摘要

Athtabvirus, a bunya-like virus and chequa iflavirus infect redclaw crayfish (Cherax quadricarinatus) and they may cause mortality reaching 20-40% after about three weeks following transportation stress. Lesions were seen in the muscles of broodstock and juveniles and nerve cords of craylings. Using NextGen sequencing, the whole transcriptomes of a farmed case crayfish and a tank-reared, unaffected crayfish were assembled producing over 500,000 contigs. The average depth of reads was 18 replicates with a range from 15 to 44. The near complete sequences of the large and middle genome segments of a bunya-like virus were detected along with chequa iflavirus. The internal bunya-like motifs; RNA-dependent RNA polymerase on the L segment, and glycoprotein n (Gn) on the M segment were easily identified. In the opposite, positive-sense direction on the M segment, another presumed glycoprotein (glycoprotein c) with a low-density lipoprotein receptor (cysteine-rich) motif was identified by position specific iterated (psi)-BLASTp. The athtabvirus was related to Whenzhou Shrimp Virus 2 (E = 0.0, 43% amino acid identity), an unassigned, - ve sense ssRNA virus, and to peribunyaviruses (E = 10(-50-20)) In descending order of the number of RNA copies/0.2 mg of tissue, the organs most heavily infected were muscle (9.4 x 10(6)), nerve cord (5.24 x 10(6)), heart (4.07 x 10(6)), gills (3.96 x 10(6)), hepatopancreas (1.58 x 10(6)) and antennal gland (6.6 x 10(5)). Given the tissue tropism (muscle and nerves) of athtabvirus and the original lesions, this virus is implicated in being involved in the mortalities in crayfish after transportation.

  • 出版日期2018-5-2