Association of 'Candidatus Phytoplasma australiense' with green petal and lethal yellows diseases in strawberry

The identity of phytoplasmas detected in strawberry plants with green petal (SGP) and lethal yellows (SLY) diseases was determined by RFLP analysis of the 16S rRNA gene and adjacent spacer region (SR). RFLP and sequence compa risons indicated that the phytoplasmas associated with SGP and SLY were ind istinguishable and were most closely related to 'Candidatus Phytoplasma aus traliense', the phytoplasma associated with Australian grapevine yellows, p apaya dieback and Phormium yellow leaf diseases. This taxon lies within the aster yellows strain cluster. Primers based on the phytoplasma tuf gene, w hich amplify only members of the AY strain cluster, amplified a DNA product from the SGP and SLY phytoplasmas. Primers deduced from the 16S rRNA/SR of P. australiense that amplify only members of this taxon amplified rDNA seq uences from the SGP and SLY phytoplasmas. Primers that selectively amplify members of the faba bean phyllody (FBP) phytoplasma group, the most commonl y occurring phytoplasma group in Australia, did not amplify rDNA from the S GP and SLY phytoplasmas.