Identification and Characterization of Three Heat Shock Protein 90 (Hsp90) Homologs in the Brown Planthopper

Abstract

Hsp90 (heat shock protein 90) chaperone machinery is considered to be a key regulator of proteostasis under both physiological and stress growth conditions in eukaryotic cells. The high conservation of both the sequence and function of Hsp90 allows for the utilization of various species to explore new phenotypes and mechanisms. In this study, three Hsp90 homologs were identified in the brown planthopper (BPH), Nilaparvata lugens: cytosolic NlHsp90, endoplasmic reticulum (ER) NlGRP94 and mitochondrial NlTRAP1. Sequence analysis and phylogenetic construction showed that these proteins belonged to distinct classes consistent with the predicted localization and suggested an evolutionary relationship between NlTRAP1 and bacterial HtpG (high-temperature protein G). Temporospatial expression analyses showed that NlHsp90 was inducible under heat stress throughout the developmental stage, while NlGRP94 was only induced at the egg stage. All three genes had a significantly high transcript level in the ovary. The RNA interference-mediated knockdown of NlHsp90 its essential role in nymph development and oogenesis under physiological conditions. NlGRP94 was also required during the early developmental stage and played a crucial role in oogenesis, fecundity and late embryogenesis. Notably, we first found that NlHsp90 and NlGRP94 were likely involved in the cuticle structure of female BPH. Together, our research revealed multifunctional roles of Hsp90s in the BPH.

ArHsp90 is important in stress tolerance and embryo development of the brine shrimp, Artemia franciscana

“…Previous researches listed the pleiotropic roles of cytosolic Hsp90s in embryogenesis and postembryonic development in insects including fruit fly, red flour beetle, and brown planthopper. 45 , 46 , 44 The finding in A. franciscana is consistent with these researches and further extends the role of Hsp90 in the embryo and postembryonic development to primitive arthropods.…”

“… 48 , 52 , 53 And in most cases, cytosolic Hsp90 is functional against heat stress in insects. 54 , 44 , 55 In addition to the mentioned findings, the results generated in this study using RNAi indicate that ArHsp90 has an important protective role during stress in A. franciscana nauplii, either by protecting proteins from irreversible denaturation or assisting in their refolding or degradation. The exact amount of ArHsp90 under normal and stress conditions was not evaluated in this study but could be determined in the future in order to more fully characterize the role of ArHsp90 in the stress tolerance of A. franciscana nauplii.…”

Threshold‐dependent gene regulation and partial assortative mating determine wing dimorphism of an insect

“…The threshold‐dependent response of wing development genes may be more sensitive to the environmental changes. The brown planthoppers are responsive to insecticides and heat stress in gene expression levels (Yang et al 2019, Chen et al 2020), which enhances the adaptability to environment stress. The expression level threshold‐dependent gene regulation of wing morphs may make the shift between long‐ and short‐winged morphs more flexible according to environmental cues and maintain wing dimorphism.…”