Functional analysis of a novel orthologous small heat shock protein (shsp) hsp21.8a and seven species-specific shsps in Tribolium castaneum

Highlights

• Firstly identified another novel orthologous cluster of sHSPs in insects.

• Two shsps were identified in Acrythociphon pisum and one new shsp was found in Anopheles gambiae.

• Novel orthologous Tchsp21.8a in Tribolium castaneum had typical features of orthologous shsps.

• Most species-specific Tcshsps were related to anti-heat stress by hundreds-fold up-regulation.

• Species-specific Tcshsps did not respond to cold but had different responses under other stresses.

Abstract

Small heat shock proteins (sHSPs) are important modulators of insect survival. Previous research revealed that there is only one orthologous cluster of shsps in insects. Here, we identified another novel orthologous cluster of shsps in insects by comparative analysis. Multiple stress experiments and function investigation of Tchsp21.8a belonging to this orthologous cluster and seven species-specific shsps were performed in the stored-grain pest Tribolium castaneum. The results indicated that expression of Tchsp21.8a showed weak responses to different stresses. However, expressions of most species-specific shsps exhibited hyper-responses to heat stress, and expressions of all species-specific shsps displayed diverse responses during other stresses to protect beetles in a cooperative manner. Additionally, Tchsp21.8a and species-specific Tcshsp19.7 played important roles in the development of T. castaneum, and all Tcshsps had a certain impact on the fecundity. Our work created a comprehensive reliable scaffold of insect shsps that can further provide instructive insights to pest bio-control