Cloning, Identification, and Functional Analysis of the Gene in .

is the most widely distributed freshwater shrimp in China, with important economic value and great potential for development. The forkheadboxL2 () gene has been found to be involved in the reproductive development of many crustaceans. To understand the role of the gene in the gonad development of , we designed CDS-specific primers for the () gene and cloned its CDS sequence using RT-PCR. The nucleotide and protein sequence information was then analyzed through bioinformatics analysis. The expression and subcellular localization of in various tissues were detected using qRT-PCR and in situ hybridization. The effects of knockdown on gonad development were investigated using RNA interference. The results showed that the CDS length of the gene was 1614 bp and encoded 537 amino acids. Protein sequence comparison and phylogenetic analysis showed that was the closest relative to Crayfish. qRT-PCR analysis indicated that the expression level of in the testis was significantly higher (>40 fold) than that in the ovary ( < 0.01). The in situ hybridization results showed that was expressed in both the cytoplasm and the nucleus of egg cells, and that the expression was strongest in egg cells at the early stage of yolk synthesis, while weak in the secondary oocytes. The positive signal was strongest in the spermatocyte nucleolus, while only a trace signal was observed in the cytoplasm. After interfering with the gene using dsRNA, the expression of in the RNA interference group was significantly lower than that in the control group, and this interference effect lasted for one week. Moreover, the gonad index of the experimental group was significantly lower than that of the control group ( < 0.05) after 10 days of cultivation following knockdown. The expression levels of the and genes, which are related to gonad development, decreased significantly after gene interference. The results suggest that the gene is involved in the growth and development of gonads, particularly in the development of testis, and is related to the early development of oocytes. This study provides a theoretical basis for the artificial breeding of .