Composition and expression of heat shock proteins in an invasive pest, the rice water weevil (Coleoptera : Curculionidae)

For poikilothermic groups such as insects, the capacity to adapt to different temperature regimes is particularly important for survival. To investigate the possible role of heat shock proteins (Hsps) in the invasive pest, the rice water weevil (Lissorhoptrus oryzophilus Kuschel, Coleoptera: Curculionidae), we first analyzed the composition and expression profile of Hsp families under sub-lethal temperatures of 0 °C and 43 °C, using the quantitative realtime polymerase chain reaction. Eight genes coding Hsp90, Hsp70, and small Hsps were upregulated under heat stress, while only 1 Hsp70 gene and 1 Hsp90 gene were up-regulated under cold stress. Results indicate that Hsps from all families except Hsp60 are responsible for the capacity of L. oryzophilus to tolerate temperature stress, although more genes were up-regulated, and more rapidly, under heat stress than under cold stress. Secondly Hsp expression patterns in diapausing and non-diapausing female adults were investigated. The results showed that rice water weevils in diapause up-regulated no Hsp gene but they downregulated 4 small Hsps, 2 Hsp90, 1 Hsp70 and 1 Hsp60 genes.