Isolation of the C-type lectin like-domain cDNAs from the mud crab Scylla paramamosain Estampador, 1949, and its expression profiles in various tissues, during larval development, and under Vibrio challenge

Scylla paramamosain Estampador, 1949 is one of the most precious marine crabs farmed in China. The crab is prone to infection by microbes at various stages during its growth, leading to high mortality. C-type lectin has a characteristic carbohydrate recognition domain and plays an important role in the immunity system. A cDNA library from the mud crab S. paramamosain was constructed using the SMART technique. Two complete cDNA sequences showing high identities with the C-type lectin gene were isolated from the library. The two full-length C-type lectin cDNAs of S. paramamosain (SpLec1 and SpLec2) consist of 746 and 834 bp, respectively. Quantitative realtime PCR analyses revealed that the C-type lectins were expressed mainly in haemocytes, muscle and hepatopancreas, with the highest expression level found in hepatopancreas. The C-type lectin mRNA expression in continuous developmental stages during zoeal phases were also examined by quantitative real-time PCR. After infection with Vibrio parahaemolyticus (Sakazaki, 1963) at a concentration of 2.3 × 10 6 cfu/ml, the temporal expression of SpLec1 and SpLec2 mRNA in the megalopa stage was first increased, reached a maximum, and then dropped to the original level again. The research of C-type lectins in Scylla paramamosain could shed new light on studies on immunity and moulting in the mud crab.