Variability of kinetoplast DNA from plant trypanosomatids responsible for Hartrot and Marchitez diseases

The kinetoplast DNA of 27 plant trypanosomatid stocks (22 intraphloemic Phytomonas associated with coconut Hartrot, oil palm Marchitez, or decay of Alpinia purpurata, 3 Phytomonas isolates from latex, and 2 fruit 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 isolates from latex. Restriction endonuclease analysis showed that for almost all of the isolates minicircles were heterogeneous in base sequence. Cross-hybridization experiments were performed by Southern blot. A high sequence similarity only occurred between isolates of the same class of minicircle sizes, except for the 1.6-kb class, in which isolates from fruits and isolates originating from diseased coconut belonged to two hybridization groups. Moreover, the intraphloemic isolates that belonged to two classes, 1.6 and 1.8 kb, showed sequence similarity. These data confirm the existence of at least two groups of intraphloemic trypanosomatids associated with wilts, several groups of latex trypanosomatids, and one group of fruit trypanosomatids and could help in the classification of the "lower" trypanosomatids