title: Gene silencing of VP9 gene impairs WSSV infectivity on Macrobrachium rosenbergii.
abstract: White Spot Syndrome Virus (WSSV) remains the most widespread and devastating infectious agent that hit the shrimp aquaculture industry worldwide. To date, there are no known effective strategies yet to combat WSSV infection. Hence, functional studies on genes critical for viral infection is essential in elucidating shrimp-virus interaction. Here we report the function of a gene from WSSV coding for a non-structural protein, VP9, utilizing RNA interference. Silencing of VP9 gene also effectively suppressed other gene region in the WSSV genome (wsv168 gene) as early as day 1 post infection (dpi). Three set-ups using Macrobrachium rosenbergii shrimp were prepared for treatment using VP9-dsRNA, GFP-dsRNA, and PBS. Each shrimp was challenge with WSSV, and survival rate was recorded. VP9- and GFP-dsRNA injected shrimps showed a significant survival rate of 80% and 70%, respectively, in contrast to 0% of the PBS injected shrimps at 25dpi. Re-infection of shrimp survivors using a higher viral titer concentration, concurrent with the infection of new shrimp samples for the PBS control group, resulted in a significant 67% survival rate for VP9-dsRNA compared to 0% with that of GFP-dsRNA and PBS group. Challenge test on two more species, Penaeus monodon and Marsupenaeus japonicus, also significantly increased survival after VP9-dsRNA treatment. Our results provided evidence that VP9 gene plays an essential role in WSSV replication and it can be a potent target gene in the development of RNAi therapeutics for shrimps.
authors.affiliation: The Graduate School, University of Santo Tomas, España, 1015 Manila, Philippines.
authors.forename: Rod Russel R
authors.initials: RR
authors.lastname: Alenton
authors.affiliation: Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Kondo
authors.affiliation: Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Hirono
authors.affiliation: The Graduate School, University of Santo Tomas, España, 1015 Manila, Philippines; Department of Biological Sciences, College of Science, University of Santo Tomas, España, 1015 Manila, Philippines; Molecular Biology and Biotechnology Laboratory, Research Cluster for Natural and Applied Sciences, University of Santo Tomas, España, 1015 Manila, Philippines. Electronic address: marybethmaningas@yahoo.com.
authors.forename: Mary Beth B
authors.initials: MB
authors.lastname: Maningas
mesh_terms: D000818:Animals; D015870:Gene Expression; D020868:Gene Silencing; D005814:Genes, Viral; D033541:Palaemonidae / Q000821:virology*; D046848:White spot syndrome virus 1 / Q000235:genetics*
keywords: Gene silencing; Macrobrachium rosenbergii; RNA interference; VP9; WSSV