Objective: Jujube witches' -broom (JWB) is an important plant disease caused by phytoplasma. The major objective of our research was to classify JWB in Beijing and Hebei districts and to provide reference for classification in subgroup level.
Methods: By use of PCR, the elongation factor Tu (tuf gene) and ribosomal protein (rp) gene of phytoplasma associated with JWB in Beijing and Hebei districts were amplified separately with universal primer pairs fTufu/rTufu and rp(v)F1A/rp(v) R1A. Partial tuf gene and rp gene were sequenced and similarity analysed with other phytoplasmas.
Results: We obtained partial tuf gene sequence (824bp) and complete rp gene (1196bp) from the diseased sample. In tuf gene, JWB in Beijing shared most similarity (92.84%) with Flavescence dorée (FD) phytoplasma (Candidatus Phytoplasma vitis), however, shared a low similarity (57.29%) with JWB in Shaanxi district which had been already reported. The similarity analysis for sequences of rp gene showed a high identity (> 96%) with members of the 16SrV group phytoplasmas. It shared most identity (99.83%) with JWB strain Taishan and Hemp fiber witches' -broom phytoplasma (HFWB) of the 16SrV group.
Conclusion: The JWB strains in Beijing and Hebei are members of 16Sr V; JWB in Beijing and Hebei share high similarity, and show a diversity with JWB in Shaanxi.