4th meeting of the EPPO Panel on Diagnostics in Virology 
and Phytoplasmology

 

Paris (FR), 2016-04-05/07

 

 

The 4th meeting of the EPPO Panel on Diagnostics in Virology and Phytoplasmology took place in the EPPO headquarters. The Panel continued its work on the preparation and revision of diagnostic protocols for viruses and phytoplamas.

 

Discussions on horizontal Standards for viruses and phytoplasmas

  • Generic Standard on the detection of pospiviroidsViruses
    General discussions on the content of the Standard took place. It was agreed that it would be ideal to have in a single Standard the generic detection and the identification of specific pospiviroids. It was agreed that work on this Standard should continue via email and a teleconference will be organised in August 2016 to further work on the protocol.
     
  • Generic Standard on the detection of phytoplasmas
    The need to develop an EPPO Standard on the generic detection of phytoplasmas was discussed. The Panel considered that the recently adopted IPPC Standard on Phytoplasmas provided appropriate guidance but may need to be converted in the EPPO format.
     
  • Standard on DNA barcoding as an identification tool for regulated plant pests
    The horizontal Standard on DNA barcoding as an identification tool for regulated plant pests was sent for country consultation on March 11 2016. The report of the test performance study organized in the framework of a Euphresco project is available through the EPPO Database on Diagnostic Expertise. 
     
  • ISO/CD 13484 Foodstuffs - Molecular Biomarker Analysis - General requirements for molecular biology analysis for detection and identification of plant pests
    The Panel was informed of the progress made in ISO with this Standard which covers indirect tests performed in plant pest diagnostic laboratories.  The International Plant Protection Convention (IPPC) Secretariat, EPPO experts, members of the Panel on Diagnostics and Quality Assurance and more recently the EPPO Secretariat are represented in the group preparing the document as representatives of the plant health field. It was noted that the EPPO Secretariat would inform the Panel of any content in the document deserving special attention.
     
  • Guidelines for the Authorization of Laboratories
    The Panel was informed that the Standard had been sent for country consultation and may be adopted in 2016.
     
  • Guidelines on National Reference Laboratories
    The 3rd Workshop for Heads of Laboratories suggested that, given the current developments in this area, the work on these guidelines could be postponed to 2018.

 

Discussions on pest-specific diagnostic protocols

The Panel discussed the following diagnostic protocols:

Viruses

  • New protocol: Andean potato latent virus and Andean potato mild mosaic virus
    Testing for these viruses is mainly done in the context of post entry quarantine. The Panel discussed which molecular tests should be included in the protocol and which of these should be recommended for detection or identification. The Panel agreed that this protocol should be sent for country consultation.
  • Revision of PM 7/002 Tobacco ringspot virus 
    This Diagnostic protocol was developed in 2000 and was revised to add more recently developed tests. The Panel reviewed the molecular tests proposed for inclusion in the protocol. It was noted that a generic PCR test on nepoviruses is currently under development in ANSES, but more work is needed to validate it. It was noted that validation data is only available for the DAS-ELISA test which was the test the Panel members use most often.
  • PM 7/049 Tomato ringspot virus
    A teleconference will be organised at the end of 2016 to finalize the work on the Standard so it can be sent for country consultation and then allow time for the Panel to be able to review the comments received from NPPOs at the next Panel meeting.
  • PM 7/033 Potato spindle tuber viroid, PM 7/032 on Plum pox virus
    It was noted that the EPPO Standards should be aligned to the respective IPPC protocol.                                           
  • PM 7/030 Beet necrotic yellow vein virus
    The results of a study to evaluate the performance criteria of tests used for the detection of Beet necrotic yellow vein virus was presented. Further work is needed on this protocol and will continue at the next Panel meeting.
  • PM 7/034 Generic detection and species-specific detection of Tomato spotted wilt virus, Impatiens necrotic spot virus, Watermelon silver mottle virus and Chrysanthemum stem necrosis virus
    The Panel noted the publication of a generic detection test by Dutch colleagues. The protocol should be revised to incorporate this test and will be presented at the next Panel meeting.
  • PM 7/081(1) Cucumber vein yellowing virus
    The Panel noted that there was no urgency for a revised Standard for this pest.
     
  • Other standards on viruses and viroids pending revision
    -     PM 7/006 Chrysanthemum stunt viroid: The work on the Standard is on hold, pending the finalization of the generic Standard on the detection of Pospiviroids.
    - PM 7/050 Tomato yellow leaf curl virus and Tomato mottle virus: An IPPC Standard is in progress on Begomovirusestransmitted by Bemisia tabaci. Revision should follow the adoption of the IPPC protocol.
    - PM 7/31 (1) Citrus tristeza virus: An IPPC protocol on Citrus tristeza virus was sent for Member Consultation in 2015. As soon as the IPPC protocol is finalised the EPPO Standard will be revised to align its content.

 

Phytoplasmas

  • PM 7/62 & PM 7/63 ‘Candidatus Phytoplasma mali’, ‘Ca. P. pyri’, ‘Ca. P. prunorum’
    The Panel agreed that this revised protocol should be sent for country consultation.
  • PM 7/061 ‘Candidatus phytoplasma aurantifoliae’
    A revision of the Diagnostic protocol on ‘Candidatus phytoplasma aurantifoliae’ will be considered in the next months.

 

Future priorities for revision and future programme for specific protocols
Panel members identified the following species as the highest priorities for the possible development of new diagnostic protocols: Tomato Leaf Curl New Delhi virus and Grapevine Pinot gris virus.

 

General discussions

  • Positive controls and cross-contamination
    Panel members considered that using cloned products as positive amplification controls (PAC) presents a risk of contamination but recognized that this is now becoming more frequent for standardization purposes. The Panel recommended that a warning should be added when this recommendation is made. A modification of the standard text in the EPPO Instruction to authors will be proposed to the Panel on Diagnostics and Quality Assurance.
     
  • Storage conditions of DNA/RNA
    The Panel suggested that storage conditions for DNA/RNA should be harmonized between protocols and that this should be discussed in the different specialized Panels. It was noted that depending on the methods and the chemicals used, storage conditions may need to differ.
     
  • Flexible scope
    The Panel noted that the National Reference Center, NL is currently discussing with the Dutch accreditation body a type of flexible scope accreditation called ‘Phytoflex’. Feedback on this accreditation process would be valuable to continue the discussion engaged with the European Association for Accreditation (EA) on the implementation of flexible scope in plant health.

 

Update on new activities within EPPO

The plans for the Euphresco Strategic Research Agenda were presented and Panel members provided suggestions on medium term objectives for research and infrastructure needs in the phytosanitary area. The information collected at the various EPPO Panels and workshops will be presented to Euphresco members and activities will be identified to produce a consensus document.

The Panel considered two Q-collect documents (deliverables) on quality assurance for reference collections and on the terms of reference and criteria for a sustainable network of reference collections. The Panel agreed with the Panels on Diagnostics and Quality Assurance and on Diagnostics in Mycology that developing quality guidelines for reference biological material was preferable to quality guidelines for an entire collection.

The results of the survey organized among laboratories involved in official diagnostics on the use of the Q-bank database were presented; the objective of the survey was to evaluate the potential benefits of a project to bring Q-bank into the framework of EPPO.   Respondents suggested that the focus for integration of Q-bank into the EPPO system should be on: DNA sequences for blasting, protocols for barcoding, information on where to find biological material. Other types of information currently present in Q-bank such as geographical distribution, host plants, keys, pictures etc. are available (or can be integrated in a longer term) in existing EPPO datasets (e.g. the EPPO Global Database, EPPO Diagnostic protocols).
A project for integration of Q-bank data was presented to the EPPO Executive Committee in April 2016 and discussions will continue in September at the EPPO Council.

The next meeting will be held in Germany in November 2017.