| Summary: | High temperature tends to be a contributing factor to the spread of vector-borne viral diseases by enhancing vector
competence. However, the underlying mechanisms of the increased virus transmission capacity of vectors under heat
stress are still largely unknown. Tomato yellow leaf curl virus (TYLCV) is one of the most devastating plant DNA
viruses worldwide and is transmitted exclusively by Bemisia tabaci. Here, we identified heat shock factor (HSF) as a key
transcription factor that mediates TYLCV accumulation in whitefly vectors under heat stress. Quantitative analysis
revealed that the amount of TYLCV DNA in whiteflies gradually increased with increasing temperature (above 38 °C).
To determine the underlying mechanism, RNA-seq analysis was performed, which revealed that 1 h of heat stress
caused a dramatic increase in heat shock protein (HSP) expression. Moreover, the whitefly HSP transcription factor
HSF was shown to specifically interact with the intergenic region of TYLCV via yeast one-hybrid and dual-luciferase
analyses. Additionally, the transcriptional activity of HSF gradually increased with increasing heat treatment tempera‑
ture, indicating a similar pattern of virus accumulation under heat stress. Knocking down HSF in whiteflies caused
a significant decrease in TYLCV DNA and coat protein. Our results reveal the important role of HSF in mediating virus
accumulation in insect vectors under high temperature and provide insights into how environmental factors affect
plant virus‒vector interactions.
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