| Abstrakt: |
The reproductive function of insects has long been recognized to be especially sensitive to heat. The successful colonization and outbreak of Monochamus alternatus (Coleoptera: Cerambycidae), a dominant insect vector of destructive pine wilt disease, is strongly associated with its reproductive fitness under high temperature. Heat shock protein 20s (HSP20s) confer resistance against high temperature to insects, but little is known about the molecular functions of HSP20s in protecting reproductive processes. Here, 13 hsp20s of M. alternatus were characterized. These sequences had conserved domains, gene structures, and phylogenetic relationships, but varied in subcellular localization. All sequences were induced by high temperature from 35 to 45°C lasting 3 h, and most MaltHSP20s reached a peak in transcript abundance at 42.5°C. MaltHSP20 transcripts and proteins were highest in the ovary or testis under either normal or high temperatures. Furthermore, immunofluorescence assays in reproductive tissues suggested that MaltHSP20-5 protein accumulated in the primary spermatocytes and nurse cells under normal circumstances, while it significantly increased in both the cytoplasm and nuclei after heat treatment. Thermal aggregation assays suggested that the MaltHSP20-5 protein possessed high chaperone activity in vitro. Furthermore, silencing of MaltHSP20-5 reduced the reproductive fitness under high temperature. Overall, these findings establish that the HSP20 family is involved in the heat tolerance of M. alternatus, and HSP20 accumulation in the ovary and testis might provide protection for reproductive processes under high temperature. [ABSTRACT FROM AUTHOR] |
