Gamma irradiation and heat exposure generate temperature-responsive microbiota shifts in predatory mite Phytoseiulus persimilis (Mesostigmata: Phytoseiidae)

The growing urgency of climate change, particularly the rising frequency and severity of extreme heat events, has spotlighted the need for the thermal resilience of natural enemy in pest management. To understand the plasticity of predatory mite in response to thermal adaptation, 3 irradiated strains of Phytoseiulus persimilis Athias-Henriot were induced by Cobalt-60 gamma rays to evaluate the thermotolerance. We integrated both DNA- and RNA-based 16S rRNA gene sequencing to explore whether irradiation and heat stress could impact the microbiome of the predatory mites. Our findings revealed that irradiation enhanced the heat tolerance of predatory mites without compromising fecundity or predation efficiency. Unexpectedly, irradiation had minimal impacts on overall microbial diversity, whereas RNA-based 16S rRNA gene sequencing unveiled irradiation strain-specific enrichment of stress-responsive taxa (e.g., Bacillus sp.), while no such specific enrichment was observed at the DNA level. Furthermore, heat stress significantly restructured the microbiome of P. persimilis, particularly enriching Limnobacter thiooxidans. Methodologically, the DNA/RNA microbial profiles highlighted divergent functional partitioning: Gammaproteobacteria dominated at DNA level, while transcriptionally active Actinobacteria prevailed in RNA level. In conclusion, these results establish a "host-microbiota co-regulation" paradigm for resistance breeding, offering a sustainable pathway to reinforce biological control systems against global warming challenges.