Cassie Ettinger, Ph.D.

Recently wide-spread insecticide resistance has been detected in populations of GWSS in the southern portions of California’s Central Valley. In order to better understand potential mechanisms of resistance, we profiled wild-caught insecticide-resistant and relatively susceptible GWSS transcriptomes. We identified 81 differentially expressed genes with higher expression in resistant individuals, including a highly expressed cytochrome P450 gene with similarity to CYP6A9 that might be a good target for mitigation efforts. We also observed an over-enrichment of GO terms representing functions supportive of roles in resistance mechanisms (cytochrome P450s, M13 peptidases, and cuticle structural proteins).

While studies have focused on bacterial pathogens or known symbionts of GWSS, little work has been done at the scale of the microbiome (the bacterial community) or mycobiome (the fungal community). We characterized the mycobiome and the microbiome of GWSS across Southern California and explored correlations with captivity and host insecticide resistance status. We found that while the GWSS mycobiome significantly varied across Southern California, the microbiome did not. We also observed a significant difference in both the mycobiome and microbiome between captive and wild GWSS. Finally, we found that the mycobiome, but not the microbiome, was correlated with insecticide resistance status in wild GWSS. Future work should explore the putative link between microbes and insecticide resistance status and investigate whether microbial communities should be considered in GWSS management practices.