First Report of Cherry leaf roll virus in Hydrangea macrophylla

Area of Science:

• Plant Pathology
• Virology
• Horticultural Science

Background:

• Hydrangea (Hydrangea spp.) is a globally cultivated ornamental shrub with 13 known viruses.
• Virus-like symptoms, including leaf deformation and chlorosis, were observed on imported Hydrangea macrophylla 'Sumiko' plants.

Purpose of the Study:

• To identify the causal agent of disease symptoms in hydrangea plants.
• To confirm the presence and characterize the virus affecting the ornamental shrub.

Main Methods:

• Mechanical inoculation of symptomatic hydrangea sap to indicator plants (Nicotiana occidentalis, N. tobacum, Chenopodium quinoa).
• Transmission electron microscopy to visualize viral particles.
• Reverse transcription-polymerase chain reaction (RT-PCR) and sequencing for viral identification.
• Double antibody sandwich-ELISA for serological confirmation.

Main Results:

• Systemic symptoms, including necrosis and leaf deformation, developed in indicator plants.
• Isometric viral particles approximately 28 nm in diameter were observed.
• RT-PCR yielded an amplicon of ~1,150 bp, confirming the presence of Cherry leaf roll virus (CLRV).
• Sequence analysis showed high nucleotide identity (99-98%) to known CLRV isolates.
• ELISA and immunocapture RT-PCR further confirmed CLRV presence.

Conclusions:

• This is the first report of Cherry leaf roll virus (CLRV) infecting hydrangea.
• CLRV, a nepovirus, can spread via infected propagation material, posing a risk to commercial nurseries.
• The economic impact of CLRV on hydrangea flower quality remains to be investigated.