Exposure to spaceflight enhances the virulence of Purpureocillium lilacinum against Tetranychus cinnabarinus: modulation of the host’s enzyme activities and microbiome

Multiple studies have been conducted to investigate the impact of space conditions on human, plant, and microbial life. This research investigated the virulence of spaceflight mutants of the entomopathogenic fungus Purpureocillium lilacinum (HP7, HP36, HP52) and its original strain (SP535) against Tetranychus cinnabarinus as well as examination of the T. cinnabarinus immune response, including alterations in enzyme profiles and microbiome composition post fungal application. Our observations revealed contrasting, time-specific differences in pathogenicity and tissue infection between the ground-based isolate and spaceflight mutant isolates. Analysis of detoxifying and antioxidant enzymes showed a significant reduction in enzyme activities T. cinnabarinus infected with the most virulent spaceflight mutants at 36 h post-fungal infection, compared to ground-based isolates. Additionally, the microbiota was reduced due to a fungal infection, partly due to decreased antioxidant enzyme activities. Our findings indicate that changes in the microbiota of T. cinnabarinus following infection with P. lilacinum (both ground-based and spaceflight mutant isolates) resulted in variations in metabolism and genetic information-related KEGG pathways. This data can help identify potential changes in the host immune system that drive increased virulence after spaceflight mutation.