New hosts of “Candidatus Phytoplasma australiense” in New Zealand

Abstract

“Candidatus Phytoplasma australiense” occurs in New Zealand and Australia where it is associated with plant diseases in native, weed and crop plants. In New Zealand, this phytoplasma is historically associated with the diseases, Phormium yellow leaf, Strawberry lethal yellows, Cordyline sudden decline and Coprosma lethal decline. Between January 2009 and July 2010, four new hosts of “Ca. P. australiense” have been identified in New Zealand: potato (Solanum tuberosum), Jerusalem cherry (Solanum pseudocapsicum), swan plant (Gomphocarpus fruticosa) and celery (Apium graveolens), as well as a new disease association in boysenberry (Rubus hybrid). A 1.2 kb region of the 16S rRNA gene of the phytoplasma amplified from the new hosts was identical to each other. Partial tuf gene sequence analysis of 32 isolates from potato, Jerusalem cherry, swan plant, celery, boysenberry as well as from the Zeoliarus planthopper vector, revealed that they belonged to two separate subgroups, tuf variant VII and tuf variant IX. Two of the isolates, one from potato and the other from celery, contained a mixed infection of both phytoplasma subgroups.