Molecular detection of ‘Candidatus Phytoplasma australasiaticum’ and ‘Ca. P. trifolii’ in grapevine in India

Grapevine cultivation is one of the most remunerative farming enterprises in India. Grapevine phytoplasma-associated disease has been noticed in several districts of Maharashtra, Jammu and Kashmir and Northeastern state of India in recent years. Field surveys in 2023–2024 across five major states including Maharashtra, Andhra Pradesh, Telangana, Mizoram and Karnataka revealed the incidence of grapevine phytoplasma disease ranging from 12–18% on the basis of phytoplasma symptoms. These were yellowing, reddening and rolling of leaf margins and were observed in different grapevine varieties. The phytoplasma presence was assayed employing universal and specific phytoplasma nested primer pairs, P1/Tint and 3F/3R which yielded 1.3 kb amplicons from all the symptomatic grapevine samples collected. The BLAST analysis of 16Sr RNA gene sequences shared higher sequence identity with ‘Candidatus Phytoplasma australasiaticum’ and ‘Ca. P. trifolii’. The phylogeny confirmed the presence of strains related to ‘Ca. P. australasiaticum’ (16SrII-D) and ‘Ca. P. trifolii’ (16SrVI-D).