A fragmented aflatoxin-like gene cluster in the forest pathogen Dothistroma septosporum.
The polyketide toxin dothistromin is very similar in structure to the aflatoxin precursor, versicolorin B. Dothistromin is made by a pine needle pathogen, Dothistroma septosporum, both in culture and in planta. Orthologs of aflatoxin biosynthetic genes have been identified that are required for dothistromin biosynthesis in D. septosporum. In contrast to the situation in aflatoxin-producing fungi where 25 aflatoxin biosynthetic and regulatory genes are tightly clustered in one region of the genome, the dothistromin gene cluster is fragmented. Three mini-clusters of dothistromin genes have been identified, each located on a 1.3-Mb chromosome and each grouped with non-dothistromin genes. There are no obvious patterns of repeated sequences or transposon relics to suggest recent recombination events. Most dothistromin genes within the mini-clusters are co-regulated, suggesting that coordinate control of gene expression is achieved despite this unusual arrangement of secondary metabolite biosynthetic genes.
Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
Shuguang
S
Zhang
Arne
A
Schwelm
Hongping
H
Jin
Lesley J
LJ
Collins
Rosie E
RE
Bradshaw
D000348:Aflatoxins / Q000235:genetics* / Q000378:metabolism; D000880:Anthraquinones / Q000378:metabolism; D001203:Ascomycota / Q000235:genetics* / Q000378:metabolism; D023061:Gene Order; D008969:Molecular Sequence Data; D005810:Multigene Family; D017422:Sequence Analysis, DNA; D014197:Trees / Q000382:microbiology
D000348:Aflatoxins; D000880:Anthraquinones; C042735:dothistromin; C029827:versicolorin C