Screening of morphology-related genes based on predator-induced transcriptome sequencing and the functional analysis of gene in .

High fish predation pressure can trigger "induced defense" in species, resulting in phenotypic plasticity in morphology, behavior, or life-history traits. The molecular mechanisms of defense morphogenesis (e.g., the tail spine and helmet) in remain unclear. In the present study, the tail spine, helmet, and body of under fish and non-fish kairomones conditions were collected for transcriptome analysis. A total of 24 candidate genes related to the morphological defense of were identified, including 2 trypsin, one cuticle protein, 1 C1qDC protein, and 2 ferritin genes. The function of the gene ( cuticle protein gene) in relation to tail spine morphology was assessed using RNA interference (RNAi). Compared with the EGFP (Enhanced green fluorescent protein) treatment, after RNAi, the expression levels of the gene ( cuticle protein gene) showed a significant decrease. Correspondingly, the tail spines of the offspring produced by after RNAi of the gene appeared curved during the experiment. In whole-mount in situ hybridization, a clear signal site was detected on the tail spine of before RNAi which disappeared after RNAi. Our results suggest that the gene may play an important role in tail spine formation of , and will provide a theoretical basis for studying the molecular mechanisms of the morphological plasticity in cladocera in the future.