One type of VEGFR is involved in WSSV infection to the Pacific whiteleg shrimp Litopenaeus vannamei

• The VEGFR gene was identified and characterized in Litopenaeus vannamei.
• The expression of LvVEGFR was up-regulated after WSSV infection.
• Silencing of LvVEGFR increased the survival rate of shrimp during WSSV infection.

VEGF signaling pathway plays vital roles in many physiological processes including cell proliferation, differentiation, migration, survival, cell–cell communication, vessel permeability and virus-host interaction in mammalian species. However, the VEGF signaling pathway and its biological function are still poorly understood in crustaceans. In the present study, an essential member of VEGF signaling pathway, VEGF receptor (LvVEGFR), was isolated from Penaeid shrimp Litopenaeus vannamei and its function during virus infection was analyzed. The deduced amino acid sequence of LvVEGFR possessed all common features of VEGFRs reported in other species, including a signal peptide, six IG-like domains, one immunoglobulin subtype 2 domain, a transmembrane domain, a juxtamembrane domain, a protein kinase domain separated by a kinase insert sequence, one ATP binding site and one tyrosine-protein kinase active site. LvVEGFR is mainly expressed in hemocytes and intestine. The transcriptional level of LvVEGFR could be obviously up-regulated in hemocytes and intestine after WSSV infection. Silencing of LvVEGFR gene by double-strand RNA (dsRNA) interference could not only lead to a decrease of virus copy number in WSSV infected shrimp, but also reduce the mortality of shrimp during WSSV infection. These data suggested that VEGF signaling pathway might play an important role during viral infection to shrimp.