SsCyp86 modulates sporisorium scitamineum mating/filamentation and pathogenicity through regulating fatty acid metabolism.

BACKGROUND: Fatty acid metabolism constitutes a significant and intricate biochemical process within microorganisms. Cytochrome P450 (CYP450) enzymes are found in most organisms and occupy a pivotal position in the metabolism of fatty acids. However, the role of CYP450 enzyme mediated fatty acid metabolism in the pathogenicity of pathogenic fungi remains unclear. METHODS: In this study, a CYP450 enzyme-encoding gene, SsCYP86, was identified in the sugarcane smut fungus Sporisorium scitamineum and its functions were characterized using a target gene homologous recombination strategy and metabonomics. RESULTS: We found that the expression of SsCYP86 was induced by or sugarcane wax or under the condition of mating/filamentation. Sexual reproduction assay demonstrated that the SsCYP86 deletion mutant was defective in mating/filamentation and significantly reduced its pathogenicity. Further fatty acid metabolomic analysis unravelled the levels of fatty acid metabolites were reduced in the SsCYP86 deletion mutant. Exogenous addition of fatty acid metabolites cis-11-eicosenoic acid (C20:1N9), pentadecanoic acid (C15:0), and linolenic acid (C18:3N3) partially restored the mating/filamentation ability of the SsCYP86 deletion mutant and restored the transcriptional level of the SsPRF1, a pheromone response transcription factor that is typically down-regulated in the absence of SsCYP86. Moreover, the constitutive expression of SsPRF1 in the SsCYP86 deletion mutant restored its mating/filamentation. CONCLUSION: Our results indicated that SsCyp86 modulates the SsPRF1 transcription by fatty acid metabolism, and thereby regulate the sexual reproduction of S. scitamineum. These findings provide insights into how CYPs regulate sexual reproduction in S. scitamineum.

Discovery of N-Benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine as a Potential Antifungal Agent against Sporidia Growth and Teliospore Germination of Sporisorium scitamineum.

The cultivation of sugar cane using perennial roots is the primary planting method, which is one of the reasons for the serious occurrence of sugar cane smut disease caused by the basidiomycetous fungus Sporisorium scitamineum in the sugar cane perennial root planting area. Consequently, it is crucial to eliminate pathogens from perennial sugar cane buds. In this study, we found that MAP kinase Hog1 is necessary for heat stress resistance. Subsequent investigations revealed a significant reduction in the expression of the heat shock protein 104-encoding gene, SsHSP104, in the ss1hog1Δ mutant. Additionally, the overexpression of SsHSP104 partially restored colony growth in the ss1hog1Δ strain following heat stress treatment, demonstrating the crucial role of SsHsp104 in SsHog1-mediated heat stress tolerance. Hence, we constructed the ss1hsp104:eGFP fusion strain in the wild type of S. scitamineum to identify small-molecule compounds that could inhibit the heat stress response, leading to the discovery of N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine as a potential compound that targets the SsHog1 mediation SsHsp104 pathway during heat treatment. Furthermore, the combination of N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine and warm water treatment (45 °C for 15 min) inhibits the growth of S. scitamineum and teliospore germination, thereby reducing the occurrence of sugar cane smut diseases and indicating its potential for eliminating pathogens from perennial sugar cane buds. In conclusion, these findings suggest that N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine is promising as a targeted compound for the SsHog1-mediated SsHsp104 pathway and may enable the reduction of hot water treatment duration and/or temperature, thereby limiting the occurrence of sugar cane smut diseases caused by S. scitamineum.

Cytochrome c-peroxidase modulates ROS homeostasis to regulate the sexual mating of Sporisorium scitamineum.

IMPORTANCE: Reactive oxygen species play an important role in pathogen-plant interactions. In fungi, cytochrome c-peroxidase maintains intracellular ROS homeostasis by utilizing H2O2 as an electron acceptor to oxidize ferrocytochrome c, thereby contributing to disease pathogenesis. In this study, our investigation reveals that the cytochrome c-peroxidase encoding gene, SsCCP1, not only plays a key role in resisting H2O2 toxicity but is also essential for the mating/filamentation and pathogenicity of S. scitamineum. We further uncover that SsCcp1 mediates the expression of SsPrf1 by maintaining intracellular ROS homeostasis to regulate S. scitamineum mating/filamentation. Our findings provide novel insights into how cytochrome c-peroxidase regulates sexual reproduction in phytopathogenic fungi, presenting a theoretical foundation for designing new disease control strategies.