Transcriptome and proteome reveal abnormal spermatozoa in precocious Chinese mitten crab, Eriocheir sinensis

In juvenile Chinese mitten crabs, Eriocheir sinensis, the occurrence of sexual gland maturation in the first year is known as precocity and significantly affects culture productivity and profitability. The miniaturization of in-dividuals is a key characteristic of precocious crabs. Most related studies focus on the underlying causes, nutritional quality, biochemical components and differentially expressed mRNAs of precocious crab individuals and tissues. The reproductive performance of precocious crabs is evaluated based on offspring quality. However, the status of precocious parental gametes (especially spermatozoa) directly related to the offspring has not been reported. To clarify the differences in spermatozoa between precocious and normal mature crabs, spermatozoal transcriptome and proteome data were obtained via high-throughput sequencing technology. The results revealed a total of 856 differentially expressed genes and 150 differentially expressed proteins in spermatozoa. Functional analysis showed that these genes and proteins identified in the spermatozoa of precocious E. sinensis were significantly enriched in the categories of substance and energy metabolism. And more, the miniaturization of spermatogenic cells was also identified in precocious crabs. This indicates that metabolic disorders might be the main reason for the miniaturization of spermatogenic cells in precocious E. sinensis males. The molecular defects in precocious sperm were closely related to the imbalances in essential substance and energy metabolism. These findings provide foundational information and insights into hidden biological irregularities associated with precocious phenotypes and will contribute to the further study of precocious E. sinensis males and even other crustaceans.

Automated summary

Differential gene and protein expression in spermatozoa of precocious E. sinensis suggest metabolic disorders as main reason for miniaturization of spermatogenic cells, shedding light on hidden biological irregularities associated with precocious phenotypes.