Genome-Wide Identification and Analysis of the Heat-Shock Protein Gene Superfamily in Bemisia tabaci and Expression Pattern Analysis under Heat Shock.

The thermal tolerance of Bemisia tabaci MED, an invasive whitefly species with worldwide distribution, plays an important role in its ecological adaptation during the invasion process. Heat-shock proteins (HSPs) are closely related to heat resistance. In this study, 33 Hsp s ( BtaHsp s) were identified based on sequenced genome of B. tabaci MED belonging to six HSP families, among which 22 Hsp s were newly identified. The secondary structures of a further 22 BtaHsp s were also predicted. The results of RT-qPCR showed that heat shock could affect the expression of 14 of the 22 Hsp s newly identified in this study. Among them, the expression level of six Hsp s increased under 42 °C treatment. As the unstudied gene, BtaHsp90A3 had the highest increase rate. Therefore, BtaHsp90A3 was chosen for the RNAi test, and silencing BtaHsp90A3 by RNAi decreased the survival rate of adult B. tabaci at 42 °C. The results indicated that only a few Hsp s were involved in the thermal tolerance of host whitefly although many Hsp s would response under heat stress. This study conducted a more in-depth and comprehensive identification that demonstrates the evolutionary relationship of BtaHsp s and illustrates the response of BtaHsp s under the influence of thermal stress in B. tabaci MED.