Recent development in ecdysone receptor of crustaceans: current knowledge and future applications in crustacean aquaculture

Abstract

Ecdysone receptor (EcR) is the primary regulator of the ecdysteroid signalling pathway, a critical pathway that directly links to moulting. In addition, EcR also regulates growth, development, reproduction and regeneration in crustaceans. However, there remains a huge gap of knowledge between the detailed structure and functional role(s) of crustacean EcR compared to that of insects. Motif and phylogenetic analyses of publicly available crustacean EcR proteins revealed the evolutionary relationship of EcR in this subphylum and highlighted its conserved characteristics among crustaceans. The role of EcR in the regulation of essential physiological processes in crustaceans including moulting, chitin synthesis, general growth and development, gonadal and maturation, and limb regeneration was discussed based on the available literature. This essential moult-related nuclear receptor could serve as a useful molecular indicator of moulting and gonadal maturation, as a potential target for pesticide production against parasitic crustacean species in the aquaculture industry, as well as valuable bioindicators of environmental stressors.

Dietary cholesterol promotes growth and ecdysone signalling pathway by modulating cholesterol transport in swimming crabs (Portunus trituberculatus)

“…Molting, a fundamental process for growth in crustaceans, is positively and negatively regulated by various type of hormones. Molting begins with multiple steps converting cholesterol to the steroid hormone, ecdysone in the Y-organ ( Abdullah-Zawawi et al., 2021 ). The molt-promoting function of ecdysone is achieved via the ecdysone signalling pathway to increase expression of downstream genes.…”

“…In addition to ecdysone, MF in mandibular organ, is another hormone regulating molting in crustaceans also modulated by cholesterol level ( Kumar et al., 2018 ; Abdullah-Zawawi et al., 2021 ). The mechanism by which MF regulates molting is still unclear and one study reported that ecdysone and MF interact to coordinate the molt cycle through regulation of EcR/RXR ( Hyde et al., 2019 ).…”

“…Ecdysone, the major ecdysteroid produced is converted to the active form, 20-hydroxyecdysone (20E), that is dominant in mediating the changes of the ecdysis process, which is regulated by intricate multi-hormonal system ( Chang and Mykles, 2011 ). Furthermore, 20E activates the ecdysone receptor (EcR)/retinoid-x receptor (RXR) complex, that promotes a series of downstream events including up-regulation of several genes related to processes involved in molting regulation, such as the biosynthesis and degradation of chitin, osmotic flux and cuticle release ( Abdullah-Zawawi et al., 2021 ). In addition to ecdysteroids, 2 neuropeptides including molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH) are involved in molting and inhibit ecdysone synthesis in the Y-organ ( Chung and Webster, 2003 ; Techa and Chung, 2015 ).…”

Early-Stage Defense Mechanism of the Cotton Aphid Aphis gossypii Against Infection With the Insect-Killing Fungus Beauveria bassiana JEF-544

“…When ecdysone is oxidized by CYP314A1, it becomes 20-hydroxyecdysone (20HE), an activated form. 20HE acts as a transcription factor by binding to the ecdysone receptor (EcR) in the nucleus and secretes ETH ( 48 – 50 ). ETH increases the release of EH as a positive feedback, and EH stimulates the secretion of CCAP ( 51 ).…”

Moult induction methods in soft‐shell crab production

“…Ecdysteroids are commonly found in two forms, that is the inactive ecdysone (prohormone) and the physiologically active form 20‐hydroxyecdysone (20E) which is activated in the peripheral tissues (Hyun, 2018). Generally, 20E and ecdysone concentrations are low during intermoult, highest during premoult and decrease again during postmoult (Abdullah‐Zawawi et al, 2021; Styrishave et al, 2004; Thomton et al, 2006). Apart from 20E, another active form of ecdysteroid, that is ponasterone A (PoA), exists in some crustacean species.…”