Sensitivity of Globisporangium ultimum to the fungicide metalaxyl is enhanced by the infection with a toti-like mycovirus

• Published in: Microbiological research 2024-08, Vol.285, p.127742-127742, Article 127742
• Main Authors: Higuchi, Aika, Tojo, Motoaki, Mochizuki, Tomofumi
• Format: Article
• Language: English
• Subjects: ABC-type transporter; Alanine - analogs & derivatives; Alanine - pharmacology; Fungal Viruses - drug effects; Fungal Viruses - genetics; Fungal Viruses - isolation & purification; Fungal Viruses - physiology; Fungicide sensitivity; Fungicides, Industrial - pharmacology; Gene Expression Profiling; Hyphae - drug effects; Hyphae - growth & development; Japan; Metalaxyl; Mycelium - drug effects; Mycelium - growth & development; Mycelium - virology; Mycovirus; Oomycetes; Plant Diseases - microbiology; Plant Diseases - virology; Pythium - drug effects; Pythium - growth & development; RNA Viruses - drug effects; RNA Viruses - genetics; Transcriptome; Transcriptome analysis
• ISSN: 0944-5013; 1618-0623
• DOI: 10.1016/j.micres.2024.127742

In recent years, numerous oomycete mycoviruses have been discovered; however, very few studies have focused on their effects on the host oomycete phenotype. In this study, we investigated the impact of toti-like Pythium ultimum RNA virus 2 (PuRV2) infection on the phytopathogenic soil-borne oomycete Globisporangium ultimum, which serves as a model species for Globisporangium and Pythium, specifically the UOP226 isolate in Japan. We generated a PuRV2-free isogenic line through hyphal tip isolation using high-temperature culture and subsequently compared the phenotypic characteristics and gene expression profiles of UOP226 and the PuRV2-free isogenic line. Our findings revealed that the metalaxyl sensitivity of UOP226 was greater than that of the PuRV2-free isogenic line, whereas the mycelial growth rate and colony morphology remained unchanged in the absence of the fungicide. Furthermore, transcriptome analyses using RNA-seq revealed significant downregulation of ABC-type transporter genes, which are involved in fungicide sensitivity, in UOP226. Our results suggest that PuRV2 infection influences the ecology of G. ultimum in agricultural ecosystems where metalaxyl is applied. •The UOP226 isolate of Globisporangium ultimum is infected with the fusari-like virus PuRV1 and the toti-like virus PuRV2.•G. ultimum UOP226 was successfully cured from PuRV2 infection using hyphal tip isolation with high-temperature culture.•The metalaxyl sensitivity of UOP226 is higher than that of the PuRV2-free isogenic line.•Transcriptome analysis revealed downregulation of ABC-type transporter genes in UOP226.