Abstract:
The Gibberella fujikuroi complex includes many Fusarium species that cause
significant losses in yield and quality of agricultural and forestry crops. Due to their
economic importance, whole-genome sequence information has rapidly become
available for species including Fusarium circinatum, Fusarium fujikuroi and
Fusarium verticillioides, each of which represent one of the three main clades
known in this complex. However, no previous studies have explored the genomic
commonalities and differences among these fungi. In this study, a previously
completed genetic linkage map for an interspecific cross between Fusarium
temperatum and F. circinatum, together with genomic sequence data, was utilized
to consider the level of synteny between the three Fusarium genomes. Regions that
are homologous amongst the Fusarium genomes examined were identified using in
silico and pyrosequenced amplified fragment length polymorphism (AFLP)
fragment analyses. Homology was determined using BLAST analysis of the
sequences, with 777 homologous regions aligned to F. fujikuroi and F. verticillioides.
This also made it possible to assign the linkage groups from the interspecific cross
to their corresponding chromosomes in F. verticillioides and F. fujikuroi, as well as to
assign two previously unmapped supercontigs of F. verticillioides to probable
chromosomal locations. We further found evidence of a reciprocal translocation
between the distal ends of chromosome 8 and 11, which apparently originated
before the divergence of F. circinatum and F. temperatum. Overall, a remarkable
level of macrosynteny was observed among the three Fusarium genomes, when comparing AFLP fragments. This study not only demonstrates how in silico AFLPs
can aid in the integration of a genetic linkage map to the physical genome, but it
also highlights the benefits of using this tool to study genomic synteny and
architecture.
