Knockdown of heat shock protein 70 (Hsp70) by RNAi reduces the tolerance of Artemia franciscana nauplii to heat and bacterial infection

Abstract RNA interference (RNAi) was used to assess the role of the molecular chaperone Hsp70 in protecting nauplii of the crustacean, Artemia franciscana , against abiotic and biotic stressors. As revealed respectively by RT-PCR and immunoprobing of Western blots, the injection of A. franciscana females with Hsp70 dsRNA eliminated Hsp70 mRNA and protein in nauplii released from these animals. The loss of Hsp70 had no apparent effect on either embryo development or the viability of A. franciscana nauplii. The survival of nauplii lacking Hsp70, as compared to those containing the Hsp, was reduced 41% by heat stress and 34% upon Vibrio campbellii infection. A role for Hsp70 in protecting A. franciscana nauplii against heat stress and bacterial infection was demonstrated for the first time by using RNAi to knock down the protein. The results suggest that Hsp70 assisted in maintaining protein homeostasis within stressed cells while potentially stimulating the innate immune system of A. franciscana . Information of the type generated in this work has potential for application in the culture of A. franciscana and other commercially important aquatic invertebrates.