A heat shock 70kDa protein MaltHSP70-2 contributes to thermal resistance in Monochamus alternatus (Coleoptera: Cerambycidae): quantification, localization, and functional analysis

Abstract

Background Heat Shock Proteins 70 (HSP70s) in insects act on a diverse range of substrates to assist with overcoming extreme high temperatures. MaltHSP70-2, a member of HSP70s, has been characterized to involve in the thermotolerance of Monochamus alternatus in vitro, while quantification and localization of MaltHSP70-2 in various tissues and its functional analysis in vivo remain unclear. Results In this study, temporal expression of MaltHSP70-2 indicated a long-last inductive effect on MaltHSP70-2 expression maintained 48 hours after heat shock. MaltHSP70-2 showed a global response to heat exposure which occurring in various tissues of both males and females. Particularly in the reproductive tissues, we further performed the quantification and localization of MaltHSP70-2 protein using Western Blot and Immunohistochemistry, suggesting that enriched MaltHSP70-2 in the testis (specifically in the primary spermatocyte) must be indispensable to protect the reproductive activities (e.g., spermatogenesis) against high temperatures. Furthermore, silencing MaltHSP70-2 markedly influenced the expression of other HSP genes and thermotolerance of adults in bioassays, which implied a possible interaction of MaltHSP70-2 with other HSP genes and its role in thermal resistance of M. alternatus adults. Conclusions These findings shed new insights into thermo-resistant mechanism of M. alternatus to cope with global warming from the perspective of HSP70s functions.

First evidence that interactions of Heat Shock Protein 20 with reproduction-related proteins aid in fertility recovering from heat stress in Monochamus alternatus

“…However, the molecular mechanisms underpinning this adaptive response remained to be elucidated. Our previous studies certi ed that the HSP20s contributed to the reproduction-related heat tolerance of M. alternatus (Li et al, 2022;Li et al, 2023). Building on these ndings, the present study aimed to identify the speci c substrate proteins interacting with MaltHSP20-5, which emerged as the most critical among these HSP20s, within the testes and ovaries.…”

“…The transcriptome data revealed that the gene number and up-regulation fold of HSPs are dominant after heat stress (Li et al, 2020). Subsequently, we found that six HSP70s and thirteen HSP20s were involved in the heat response of M. alternatus and possessed molecular high chaperone activity (Li et al, 2021;Li et al, 2022). More importantly, we innovatively discovered that one HSP20, MaltHSP20-5, accumulated in the ovary and testis and provide protection for reproductive processes under high temperature (Li et al, 2023).…”

“…A laboratory colony of M. alternatus was established from larvae collected from dead Pinus massoniana trees infested by B. xylophilus in Nanchang city, Jiangxi Province, China (28°50′45.6″N, 115°32′55.6″E) in Sep. 2021. A complete breeding system for M. alternatus in the laboratory was described in our previous study (Li et al, 2022).…”

Heat stress‐induced oviposition behavioral change correlates with sperm damage in the pine sawyer beetle, Monochamus alternatus

“…Adults were maintained in a 14 h:10 h, light:dark photoperiod, whereas eggs, larvae and pupae were reared in continuous darkness (0 h:24 h, light:dark). All life stages were kept at a constant temperature of 25 ± 0.5 °C and 70 ± 5% relative humidity (RH), in line with the methods described by Li et al 25…”

The pine sawyer beetle alters oviposition strategy in response to extreme high temperatures

“…The adults of M. alternatus used in this study were taken from a laboratory colony established from fourth-instar larvae collected from dead Pinus massoniana trees infested by B. xylophilus in Nanchang city, Jiangxi Province, China (28°50′45.6″N, 115°32′55.6″E) in Sep. 2020. The M. alternatus larvae, pupae, adults, and eggs were reared as previously described in a photoperiod of 14 hours light: 10 hours dark for adults and a photoperiod of 0 hour light:24 hours dark for eggs, larvae, and pupae at 25 ± 0.5°C with 70 ± 5% relative humidity (RH) (Li et al 2022).…”