VARIABILITY OF KINETOPLAST DNA FROM PLANT TRYPANOSOMATIDS RESPONSIBLEFOR HARTROT AND MARCHITEZ DISEASES

The kinetoplast DNA of 27 plant trypanosomatid stocks (22 intraphloemi c Phytomonas associated with coconut Hartrot, oil palm Marchitez, or d ecay of Alpinia purpurata, 3 Phytomonas isolates from latex, and 2 fru it trypanosomatids) was studied. Four classes of minicircle sizes were obtained: 1.6 and 1.8 kb for isolates originating from coconut palms, oil palms, Alpinia purpurata, and fruits; 850 bp and 2.8 kb for isola tes from latex. Restriction endonuclease analysis showed that for almo st all of the isolates minicircles were heterogeneous in base sequence . Cross-hybridization experiments were performed by Southern blot. A h igh sequence similarity only occurred between isolates of the same cla ss of minicircle sizes, except for the 1.6-kb class, in which isolates from fruits and isolates originating from diseased coconut belonged t o two hybridization groups. Moreover, the intraphloemic isolates that belonged to two classes, 1.6 and 1.8 kb, showed sequence similarity. T hese data confirm the existence of at least two groups of intraphloemi c trypanosomatids associated with wilts, several groups of latex trypa nosomatids, and one group of fruit trypanosomatids and could help in t he classification of the ''lower'' trypanosomatids.