Houda,

one of main problems of latent/early virus infection diagnostics is that virus was not present in the taken sample, but plant has been infected. For instance, vine grape plant must be tested several times during 12 moths to be accepted as virus-free.  Other aspects must be specifically described (crop, virus, plant stage, temperature) before the answer.

Dear  Alex Ignatov

Thanks for your answer,

Best regards

Houda

Absolutely true that Molecular Biology tools are helping us detect the plant viruses. ELISA, PCR based detection so on. Sometimes plant may be symptomless but PCR based detection or ELISA results confirm the occurence of virus in the test sample. Some drawbacks may be there but overall, molecular biology tools are doing a good service for virologists for detection or diagnosis of plant viruses in test samples

Definitely.

1. ELISA method is the routinely used one used for plant virus. However its being replaced by PCR since sensitivity of PCR is more.

1. Virus indexing is a process used to diagnose presence of virus in infected plants especially tissue cultured plants.

1. Some viruses do local infections, are present locally in some particular tissues and long distance movement is absent within the plant.If we unfortunately take other plant part for ELISA or PCR our results turn out to be negative.

2. Storing samples in -80 for more than 4-5 months may cause structural deterioration of virus coat protein leading to unexpected serological test results. I faced a similar type of problem.

For some/many plant viruses, the plant immune system is temperature dependent.  In warm climates, during the heat of summer, the virus is mainly in the roots.  However, in the cool of spring or late fall the virus can be observed / detected in the above ground parts of the plant.

The following link will take you to a description of what happens with PNRSV and roses:

https://sites.google.com/site/temperatureandrosemosaicvirus/

Dear Henry Anton Kuska 

Thanks for your answer

During few days I'll Add a research about rose viruses in Syria. ,also I published  one on Apple mosaic virus and face  same problem of latent infection, and also in the hot summer for alfalfa mosaic virus on medicago sativa most symptoms disappears.

It is really not a question so much as that of molecular biology will not find solutions to all the problems of viral plant diseases and my new lectures concentrate on the role of aptamers

Best regards

Houda

Molecular biology can be applied in any field, human virus detection or plant virus detection.  These are best methods though not economic for large scale indexing.  These are good for detection of viruses in starting material such as cuttings of apple, , or seeds , or vegetative propagation of plants such as banana or where plants are raised by tissue culture.

There is no doubt about this amd number of transgenics are available for various biotic and abiotic stresses. You must have a good knowledge and skills. Best

Hi Houda,

As several of our colleagues said, you can detect the virus by ELISA or PCR, but you have to know at least which virus could be infecting your plant, because both test are very specific to the epitope (usually ELISA test to detect virus use antibodies against some protein in the virus capsid); or DNA sequence in PCR. In my opinion you can use any of those methods even in large scale like 100 samples. Those tests are use to certified free-virus crops.

I was looking for some generic protocol that you can use and I attached it here:  

http://scigine.com/method.php?ID=5622

Nothing to add,some collegaues nave already hinted  about what you needs

pleease refer the pollenBiology manuual by KRShivanna of Dekhi University  all protocolsm  are givenISearch Googke Porvide me tour mail if I will commect you throiugh is mail id, He is the best in mu opinion to help you He reitired from DelhiUniversity and noe in  Banagalote

Dear All

When a rapid analysis of a reduced number of samples is performed and the protocols have been suitably optimised and also when the presence of false positives is not crucial because the main goal is the quality of the negatives. However, for quarantine pathogens or in critical cases of export-import, experience advises the use of more than one technique, based on different biological principles, to avoid the risk of false positives and false negatives. Besides, the use of real-time PCR for routine analysis could still be too expensive for most laboratories.

Best Regards

Houda

Dear All

When a rapid analysis of a reduced number of samples is performed and the protocols have been suitably optimised and also when the presence of false positives is not crucial because the main goal is the quality of the negatives. However, for quarantine pathogens or in critical cases of export-import, experience advises the use of more than one technique, based on different biological principles, to avoid the risk of false positives and false negatives. Besides, the use of real-time PCR for routine analysis could still be too expensive for most laboratories.

Best Regards

Houda