Transcriptional Response of Salinity Stress in Red Claw Crab Uca arcuata

Bing Wang ¹ Shaolei Sun ¹ Feijun Zhang ² Zhiqiang Han ^1*

• ¹ Zhejiang Ocean University, Zhoushan, China
• ² Zhoushan Marine Workstation, East China Sea Branch of State Oceanic Administration, zhoushan, China

The red claw crab, Uca arcuata, is a globally distributed intertidal species inhabiting saline ecosystems. Despite its ecological significance, few studies have explored its molecular adaptations to salinity stress, including functional genes and regulatory pathways. In this study, we performed RNA sequencing on U. arcuata gill tissues exposed to salinity gradients (15‰, 25‰ control, and 35‰) to profile transcriptional responses. A total of 63.83 GB of high-quality clean reads were generated, yielding 125,462 unigenes with robust assembly metrics (N50 = 969 bp; mean length = 688 bp). Among these, 33,936 unigenes (33.51%) were functionally annotated, and transcriptome analysis predicted 101,280 coding sequences (CDSs) and 52,706 simple sequence repeats (SSRs). Compared with the control group, the high-salinity group had 52 differentially expressed genes (DEGs), with 36 upregulated and 16 downregulated genes. The low-salinity group obtained 1035 DEGs, with 780 upregulated and 255 downregulated genes. GO enrichment analysis results showed a significant enrichment of DEGs in signal transduction, enzymatic activity, and binding. KEGG enrichment analysis showed that most DEGs were associated with signaling pathways and metabolism. APOA1, APOA2, GPX and GST were specific genes related to salinity adaptation. Five DEGs were randomly selected for quantitative RT-PCR validation. Results demonstrated that the transcriptome data are highly reliable, thus laying a certain foundation for studying the regulatory mechanism of U. arcuata under salinity stress. Such mechanism is beneficial for the conservation and utilization of U. arcuata resources in global climate change.