ABSTRACT
Rust fungi are the largest group of obligate plant pathogens and cause severe damage to global forests and agricultural security. Meliosma myriantha, a tree species native to East Asia (China, Japan, and Korea), is vulnerable to three rust species: Neophysopella meliosmae, N. meliosmae-myrianthae, and N. vitis. The early symptoms of infection are indistinguishable between these species, making an accurate and rapid diagnosis challenging. The urediniospores of N. meliosmae-myrianthae and N. vitis are also known to infect economically relevant grapevines (Vitis spp.) and ivies (Parthenocissus spp.), respectively, rendering early detection and identification even more important. To address this issue, we developed a multiplex quantitative polymerase chain reaction assay equipped with TaqMan probes targeting the internal transcribed spacer rDNA sequences specific to the three rust pathogens. This assay successfully detected minute quantities (5 fg for N. meliosmae-myrianthae and 50 fg for N. meliosmae and N. vitis) of DNA from the three Neophysopella species and demonstrated consistent reliability when applied to fresh and herbarium samples collected from M. myriantha, grapevines, and ivies. In conclusion, this novel assay is a rapid and robust diagnostic tool for the three rust pathogens, N. meliosmae, N. meliosmae-myrianthae, and N. vitis, and offers the potential to identify and detect their global movement and spread to grapevines, ivies, and trees.
Subject(s)
Basidiomycota , DNA, Fungal , Multiplex Polymerase Chain Reaction , Plant Diseases , Basidiomycota/genetics , Basidiomycota/isolation & purification , Basidiomycota/classification , Plant Diseases/microbiology , DNA, Fungal/genetics , Multiplex Polymerase Chain Reaction/methods , DNA, Ribosomal Spacer/genetics , Real-Time Polymerase Chain Reaction/methods , Reproducibility of Results , Vitis/microbiologyABSTRACT
Virginia creeper (or five-leaved ivy; Parthenocissus quinquefolia) is one of the most popular and widely grown climbers worldwide. In September 2021, Virginia creeper leaves with typical rust symptom were found in an arboretum in Korea, with severe damage. Globally, there is no record of a rust disease on Virginia creeper. Using morphological investigation and molecular phylogenetic inferences, the rust agent was identified as Neophysopella vitis, which is a rust pathogen of other Parthenocissus spp. including Boston ivy (P. tricuspidata). Given that the two ivy plants, Virginia creeper and Boston ivy, have common habitats, especially on buildings and walls, throughout Korea, and that N. vitis is a ubiquitous rust species affecting Boston ivy in Korea, it is speculated that the host range of N. vitis may recently have expanded from Boston ivy to Virginia creeper. The present study reports a globally new rust disease on Virginia creeper, which could be a major threat to the ornamental creeper.
