Sweet potato little leaf strain V4 phytoplasma associated with snake bean in the Northern Territory, Australia

Abstract

Sweet potato little leaf strain V4 phytoplasma (SPLL-V4) was found to be associated with 12-week old snake bean plants (Vigna unguiculata ssp. sesquipedalis) from a block with 890 plants in Lambells Lagoon, Northern Territory. Symptoms included witches’ broom, big bud, phyllody and little leaf. There was a 19.9 % incidence of symptoms on 366 plants assessed. The same phytoplasma was also detected from a single plant of Phyllanthus amarus with witches’ broom symptoms growing near the snake bean plants. The SPLL-V4 phytoplasma was identified based upon the 16S ribosomal RNA gene and intergenic spacer region nucleotide sequence and restriction fragment length polymorphism.