Metagenomics of a historical Ophiovirus citri isolate in Australia and its findings for RT-qPCR detection

Ophiovirus citri is a graft-transmissible citrus virus and is the presumed causal agent of citrus psorosis disease. Australian historical isolate CL222 induces symptoms typically associated with psorosis of oakleaf patterns and leaf flecking on inoculated Symons sweet orange biological indicator plants. Genomic analysis of CL222 revealed a nucleotide match of 99.8-99.9% to Chinese CPsV genomes. The detection of a single nucleotide variation in the coat protein gene of the Australian isolate CL222 enabled the design of an improved RT-qPCR probe to enhance virus detection. O. citri is rarely detected in field trees in Australia, likely due to the widespread use of pathogen-free propagation material.