Bartoš, J., Vlček, Č., Choulet, F., Džunková, M., Cviková, K., Šafář, J., Šimková, H., Pačes, J., Strnad, H., Sourdille, P., Bergés, H., Cattonaro, F., Feuillet, C., Doležel, J.
BMC PLANT BIOLOGY
12:
155,
2012
Klíčová slova:
Wheat, BAC sequencing, Homoeologous genomes, Gene duplication, Non-collinear genes, Allopolyploidy
Abstrakt:
Background: Polyploidization is considered one of the main mechanisms of plant genome evolution. The
presence of multiple copies of the same gene reduces selection pressure and permits sub-functionalization and
neo-functionalization leading to plant diversification, adaptation and speciation. In bread wheat, polyploidization
and the prevalence of transposable elements resulted in massive gene duplication and movement. As a result, the
number of genes which are non-collinear to genomes of related species seems markedly increased in wheat.
Results: We used new-generation sequencing (NGS) to generate sequence of a Mb-sized region from wheat
chromosome arm 3DS. Sequence assembly of 24 BAC clones resulted in two scaffolds of 1,264,820 and 333,768
bases. The sequence was annotated and compared to the homoeologous region on wheat chromosome 3B and
orthologous loci of Brachypodium distachyon and rice. Among 39 coding sequences in the 3DS scaffolds, 32 have a
homoeolog on chromosome 3B. In contrast, only fifteen and fourteen orthologs were identified in the
corresponding regions in rice and Brachypodium, respectively. Interestingly, five pseudogenes were identified
among the non-collinear coding sequences at the 3B locus, while none was found at the 3DS locus.
Conclusion: Direct comparison of two Mb-sized regions of the B and D genomes of bread wheat revealed similar
rates of non-collinear gene insertion in both genomes with a majority of gene duplications occurring before their
divergence. Relatively low proportion of pseudogenes was identified among non-collinear coding sequences. Our
data suggest that the pseudogenes did not originate from insertion of non-functional copies, but were formed later
during the evolution of hexaploid wheat. Some evidence was found for gene erosion along the B genome locus.
Fulltext: kontaktujte autory z ÚEB
Autoři z ÚEB: Jan Bartoš,
Kateřina Cviková,
Jaroslav Doležel,
Jan Šafář,
Hana Šimková
Čeština
English