Résumé
The genetic polymorphism of 30 isolates of plant trypanosomatids
colloquially referred to as plant trypanosomes was
assayed by means of RAPD. The principle objectives of this study were to
assess the discriminative power of RAPD
analysis for studying plant trypanosomes and to determine whether the
results obtained were comparable with those from
a previous isoenzyme (MLEE) study. The principle groups of plant trypanosomes
identified previously by isoenzyme
analysis – intraphloemic trypanosomes, intralaticiferous trypanosomes
and trypanosomes isolated from fruits – were also
clearly separated by the RAPD technique. Moreover, the results showed a
fair
parity between MLEE and RAPD data
(coefficient of correlation = 0·84) and the two techniques
have comparable discriminative ability. Most of the separation
revealed by the two techniques between the clusters was associated with
major biological properties. However, the RAPD
technique gave a more coherent separation than MLEE because the
intraphloemic isolates, which were biologically similar
in terms of their specific localization in the sieve tubes of the plant,
were found to be in closer groups by the RAPD. For
both techniques, the existence of the main clusters was correlated with
the
existence of synapomorphic characters, which
could be used as powerful tools in taxonomy and epidemiology.