Please check the following link.

https://www.researchgate.net/publication/269288512_Cryopreservation_for_eradication_of_Jujube_witches'_broom_phytoplasma_from_Chinese_jujube_Ziziphus_jujuba

Article Cryopreservation for eradication of Jujube witches' broom ph...

Please check the PDF attachments also.

Please have a look at this link also.

https://www.researchgate.net/publication/290571646_Propagation_and_long-term_preservation_of_several_isolates_of_jujube_witches'_broom_and_Paulownia_witches'_broom-phytoplasmas_in_in_vitro_cultured_plantlets_and_grafting_transmission_of_the_pathogens_

Article Propagation and long-term preservation of several isolates o...

Wongwarat has proposed some methods which will be of significance to you.

Article Effective methods of preserving SCWL-diseased sugarcane leav...

Although phytoplasma are important for fruit trees, I have very little expertise.

You can find some answers by reading the attached files.

All the Best!

Thanks to all of you Arvind Singh, Rashid C.A Kawawa and F.C. Marin for your answers. I will go through the publications suggested by you.

Thanks Amal... Actually I want to know whether it is possible to store the phytoplasma in a culture form?

Thank you Amal.

Maneesha, some groups have reported that some types of phytoplasma can be cultured. Here´s the link to some of that research:

hope it helps.

http://www.sciencedirect.com/science/article/pii/S0167701216301282?via%3Dihub