Early expression of aflatoxin-like dothistromin genes in the forest pathogen Dothistroma septosporum

A fragmented aflatoxin-like gene cluster in the forest pathogen Dothistroma septosporum

“…Using the same strategy, clones generated from the XbaI digest were screened using a DIGlabeled PCR product amplified from D. septosporum vbsA using primers vbs-1aF/vbs-4R, which are degenerate primers that amplify a 1.3 kb fragment of the vbsA gene. The isolation of this gene fragment was described previously (Schwelm et al, 2007). In each case, positively hybridizing clones were sequenced by primer walking.…”

“…Regions labeled with Accession Nos. AF448056 (Bradshaw et al, 2002), EF177826 (Schwelm et al, 2007), and DQ149246 (Bradshaw et al, 2006) were previously sequenced GenBank submissions; these have now been updated to include new sequence. Horizontal bars below the constructs indicate the regions amplified by PCR using genomic DNA as template for confirmation of the integrity of the assembled DNA sequences (each horizontal bar under the illustrated overlapping sequences indicates an individual PCR).…”

The veA gene of the pine needle pathogen Dothistroma septosporum regulates sporulation and secondary metabolism

“…2) and small growth-rate differences. In our experience, phenotypic variability is seen even between wild-type clonal isolates of D. septosporum (Schwelm et al, 2008), hence the differences seen between KO1 and KO2 are not surprising. It is also possible that small differences in recombination sites during the gene knockout process could affect other regulatory molecules such as overlapping non-coding transcripts that have been shown to affect chromatin structure in some species (Wei et al, 2011).…”

“…However unlike AF genes, dothistromin genes are not tightly clustered, but are arranged in several mini-clusters on a 1.3 Mb chromosome (Bradshaw et al, 2006;Schwelm and Bradshaw, 2010). Furthermore, dothistromin is produced mainly during early exponential phase in culture, instead of during late exponential and stationary phases as is normally seen for secondary metabolites such as AF (Schwelm et al, 2008). Whether this unusual expression pattern is also seen in planta is not yet known, and likewise the role of dothistromin is not known.…”

A strain of Fusarium kyushuense is able to produce aflatoxin B1 and G1

“…Interestingly often homologues of the nor-1 gene can be found for example in P. roqueforti, N. crassa and other species like Mycosphaerella, Magnaporthe or Cochliobolus (Geisen 1996;Ehrlich 2006). A gene cluster of Dothistroma pini, a fungus which produces dothistromin, a secondary metabolite with similarities to sterigmatocystin, has some homologies to the aflatoxin gene cluster (Ehrlich 2006;Schwelm et al 2008). …”