High homologous gene conservation despite extreme autopolyploid redundancy in sugarcane.

TitreHigh homologous gene conservation despite extreme autopolyploid redundancy in sugarcane.
Publication TypeJournal Article
Year of Publication2011
AuthorsGarsmeur, Olivier, Charron Carine, Bocs Stéphanie, Jouffe Vincent, Samain Sylvie, Couloux Arnaud, Droc Gaëtan, Zini Cyrille, Glaszmann Jean-Christophe, Van Sluys Marie-Anne, and D'Hont Angélique
JournalThe New phytologist
Date Published2011 Jan
Mots-clésAlleles, Chromosomes, Artificial, Bacterial, Conserved Sequence, DNA Transposable Elements, Genes, Plant, Haplotypes, Molecular Sequence Annotation, Oryza sativa, Phylogeny, Polyploidy, Saccharum, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid, Sorghum, Synteny

Modern sugarcane (Saccharum spp.) is the leading sugar crop and a primary energy crop. It has the highest level of 'vertical' redundancy (2n=12x=120) of all polyploid plants studied to date. It was produced about a century ago through hybridization between two autopolyploid species, namely S. officinarum and S. spontaneum. In order to investigate the genome dynamics in this highly polyploid context, we sequenced and compared seven hom(oe)ologous haplotypes (bacterial artificial chromosome clones). Our analysis revealed a high level of gene retention and colinearity, as well as high gene structure and sequence conservation, with an average sequence divergence of 4% for exons. Remarkably, all of the hom(oe)ologous genes were predicted as being functional (except for one gene fragment) and showed signs of evolving under purifying selection, with the exception of genes within segmental duplications. By contrast, transposable elements displayed a general absence of colinearity among hom(oe)ologous haplotypes and appeared to have undergone dynamic expansion in Saccharum, compared with sorghum, its close relative in the Andropogonea tribe. These results reinforce the general trend emerging from recent studies indicating the diverse and nuanced effect of polyploidy on genome dynamics.

Alternate JournalNew Phytol.