Identification of differentially expressed genes and signalling pathways to elucidate molecular mechanisms underlying growth differences among the male morphotypes ofMacrobrachium rosenbergii

The giant freshwater prawn (GFP)Macrobrachium rosenbergiiis an economically important aquaculture species in China. In culture, it is common for males to show unique morphotypes, which exhibit distinct heterogenous individual growth. Little information is currently available on the molecular mechanisms underlying growth differences among male morphotypes of GFPs. Thus, we herein aimed to identify key genes and signalling pathways to elucidate molecular mechanisms underlying growth differences among the male morphotypes of GFPs. We performed transcriptome analyses using RNA-Seq to compare the following male morphotypes of GFPs: orange claw males, old blue claw males and small males. In total, 97.44 Gb clean data were obtained, and 1,857,760 unigenes were annotated by alignment with public protein databases. Moreover, we found 2,072 and 22,431 differentially expressed genes (DEGs) from the eyestalk and gonads respectively. Gene ontology analyses revealed that 'system process' and 'multicellular organismal process' were the most enriched in the eyestalk and gonad tissue samples respectively. Furthermore, Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that pathways associated with gene regulation may play a key role in GFP growth. To summarize, this study provides a valuable repository of novel transcripts for various male morphotypes of GFPs and gives further insights into the molecular mechanisms underlying growth differences in GFPs, which should promote the breeding of commercially cultivated GFPs.