Symposia and Oral Abstracts

Viral pathogens pose a serious threat to the cultured shrimp industry. Hepatopancreatic parvo-like virus (HPV) is a shrimp parvovirus that has been reported to be widely distributed in a variety of wild and cultured penaeid shrimp species throughout the world. The occurrence of HPV infection was examined in a population of commercially produced banana shrimp (F. merguiensis ) in North Queensland, Australia. Large differences (up to 3 orders of magnitude) were observed in HPV copy numbers between families bred and grown together. Heritability for HPV copy number was estimated to be moderate to large (0.40 ± 0.13). To further investigate the genetic mechanisms of resistance to HPV, hepatopancreas tissue sampled from 4 animals from 6 families, 3 exhibiting high viral load and 3 exhibiting lower viral load (n=24), was subjected to RNA-Seq, de-novo transcriptome assembly and subsequent gene expression analysis. These data revealed over 400 transcripts that were differentially expressed between the high and low families and uncovered a rich set of genes involved in immune system related functions. Over 80 of these transcript sequences exhibited homology with genes associated with invertebrate innate immune responses to known bacterial and viral pathogens. Comparative analysis of gene sequences among family groups revealed a number of interesting single nucleotide variations. This research has provided some insight into our understanding of the mechanisms involved in the resilience of this shrimp species to a naturally occurring viral pathogen