The sweetpotato whitefly, Bemisia tabaci, is a vector of more than 100 plantdiseased viruses as well as a serious pest to various horticultural crops. Virus acquisition affects the vector’s development and reproduction, but its mechanism is largely unknown. Here we compared the temperature responses between non-viruliferous and TYLCV-viruliferous Q biotype of B. tabaci. When both non-viruliferous and viruliferous whiteflies were exposed for 1 and 3 h at 4, 25, and 35°C, the mortality rate of viruliferous whiteflies is higher than nonviruliferous after exposure at 4°C and 35°C, but no differences at 25°C between them. Analysis of the expression levels of heat shock protein (hsp) genes using the quantitative realtime PCR showed that viruliferous whiteflies has higher expression in hsp70, and hsp90 at both 4°C and 35°C, but no differences at 25°C. The results suggest that vector insects may not be durable to unfavorable temperature conditions when they acquisite plant viruses.

Heat shock p1'otein (Hsp) 40 acts as a co-cha perone of Hsp70 by fac ilitating the ATPase activity of Hsp70 as well as promoting the protein fo lding and rena turation by Hsp70. In the present study. Hsp40 gene was fu sed with a gene f’ragment encoding the HJV-l TAT protein transduction domain(YGRKKRRQRRR) in a bacterial exp1' ession vector pTAT-HA to produce the TAT-fused Hsp40(TAT- Hsp40). Purified TAT-Hsp40 was effectively t 1'ansduced into the HEK 293 cells in a time- and dose-dependent manne1' To examine the effec t of TAT- Hsp40 upon oxidalive stress, HEK293 cells were exposed to H2Û2. Oxidative stress induced the ra pid increase of proteasome activity foll owed by celJ death in HEK 293 cells However ‘ HEK 293 cells t 1'ansduced by TAT- Hsp40 showed r esistance against oxidative st 1'ess induced cytot oxicity, TAT- Hsp40 transduced cell s showed dec1'eased p1'oteasome activity and inhibi ted Hs p70 degradation. These results suggest that Hs p40 rnight protect cell death f rom oxida tive st1'ess by p1'ese1'ving the cellula1' level of Hs p70.