Email updates

Keep up to date with the latest news and content from Genome Biology and BioMed Central.

Open Access Research

The role of transposable element clusters in genome evolution and loss of synteny in the rice blast fungus Magnaporthe oryzae

Michael R Thon1*, Huaqin Pan2, Stephen Diener2, John Papalas2, Audrey Taro2, Thomas K Mitchell2 and Ralph A Dean2

Author Affiliations

1 Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA

2 Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27695, USA

For all author emails, please log on.

Genome Biology 2006, 7:R16  doi:10.1186/gb-2006-7-2-r16

Published: 28 February 2006

Abstract

Background

Transposable elements are abundant in the genomes of many filamentous fungi, and have been implicated as major contributors to genome rearrangements and as sources of genetic variation. Analyses of fungal genomes have also revealed that transposable elements are largely confined to distinct clusters within the genome. Their impact on fungal genome evolution is not well understood. Using the recently available genome sequence of the plant pathogenic fungus Magnaporthe oryzae, combined with additional bacterial artificial chromosome clone sequences, we performed a detailed analysis of the distribution of transposable elements, syntenic blocks, and other features of chromosome 7.

Results

We found significant levels of conserved synteny between chromosome 7 and the genomes of other filamentous fungi, despite more than 200 million years of divergent evolution. Transposable elements are largely restricted to three clusters located in chromosomal segments that lack conserved synteny. In contradiction to popular evolutionary models and observations from other model organism genomes, we found a positive correlation between recombination rate and the distribution of transposable element clusters on chromosome 7. In addition, the transposable element clusters are marked by more frequent gene duplications, and genes within the clusters have greater sequence diversity to orthologous genes from other fungi.

Conclusion

Together, these data suggest that transposable elements have a profound impact on the M. oryzae genome by creating localized segments with increased rates of chromosomal rearrangements, gene duplications and gene evolution.