Lysine biosynthesis and secondary metabolite production in F. graminearum
G. WIESENBERGER (1), C. Schüller (1), M. Peruci (2), A. Parich (3), A. Malachová (3), F. Berthiller (3), R. Schuhmacher (3), G. Adam (1) (1) University of Natural Resources and Life Sciences, Vienna (BOKU), Department of Applied Genetics and Cell Biology, Austria; (2) University of Natural Resources and Life Sciences, Vienna (BOKU), Department of Applied Genetics and Cell Biology, Austria; (3) University of Natural Resources and Life Sciences, Vienna (BOKU), IFA Tulln, Center for Analytical Chemistry, Austria

Fusarium graminearum causes Fusarium Head Blight (FHB) of small grain cereals and ear rot of maize. It contains multiple polyketide synthases (PKS) and non-ribosomal peptide synthetases (NPS) in secondary metabolite biosynthesis gene clusters. Post translational modification of PKS and NPS apo-proteins by phosphopantetheinyl transferase (PPT) is required for functional enzymes. Disruption of the PPT1 gene leads to simultaneous inactivation of all PKSs and NPSs, and to lysine auxotrophy, since Lys2 also requires phosphopantetheinylation. Fungal lysine auxotrophy alone affects virulence on host plants, thus we plan to uncouple the effect of ppt1 disruption on primary and (PKS and NPS dependent) secondary metabolism by replacing the Fusarium genes PPT1/LYS2 by the specialized gene pair LYS5/LYS2 from Saccharomyces cerevisiae (which is devoid of PKS and NPS genes). So far we were unable to complement the Fg lys2 deletion with Sc LYS2, probably due to aberrant RNA processing. We performed wheat infection experiments and metabolite analyses with Fusarium strains lacking LYS2 and/or PPT1. Interestingly, ppt1 mutants exhibit strongly reduced production of deoxynivalenol, culmorin and butenolide, and also volatile production was markedly different. The impact of disruption of FgPPT1 is therefore more complex than anticipated, so that reduced virulence cannot be attributed specifically to the lack of PKS and NPS activity.

Abstract Number: P7-218
Session Type: Poster