Molecular detection and identification of phytoplasma associated with pepper witches’ broom in China

Pepper witches’ broom (PWB) disease was observed in a field in Yangling, Shaanxi Province, China. The result of mechanical inoculation test for this disease was negative. Phytoplasma-like bodies were observed in ultrathin sections of petiole tissues of symptomatic samples. 16S rRNA gene and tuf gene of phytoplasma were amplified from the total DNA of symptomatic samples. Phylogeny analysis of the 16S rRNA gene and tuf gene suggested that the pepper witches’ broom associated phytoplasma belongs to the subgroup 16SrI-B, which was confirmed by the RFLP analysis of the 16S rRNA gene. The phytoplasma subgroup 16SrI-B was also detected in the vector Cicadella viridis trapped from the infected field. To our knowledge, this is the first report of 16SrI-B phytoplasma causing pepper witches’ broom in China.