Ash trees (Fraxinus spp.) are widely distributed through European, Asian, and North American temperate zones. There are numerous recently identified pests and pathogens that have killed hundreds of millions of ash worldwide. In 2014, white ash trees in Colorado exhibited symptoms of chlorotic patches that increased in size through the growing season and developed necrotic lesions. Partially purified extracts of symptomatic leaves examined by transmission electron microscopy identified spherical virus-like particles. Next generation RNA sequencing of symptomatic tissue identified five virus-like contigs with similarity to both partitiviruses and caulimoviruses. Primers designed from the putative contigs amplified products of the expected size from both inoculated plants and wild ash seedlings. Further work is required to complete the virus genomes, phylogenetic analysis, complete Koch’s postulates, and determine the distribution of these viruses in the Fraxinus genus.
- Cryptic virus
- Plant pararetrovirus