The heat shock protein (Hsp) superfamily has received accumulated attention because it is ubiquitous and conserved in almost all living organisms and is involved in a wide spectrum of cellular responses against diverse environmental stresses. However, our knowledge about the Hsp co-chaperon network is still limited in non-model organisms. In this study, we provided the systematic analysis of 95 Hsp genes (LmHsps) in the genome of spotted sea bass (Lateolabrax maculatus), an important aquaculture species in China that can widely adapt to diverse salinities from fresh to sea water, and moderately adapt to high alkaline water. Through in silico analysis using transcriptome and genome database, we determined the expression profiles of LmHsps in response to salinity change and alkalinity stress in L. maculatus gills. The results revealed that LmHsps were sensitive in response to alkalinity stress, and the LmHsp40-70-90 members were more actively regulated than other LmHsps and may also be coordinately interacted as co-chaperons. This was in accordance with the fact that members of LmHsp40, LmHsp70, and LmHsp90 evolved more rapidly in L. maculatus than other teleost lineages with positively selected sites detected in their functional domains. Our results revealed the diverse and cooperated regulation of LmHsps under alkaline stress, which may have arisen through the functional divergence and adaptive recruitment of the Hsp40-70-90 co-chaperons and will provide vital insights for the development of L. maculatus cultivation in alkaline water.
Keywords: Lateolabrax maculatus; co-chaperon network; heat shock protein; molecular evolution; salinity-alkalinity adaptation.