Eyestalk transcriptome analysis reveals sexually dimorphic host-parasite interactions: divergent molecular strategies of sp. for reproductive and growth regulation in .

BACKGROUND

The Chinese mitten crab (), an economically critical migratory species inhabiting both freshwater and marine environments, is susceptible to parasitization by the rhizocephalan barnacle sp. in estuarine ecosystems. In this study, was found to be parasitized by sp. in the freshwater waters of the Anqing section of the Yangtze River, which manifested itself as restricted growth and development, hindered gonadal development, and apparent changes in sexual characteristics.

METHODS

Morphological analysis, serological testing, and eyestalk transcriptome analysis were conducted on male and female parasitized and non-parasitized crabs to investigate the molecular mechanisms by which sp. affects host growth and reproduction.

RESULTS

The study revealed that parasitized hosts of both sexes were significantly smaller than normal individuals and exhibited gonadal atrophy. Male hosts displayed feminization of secondary sexual characteristics, whereas females showed no significant alterations. Testosterone and ecdysterone levels decreased in male hosts, whereas estradiol levels declined in female hosts. Transcriptomic profiling revealed differentially expressed genes predominantly associated with metabolic processes, stimulus response, signal transduction, and reproduction. Thirteen key candidate genes related to parasite-induced suppression of host molting and growth, fourteen key candidate genes involved in male reproductive regulation, and ten candidate genes affecting female gonadal development were identified. Key genes involved in gonadal development-including , Dmrt family, cytochrome P450 family, , and exhibited sex-specific expression patterns. Additionally, critical growth-related genes such as , , and exhibited significant alterations in hosts of both sexes. sp. parasitism suppresses gonadal development and growth in both sexes, employing distinct regulatory strategies. It uses a "neuroendocrine disruption and reproductive gene regulation" strategy to regulate reproductive development in male hosts, while influencing female reproductive metabolism through a "Nutrient Hijacking-Hormonal Suppression" mechanism. Additionally, the parasitism disrupts host growth "molting inhibition". These findings elucidate the sex-specific metabolic, reproductive, and growth disruption strategies of sp., providing new insights into host-parasite interactions in decapod crustaceans.