Phytoplasma cultivation

The possibility to grow phytoplasmas in complex media as the mycoplasmas was ruled out for more than 40 years due to the inconsistency of the first isolation trials. The use of micropropagated infected periwinkle shoots first and tissues infected directly from the fields on artificial media was recently confirmed. Isolation and cultivation together with the first biochemical and biological characterization of some phytoplasmas were consistently obtained. Phytoplasmas were successfully grown from grapevine, cassava and coconut palm tissues severely infected and in some cases also from asymptomatic tissues from trees or plants growing in severely infected areas. Phytoplasmas from diverse ribosomal groups were isolated in particular from cassava with frog skin the detected prokaryotes in culture were molecularly identified as belonging to the 16SrIII group as in the original plants. Aster yellows and ‘stolbur’ phytoplasmas, group 16SrI and 16SrXII, respectively, were consistently grown from diverse host plants such as grapevine and coconut palms. Seed transmission in corn of aster yellows phytoplasmas was also confirmed by isolation from seedlings of viable cells. The growth and biochemical and biological characterization of these bacteria is therefore the most important recent step in the study of phytoplasmas that will allow to improve their knowledge and to carry out focused management in the field in order to reduce their impact on cultivated and wild crops worldwide.