Reference "Genes encoding plastid acetyl-CoA carboxylase and 3-phosphoglycerate kinase of the Triticum/Aegilops complex and the evolutionary history of polyploid wheat"

Reference ID

7653

Title

Genes encoding plastid acetyl-CoA carboxylase and 3-phosphoglycerate kinase of the Triticum/Aegilops complex and the evolutionary history of polyploid wheat

Source

Proceedings of the National Academy of Sciences of the United States of America, 2002, vol. 99, pp. 8133-8138

Authors (7)

Huang-S	Sirikhachornkit-A
Su-X	Faris-J
Gill-B	Haselkorn-R
Gornicki-P

Abstract

The classic wheat evolutionary history is one of adaptive radiation of the
diploid Triticum/Aegilops species (A, S, D), genome convergence and divergence
of the tetraploid (Triticum turgidum AABB, and Triticum timopheevii AAGG) and
hexaploid (Triticum aestivum, AABBDD) species. We analyzed Acc-1 (plastid acetyl-
CoA carboxylase) and Pgk-1 (plastid 3-phosphoglycerate kinase) genes to
determine phylogenetic relationships among Triticum and Aegilops species of the
wheat lineage and to establish the timeline of wheat evolution based on gene
sequence comparisons. Triticum urartu was confirmed as the A genome donor of
tetraploid and hexaploid wheat. The A genome of polyploid wheat diverged from
T. urartu less than half a million years ago (MYA), indicating a relatively
recent origin of polyploid wheat. The D genome sequences of T. aestivum and
Aegilops tauschii are identical, confirming that T. aestivum arose from
hybridization of T. turgidum and Ae. tauschii only 8,000 years ago. The diploid
Triticum and Aegilops progenitors of the A, B, D, G, and S genomes all radiated
2.5-4.5 MYA. Our data suggest that the Acc-1 and Pgk-1 loci have different
histories in different lineages, indicating genome mosaicity and significant
intraspecific differentiation. Some loci of the S genome of Aegilops speltoides
and the G genome of T. timophevii are closely related, suggesting the same
origin of some parts of their genomes. None of the Aegilops genomes analyzed is
a close relative of the B genome, so the diploid progenitor of the B genome
remains unknown.