Identification and Verification of the Blue Pigment in the Edible Jellyfish (Rhopilema esculentum)

Abstract

Rhopilema esculentum is widely cultured in Chinese coastal regions and has thousand years of consumption history in China. Despite R. esculentum owns multiple colors (mainly ochre and blue) in aquaculture ponds, little is known about the pigments and color formation. This study identified and verified the blue pigment of R. esculentum. Results showed that the blue pigment of R. esculentum has 262 amino acids with 54.96% identity to the blue pigment protein precursor of Rhizostoma pulmo. The blue pigment of R. esculentum has Kringle and Frizzled domains, which is in accordance with rhizostomins characteristics. Compared to ochre R. esculentum, the expression level of blue pigment increased 3.49-fold in blue R. esculentum. In addition, overexpression of the blue pigment in Rhodosporidium toruloides made transformant cells blue under blue light excitation. Our findings provide knowledge for the blue color formation of R. esculentum and will benefit the color selection of R. esculentum with excellent traits.