NEW PLANT VIRUS AND VIROID RECORDS IN NEW ZEALAND: UPDATE 2008-2010

C. Delmiglio, L.I. Ward, B.S.M. Lebas, J. Tang, L.W. Liefting, B.D. Quinn, S. Veerakone, Z. Perez-Egusquiza and G.R.G. Clover

Overview

• MAF’s Plant Health and Environment Lab• Diagnostic techniques• New Virus records• New Viroid records• Brief discussion

Plant Health & Environment Laboratory’s role & activitiesPHEL is responsible for the identification and diagnosis of suspected exotic pests and diseases affecting plants, plant products and the environment.

Diagnosis of plant pests and diseases• Intercepted at border or in quarantine• Pre-determined testing of post-entry quarantine (PEQ) plants• Post-border interceptions & surveillance

– Passive surveillance– Active surveillance

• Investigation & responses• Confirmation of new records (i.e. from other institutions)

Diagnostic Techniques used by the Virology TeamThe Virology Team receives about 300 samples a year. Diagnosis made by:

• Inoculation to indicators (woody & herbaceous)

• Particle morphology (electron microscopy)

• Serology (e.g. ELISA, TPIA)• Molecular (e.g. conventional/ real-time

PCR, hybridisation, sequencing)• rPAGE & dsRNA profiling

New virus records 2008-2010

12 viruses

Symptoms in virus-infected plants ranged from latent infections (i.e. FLV inFuchsia x hybrida) to chlorosis or necrosis and severe leaf deformation.

Virus symptoms

IYSV-infected onion showing diamond-shaped lesions on flower stalks.

Ipomoea setosainfected with SPVG and SPV2, showing mottling and vein clearing.

Leaves of the TRSV-infected Sophora microphylla (kowhāi tree) showing small chlorotic lesions.

Symptoms in virus-infected plants ranged from latent infections (i.e. FLV inFuchsia x hybrida) to chlorosis or necrosis and leaf deformation.

Virus symptoms

Mosaic and leaf distortion in Persicaria odorata (Vietnamese mint) infected with two uncharacterised carmoviruses

HeNNV-infected Helleborus sp. (winter rose),showing severe leaf distortion and necroticlesions on leaf margins and flowers.

New viroid records 2008-2010

4 new records

Symptoms in viroid-infected plants ranged from no apparent symptoms(i.e. CVd-III in the citrus cultivars tested and HSVd in hop and grapevine) toleaf speckling for GYSVd-1 in grapevine, or chlorosis and severe leafdeformation.

Viroid symptoms

PSTVd in cape gooseberry

PSTVd from cape gooseberry confirmed as pathogenic strain in tomato (cv money maker)

Conclusive discussion• The economic impact of the 12 viruses and 4 viroids recorded for New Zealand is currently unknown.

• Of the Allium viruses identified, IYSV has recently emerged as a serious disease with reported total crop losses in Brazil and parts of the USA. However, such losses have not yet been observed in NZ.

• The viruses of sweet potato identified are of potential economic significance, especially as the majority of plants are infected with a mixture of viruses & synergistic effect have been documented overseas.

• Although PSTVd has been reported in cape gooseberry, it has never been found in potato crops and is still regulated, and is under official control in glasshouse tomato and capsicum crops.

Thanks to all in the ‘Virology & PEQ’ Team: Lia Liefting, Lisa ward, Bénédicte Lebas, Joe Tang, Brian Quinn, Stella Veerakone and Zoila Perez.Thanks also to the growers and the general public who kindly allowed us to sample their crops or submitted samples for testing

Acknowledgements