Dietary exposure to Cry1Fa protein can lower microbiome biodiversity and induce shift in symbiotic microbial communities in wolf spider Pardosa astrigera.

Pardosa astrigera wolf spiders are important natural enemies of insect pests in cotton fields. Genetically modified (GM) crops expressing Bacillus thuringiensis (Bt) Cry proteins - toxic to target insect pests - are increasingly cultivated for insect pest management. To evaluate the potential negative effects of Bt-GM crops on beneficial non-target organisms, we assessed the effect of the Cry1Fa protein on P. astrigera, including on its symbiotic microbial communities. No adverse effects were detected on the survival rate and body weight of P. astrigera during growth and development. However, P. astrigera adult microbiome exhibited a reduced diversity as well as a shift in the microbial community structure. The dominant bacterial phyla in P. astrigera shifted from Actinobacteria to Firmicutes after feeding on prey enriched in Cry1Fa protein. Furthermore, Bacillus became the most abundant genus in P. astrigera females, while the dominant genus (Corynebacterium_1) in P. astrigera males did not change. Both males and females exhibited lower abundances of Wolbachia after feeding on Cry1Fa-contaminated prey. Overall, consuming Cry1Fa-contaminated prey changed the microbial community in P. astrigera, with higher impact in female microbiome. These findings provide new insights for environmental safety assessments of GM crops and to understand the importance of the potential effects of GM crops on microbiota of non-target organisms of importance for biocontrol ecosystem services. [ABSTRACT FROM AUTHOR]