Ring Closure Reactions of Phenylphenalenones and Musellarins in Musaceae infected with reporter fluorescent Fusarium odoratissmum Tropical Race 4

• Applicant: Dr. Dirk Jürgen Hölscher
• Subject Area: Plant Breeding and Plant Pathology ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533861813

The project investigates important parts of the interaction of bananas with the fungus Fusarium odoratissimum Tropical Race 4 (TR4; previously known as Fusarium oxysporum f. sp. cubense Race 1 (Foc R1)), which currently threatens global banana production. This grant proposal consists of six work passages (WP1-WP6). The cultivation of two different banana varieties with different degrees of resistance to TR4 and the TR4 inoculation of the two banana varieties (WP1) allows the determination of the phytochemical profiles and of the distribution of isotopes, especially Cu and S at a cellular level. The location where these processes take place will be determined by a combination of different mass spectrometry-techniques (WP2). High-resolution transcriptome mapping of the Musa-TR4-interaction using fluorescent reporter Fusarium TR4 will be performed to generate spatially resolved gene expression maps. Single molecule fluorescent in-situ hybridization (smFISH) will be carried out to confirm spatiotemporal gene expression of selected PP/ML biosynthesis genes (polyphenol oxidases (PPOs)) (WP3). The fundamental basic of our project are hypothetical detailed mechanistic considerations of the reaction sequences of the biosynthesis of phenylphenalenones (PPs) and musellarins (MLs), and an evaluation of the significant genetic information of the Musa genome and Musa transcriptomes. especially enabling the assignment of our key research enzymes, the PPOs (WP4 and WP5). Working package WP4 deals with the formation of o-dihydroxy compounds and o-quinones of diarylheptanoids, the subsequent ring closure reactions of the diarylheptanoids and the enzymatically catalyzed formation of aromatic systems of the PPs and MLs. PPOs are our key research enzyme candidates for these reaction steps. PPOs are to be processed by molecular biology and characterized by biochemical and X-ray crystal structure analysis (WP5). Finally, possible antifungal effects of PPs and MLs and their Cu complexes are to be investigated in bioassays (WP6).

• DFG Programme: Research Grants
• International Connection: Austria
• Partner Organisation: Fonds zur Förderung der wissenschaftlichen Forschung (FWF)
• Cooperation Partners: Professorin Dr.-Ing. Heidi Halbwirth; Dr. Christian Molitor