Specificity of phytopathogenic trypanosomes (Phytomonas spp.)

#Phytomonas# spp. do exist in plants. Different species of plants host #Phytomonas#, but significant pathogenicity has been observed in only four plants : coconut (Hartrot disease), oil palm (Marchitez disease), coffee (Phloem necrosis) and #Alpinia purpurata# (wilt). It is possible to differentiate #Phytomonas# specifically associated with this diseases from the others by several criteria. At the biological level : 1°) They are located in the sieve tubes, whereas others occur in latex tubes or in the fruits, 2°) Primoculture of pathogenic #Phytomonas# (Phloem restricted) can be obtained only with insect cell cultures. At the molecular level : 1°) Phloem restricted #Phytomonas# can be set apart by their schyzodeme, 2°) They harbor a double stranded RNA which could be of viral origin. Moreover, isolates of phloem restricted #Phytomonas# can be characterized by the size of the minicircles of kinetoplastic DNA, and their restriction endonucleases pattern. (Résumé d'auteur