Biological Characterisation of a Divergent Dragon Fruit ( Hylocereus spp.) Strain of Cactus Carlavirus‐2 ( CCV ‐2_Pit)

Abstract

A dragon fruit strain of cactus carlavirus‐2 (CCV‐2_Pit) was biologically characterised through the development of an infectious clone, enabling the evaluation of single‐virus infections independently of other viruses. The complete genome (8454 nt) shares 77% nucleotide identity with the previously described CCV‐2 isolate, supporting their classification as highly divergent strains of the same species. Agroinoculation of the infectious clone resulted in systemic infection of three commercial Hylocereus species at a low infection rate (20%), with infected plants remaining asymptomatic under greenhouse conditions. CCV‐2_Pit was not mechanically transmitted to dragon fruit or any of the herbaceous hosts tested, whereas graft inoculation resulted in 60%–100% transmission among commercial Hylocereus species. The infectious clone developed in this study provides a valuable tool for future investigations of CCV‐2 biology, virus–host interactions and the aetiology of viral diseases in dragon fruit.