A study of viral coat protein accumulation in lily chloroplasts from mixed virus infections of Lily mottle virus and Cucumber mosaic virus

Abstract

Two viruses that frequently occur in many Lilium species are Lily mottle virus (LMoV) and Cucumber mosaic virus (CMV), which usually co‐infect lilies causing severe disease symptoms. Recent reports have revealed that the viral coat protein (CP) affects chloroplast ultrastructure and symptom development. This study used western blot analysis to confirm that in leaves infected by mixed virus infections of LMoV and CMV, CPs of both viruses were accumulated in lily chloroplasts. Immunogold labelling further demonstrated that both the LMoV CP and CMV CP were localized in the stroma and the thylakoid membranes of the chloroplasts. In addition, it was found that CPs of both viruses were rapidly transported into isolated, intact chloroplasts (in vitro), and their transport efficiencies were positively related to CP concentrations. The lowest transmembrane concentration of CMV CP decreased from 38 μg mL−1 recorded in the single CMV CP import system to 10 μg mL−1 in the mixed import system of LMoV CP and CMV CP. CPs of both viruses exhibited species selection in their transmembrane transport into chloroplasts. This is the first report that the CPs from two viruses (LMoV and CMV) are simultaneously present in lily chloroplasts. Accumulation of high levels of LMoV CP and CMV CP inside the chloroplast appears to contribute to a synergistic interaction inducing the development of mosaic symptoms.

Dynamic Transcriptional Profiles ofArabidopsis thalianaInfected byTomato spotted wilt virus

“…Immunogold labeling has revealed Lily mottled virus coat protein localized to chloroplasts. The overaccumulation of this protein inhibits PSII activity, causing mottling symptoms (Zhang et al 2019). The studies described above showed correlations between photosystem damage and chlorotic symptoms; our results support these findings.…”

Advancements in Lily Viruses Management: Challenges and Solutions in Elimination and Detection

“…LSV and its co-infections with CMV or LMoV have been reported in various endemic regions worldwide. Some of the regions where these viruses have been identified include: the Netherlands, China, Japan, and the United States [21,27,98]. Mixed infection with these viruses leads to severe symptoms like smaller flowers, lower bulb yield, and growth reduction.…”

“…Consequently, the ID-ELISA method and IC-RT-PCR assays have been developed for efficient lily virus detection [104]. These methods were recommended for further control, surveys, and also to prevent lily infection by most of the viruses that occur in Lanzhou/Gansu Province and NingXia, the most important lily production areas in China [21,98]. Next-generation sequencing: This is a high-throughput sequencing technique that can detect and identify viral sequences in a sample.…”