Bitter gourd and bottle gourd—new natural hosts of Candidatus Phytoplasma trifolii (16SrVI-D)

Symptoms such as phyllody, reduced size of leaves and shortened internode length were observed in bitter gourd, while phyllody symptoms were recorded in bottle gourd crops cultivated in fields at Pune, Maharashtra, India. Symptomatic leaf petiole samples of both the crops were analysed for phytoplasma association by nested PCR which yielded ~1.2 kb amplicons using universal primers specific to phytoplasmas. BLASTn analysis of the amplicons revealed that the consensus sequences shared 99–100% identity with phytoplasmas belonging to 16SrVI group, allowing their identification as a ‘Candidatus Phytoplasma trifolii’ -related strain. Virtual restriction fragment length polymorphism analysis of 16SrRNA encoding sequences classified the phytoplasmas into the 16SrVI-D subgroup. This is the first record of ‘clover proliferation’ phytoplasma subgroup D associated with bitter gourd and bottle gourd worldwide.