P-56. Natural occurrence of a Begomovirus associated with leaf curl disease of Mentha in India

Mint (Mentha viridis; family Labiateae) is grown as an important essential oil bearing industrial crop in India, with more than 2,50,000 ha land under cultivation. Several viruses cause important diseases on Mentha, currently a Begomovirus was detected from M. viridis. During May-June, 2005, viral like disease was found to reduce the biomass of Mentha drastically. The most common symptoms encountered were foliar rugosity, light yellow spot, upward curling and retarded growth. The disease incidence ranged 40–60% of plant population. Leaves having visual symptoms and apparently without symptoms were tested for virus infection by transmission electron microscopy, for whiteflies transmission and polymerase chain reaction (PCR) mediated Begomovirus specific amplification. The disease was transmitted from naturally infected Mentha to healthy seedlings by whiteflies (Bemisia tabaci) but not by mechanical or aphid transmission. Total genomic DNA extracted from symptomatic/asymptomatic samples collected from different locations of the fields. The presence of a Begomovirus was confirmed by PCR amplification using a pair of primers. An amplification product of the expected size (approx. 771 bp) was produced from symptomatic samples but no amplification in symptom less plant. Cloning of the PCR product was performed in the TOPO TA kit. Sequence analysis revealed the highest nucleotide sequence identities (99–100%) of the virus infecting M. viridis with Whitefly-transmitted Indian Begomovirus from Tabernaemontana divaricata (DQ 339124.1) and Pepper leaf curl virus from soybean (DQ 343285.2). This is the first occurrence of a Begomovirus associated with leaf curl disease of Mentha viridis from India.