Silencing of prophenoloxidase (proPO) gene in freshwater prawn, Macrobrachium rosenbergii, makes them susceptible to white spot syndrome virus (WSSV)

Abstract

Prophenoloxidase (proPO) is very important to protect the invertebrates from microbial infections. Our previous studies revealed that proPO was up‐regulated in WSSV‐injected Macrobrachium rosenbergii and is responsible for protecting M. rosenbergii from WSSV. In order to prove this mechanism, an attempt was made in the present study to silence the proPO gene in freshwater prawn by injection of dsRNA‐proPO followed by WSSV challenge. Two partial fragments of proPO with the size of 251 and 331 bp were used to synthesize dsRNA using LITMUS38i vector and E. coli. The bacterially synthesized dsRNA‐proPO was used to silence proPO gene to determine its involvement in developing resistance in prawn against WSSV. In proPO gene‐silenced prawn, 100% mortality was observed after WSSV challenge whereas no mortality was observed in prawn injected with WSSV alone. The WSSV infection in gene‐silenced prawn was confirmed by PCR, and its propagation was quantified by ELISA and real‐time PCR at different time intervals. Real‐time PCR assay revealed a significant reduction in the expression of proPO gene in WSSV‐challenged proPO‐silenced prawn when compared to normal prawn. Level of proPO was reduced significantly in the haemolymph of proPO‐silenced prawn when compared to prawn injected with PBS.

Effects of PmDOME and PmSTAT knockdown on white spot syndrome virus infection in Penaeus monodon

“…For example, in red swamp crayfish Procambarus clarkia , injection with the recombinant proPO2 could significantly decrease 65% mortality of WSSV-infected crayfish and reduced the amount of WSSV copy number in hepatopancreas and gill 28 . In addition, the silencing of the proPO gene in freshwater prawn Macrobrachium rosenbergi makes them susceptible to WSSV 29 . It was reported that the proPO gene was highly up-regulated after LPS stimulation, while the lack of LvSTAT down-regulated the proPO expression.…”

Dietary thiamine requirement of Pacific white shrimp, Litopenaeus vannamei

“…Results in the present study convey that optimum dietary thiamine levels signi cantly in uenced the activity of PO. In a study byThamizhvanan et al (2021), proPO gene-silenced freshwater prawn (Macrobrachium rosenbergii) showed 100% mortality in a challenge test exposing them to white spot syndrome virus (WSSV), while no mortality was observed in non-genetically modi ed shrimps injected with WSSV alone. It appears; therefore, the PO system is…”