Conditional effects of Cardinium on microbiota in an invasive whitefly under different ecological factors

Cardinium, a vital symbiont in Bemisia tabaci Mediterranean (MED), can influence the microbiota in B. tabaci MED under high temperatures. However, the effects of Cardinium infection on the microbiota in B. tabaci MED with different genetic backgrounds under different ecological factors still remain poorly understood. In this study, based on full-length 16S rRNA gene sequencing and quantitative PCR (qPCR) experiments, the effects of Cardinium infection on the microbiota in two B. tabaci MED geographical populations with different genetic backgrounds were determined with particular attention to ecological factors such as high-temperature treatment and host-plant switching. Results indicated that high temperature treatment and host-plant switching affected the symbiont titer, microbiota diversity, and function differently in the two populations, highlighting the genetic background. The present study also revealed that the increase of Cardinium titer would significantly change the response of the microbiota function of the Cardinium-infected line compared to the uninfected line, while the decrease and immutability of Cardinium titer would not, which indicates that the Cardinium titer may be closely associated with the microbiota function in whitefly. Overall, the genetic background of whiteflies influences microbiota response under high temperatures and host-plant changes, and Cardinium titer significantly impacts microbiota function. These findings enhance understanding of the complex relationships among symbionts, microbiota, and host insects.IMPORTANCEThis study sheds light on how genetic differences in Bemisia tabaci Mediterranean (MED) populations influence their microbiota's response to environmental stressors like high temperatures and host-plant changes. By focusing on the role of Cardinium-a key symbiont-the research reveals its significant impact on microbiota diversity and function, particularly when its titer increases. The findings emphasize the interplay between genetic background, symbiont levels, and microbiota, advancing our understanding of the ecological adaptability of these insects. This knowledge is vital for developing better pest management strategies and predicting responses to environmental changes.