Phytopathogenic Mollicutes

Phytoplasma suspected symptoms of witches’ broom, leaf yellowing, stunting and little leaf were observed in China rose, petunia, Dianthus and ornamental kale during surveys in flower nurseries and experimental ornamental fields at Punjab Agricultural University, Ludhiana, Punjab and Rohtak, Haryana, India in March 2017. To investigate the phytoplasma presence, PCR assays were performed using universal primer pairs specific to the phytoplasma 16Sr RNA gene. Direct PCR amplification with P1/P7 primer pair did not yield expected product from any of the four ornamental plant samples but amplification of about 1.3 kb DNA bands was observed using universal primer pair R16F2n/1492R in nested PCR. Pair wise sequence comparison, phylogeny and virtual RFLP analysis of 16S rDNA sequences confirmed the presence of two phytoplasma groups (16SrI and 16SrII) in the studied ornamental plants species. ‘Ca. P. australasia’, subgroup 16SrII-D, was confirmed in Petunia and Dianthus showing leaf yellowing, and in ornamental kale samples showing witches’ broom and stunting at Ludhiana. China rose leaf yellowing and stunting at Haryana, was associated to a strain related to 16SrI-B phytoplasmas. The detection of 16SrII-D subgroup phytoplasmas in ornamental kale and in Dianthus are is a new report in the world.