Triticum araraticum lineages during their independent origins.
Kilian
B
B
Max Planck Institute for Plant Breeding Research, Köln, Germany.
Ozkan
H
H
Deusch
O
O
Effgen
S
S
Brandolini
A
A
Kohl
J
J
Martin
W
W
Salamini
F
F
D003433:Crosses, Genetic; D018745:Genome, Plant; D006239:Haplotypes; D006824:Hybridization, Genetic; D010802:Phylogeny; D006109:Poaceae / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011123:Polyploidy; D014908:Triticum / Q000235:genetics*