Abstract

Heteroduplex mobility assay (HMA) was used to determine if genetic variability existed amongst isolates of Australian grapevine yellows (AGY) and the Buckland Valley grapevine yellows (BVGY) phytoplasmas. Genetic variability was detected in two isolates of AGY phytoplasma from the same grapevine when they were compared with an AGY phytoplasma standard using HMA of the elongation factor Tu (tuf) gene. HMA of the tuf gene also showed that an isolate of papaya dieback (PDB) phytoplasma, which is closely related to AGY phytoplasma, was different from the AGY phytoplasma standard. The two AGY variant phytoplasmas and PDB phytoplasma were indistinguishable from each other when they were compared using HMA of the tuf gene. No variability was observed amongst isolates of BVGY phytoplasma using HMA of the tuf gene.