title: Strain-specific polyketide synthase genes of Aspergillus niger.
abstract: In silico comparison of 34 putative pks genes in Aspergillus niger strain CBS 513.88 versus A. niger strain ATCC 1015 genome revealed significant nucleotide identity (>95% covering a minimum of 99% of the gene sequence) for 31 of these genes (approximately 91%). A. niger CBS 513.88 harbors three putative pks genes (An01g01130, An11g05940, and An15g07920), for which nucleotide identity was not found in A. niger ATCC 1015. To compare the results of the in silico analysis with the in vivo situation, experimental data were obtained for a large number of A. niger strains obtained from different substrates and geographical regions. Three putative pks genes that were found to be variable between the two A. niger strains using bioinformatics tools were in fact strain-specific genes based on experimental data. The PCR amplification signals for the An01g01130, An11g05940, and An15g07920 pks genes were detected in only 97%, 71%, and 26% of the strains, respectively. Southern blot analyses confirmed the PCR data. Because one of the strain-specific pks genes (An15g07920) is located in a putative ochratoxin cluster, we focused our investigation on that region. We assessed the ochratoxin production capability of the 119 A. niger strains and found a positive association between the presence of this pks gene and the capability of the respective strain to produce ochratoxin.
authors.affiliation: Universidade Estadual de Londrina, Centro de Ciências Biológicas, P.O. Box 6001, 86051-990 Londrina, Brazil.
authors.forename: Lara Munique
authors.initials: LM
authors.lastname: Ferracin
authors.forename: Carla Beatriz
authors.initials: CB
authors.lastname: Fier
authors.forename: Maria Lucia Carneiro
authors.initials: ML
authors.lastname: Vieira
authors.forename: Claudia Barros
authors.initials: CB
authors.lastname: Monteiro-Vitorello
authors.forename: Alessandro de Mello
authors.initials: Ade M
authors.lastname: Varani
authors.forename: Maria Magdalena
authors.initials: MM
authors.lastname: Rossi
authors.forename: Marcelo
authors.initials: M
authors.lastname: Müller-Santos
authors.forename: Marta Hiromi
authors.initials: MH
authors.lastname: Taniwaki
authors.forename: Beatriz
authors.initials: B
authors.lastname: Thie Iamanaka
authors.forename: Maria Helena Pelegrinelli
authors.initials: MH
authors.lastname: Fungaro
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology* / Q000235:genetics; D019295:Computational Biology; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D014644:Genetic Variation; D005810:Multigene Family; D009793:Ochratoxins / Q000096:biosynthesis*; D048630:Polyketide Synthases / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004271:DNA, Fungal; D009793:Ochratoxins; C025589:ochratoxin A; D048630:Polyketide Synthases