ARS | Publication request: Genetic Diversity of Polyketide Synthase/Nonribosomal Peptide Synthetase Genes in Isolates of the Barley Net Blotch Fungus Pyrenophora teres f. teres

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 4, 2009
Publication Date: June 1, 2009
Citation: Lu, S., Friesen, T.L. 2009. Genetic Diversity of Polyketide Synthase/Nonribosomal Peptide Synthetase Genes in Isolates of the Barley Net Blotch Fungus Pyrenophora teres f. teres. Meeting Abstract 99:S77

Technical Abstract: Polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) are multifunctional enzymes responsible for biosynthesis of diverse small molecules (e.g., mycotoxins and phytotoxins) in filamentous ascomycetes. Both PKS and NRPS genes are present in fungal genomes as large gene families but only a few have been shown to be involved in pathogenesis. We have identified three PKS genes and six NRPS genes from the barley net blotch fungus Pyrenophora teres f. teres (Ptt). Each PttPKS/NRPS gene has been amplified by PCR from a total of twenty-three Ptt isolates collected from different geographic regions including Japan, Brazil and the USA. DNA sequencing indicates that PttPKS1, 2, NRPS1, 2 and 3, which are highly conserved (>90% similarity) in the closely related tan spot fungus P. tritici-repentis (Ptr), have little variation among different Ptt isolates. In contrast, PttPKS3, NRPS4, 5 and 6, which are only weakly or moderately conserved (50-68% similarity) in Ptr, appear to be significantly divergent in Ptt populations. Differential PCR primers have revealed polymorphic patterns in PttPKS3 (from one Japanese isolate), NRPS4 (from three North Dakota isolates) and NRPS6 (from one Japanese, one Brazilian and two ND isolates), which is likely paralogous to NRPS5. These polymorphic PttPKS/NRPS genes will be further investigated through genetic and functional analyses for potential roles in mediating pathogen-host interactions in the Ptt-barley pathosystem.