Upregulation of hepatopancreas associated lectin transcripts in Macrobrachium rosenbergii in response to Vibrio harveyi and M. rosenbergii nodavirus (MrNV)

Abstract

Aim: The giant fresh water prawn, Macrobrachium rosenbergii is widely cultured in semi-intensive farming systems for commercial production. However, the major constraint to sustainable production practices include diseases due to bacterial and viral infections. The immunity related genes contribute towards prawn health by regulating the expression of antimicrobial peptides and promoting phagocytosis. In this study, we examined the expression of Mr(T)Lec4 and Mr(T)Lec2 associated with the hepatopancreas tissue of M. rosenbergii adults after challenge with Vibrio harveyi and M. rosenbergii nodavirus (MrNV). Methodology: The transcript sequences were derived from the M. rosenbergii transcriptome database. Gene-specific primers were designed for qRT-PCR analysis of tissue-specific expression patterns of Mr(T) Lec4 and Mr(T) Lec2 in M. rosenbergii. Subsequently, the temporal expression of transcripts were examined in the hepatopancreas tissue following challenge of the adult prawn with bacteria V. harveyi and M. rosenbergii nodavirus (MrNV). The MrNV positive inoculum used for challenge experiments were obtained from infected post-larval stages of the prawn. Results: The relative expression of Mr(T) Lec4 and Mr(T) Lec2 in the hepatopancreas showed an increase of about 23 and 28-folds, respectively, compared with other tissues. At post-V. harveyi challenge, the mRNA levels of Mr(T) Lec4 in hepatopancreas was upregulated at 6 hr. Further, the expression pattern of Mr(T) Lec4 and Mr(T) Lec2 in hepatopancreas tissue at different time points in response to MrNV challenge was analyzed by qRT-PCR. Both the transcripts showed upregulation at 48 hrs post-challenge confirming induction after MrNV challenge. Interpretation: This study for the first time reports involvement of hepatopancreas-associated lectin to V. harveyi and MrNV challenge. A direction towards its putative role in regulation of immune response of M. rosenbergii is been currently investigated using RNA interference and expression studies.