NIR-assisted orchid virus therapy using urchin bimetallic nanomaterials in phalaenopsis

Abstract

The use of nanoparticles has drawn special attention, particularly in the treatment of plant diseases. Cymbidium mosaic virus (CymMV) and Odontoglossum ring spot virus (ORSV) are the most prevalent and serious diseases that affect the development of the orchid industry. In this study we treated nanoparticles as a strategy for enhancing the resistance of orchids against CymMV and ORSV. After chitosan-modified gold nanoparticles (Au NPs) were injected into Phalaenopsis leaves, the injected leaves were exposed to 980 nm laser for light–heat conversion. To evaluate virus elimination in the treated Phalaenopsis leaves, the transcripts of coat protein genes and the production of viral proteins were assessed by reverse transcription-Polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The expression of coat protein genes for both CymMV and ORSV was significantly lower in the chitosan-modified Au NP-treated Phalaenopsis leaves than in the control. Similarly, the amount of coat proteins for both viruses in the Phalaenopsis leaves was lower than that in the control (without nanoparticle injection). We propose that the temperature increase in the chitosan-modified Au NP-treated Phalaenopsis tissues after laser exposure reduces the viral population, consequently conferring resistance against CymMV and ORSV. Our findings suggest that the application of chitosan-modified Au NPs is a promising new strategy for orchid virus therapy.