Magnaporthe oryzae, the causal agent of rice blast disease, produces devastating damage to global rice production. It is urgent to explore novel strategies to overcome the losses caused by this disease. 9-phenanthrol is often used as a transient receptor potential melastatin 4 (TRPM4) channel inhibitor for animals, but we found its fungal toxicity to M. oryzae. Thus, we explored the antimicrobial mechanism through transcriptome and metabolome analyses. Moreover, we found that overexpression of a gene encoding 4-hydroxyphenylpyruvate dioxygenase involved in the tyrosine degradative pathway enhanced the tolerance of 9-phenanthrol in M. oryzae. Thus, our results highlight the potential fungal toxicity mechanism of 9-phenanthrol at metabolic and transcriptomic levels and identify a gene involving 9-phenanthrol alleviation. Importantly, our results demonstrate the novel mechanism of 9-phenanthrol on fungal toxicity that will provide new insights of 9-phenanthrol for application on other organisms.

Heavy metals are used for fungicides as they target phytopathogen in multiple ways. Magnaporthe oryzae is the most destructive rice pathogen and is threatening global rice production. In the eukaryotes, the regulation mechanisms of Mn homeostasis often focus on the posttranslation, there were a few results about regulation at transcript level.

Plants growing in open environments are frequently coinfected by multiple strains of the same pathogen. However, few investigations have been carried out to reveal the outcomes and underlying mechanisms of such infections. This study aimed to observe the behaviors of two different strains under coinfection and cocultivation. We constructed an experimental system to study such interactions directly by labeling Magnaporthe oryzae strains with the green fluorescent proteins and mushroom cherry fluorescent protein to observe mixed strain behavior in vivo and in vitro. Moreover, multiomics analyses were conducted to explore the underlying mechanisms at the genomic, transcriptomic, and metabolomic levels. Our results revealed that coinfection with two strains can affect disease severity and that the more weakly virulent strain benefits from the coinfection system. We also found that amino acid variation might negatively influence such interactions at transcriptomic and metabolomic levels. In addition, we showed that the overexpression of a glutamine-related gene improved strain competitiveness during mixture cultivation. Collectively, our results provided experimental methods to analyze the interaction between two strains of M. oryzae and preliminarily explored the interacted mechanism of two strains under cocultivation through multiomics analyses.