First report of association of ‘Candidatus Phytoplasma asteris’ (16SrI group) with little leaf disease of rose (Rosa alba) in India

Rose (Rosa alba) is grown in Gorakhpur, India, for ornamental and essential oil extraction purposes. Symptoms of little leaf disease, yellowing and shortening of internodes were observed in different rose gardens during June 2008 (Fig. 1). Leaf samples from four symptomatic and asymptomatic plants were collected. Total DNA was extracted and assayed for phytoplasma 16S rRNA in a direct polymerase chain reaction (PCR) using universal primers PI/P6, followed by a nested PCR with R16F2n/R16R2 primers, yielding amplicons from only the symptomatic samples (Fig. 2).

Three nested PCR amplicons were cloned (pGEM-T Easy Vector, Promega), sequenced, and the consensus sequence deposited in GenBank (Accession No. FJ429364). BLAST analysis revealed the highest identity (99%) of the R. alba little leaf phytoplasma with those of group 16SrI ‘Ca. Phytoplasma asteris’, confirmed by phylogenetic analysis (MEGA 4.0) (Fig. 3).

The group 16SrI has been reported from rose in China (Gao et al, 2008), and has impacted in India since its record in sesame (Khan et al, 2007) and desert rose (Adenium obesum) (Raj et al, 2007). However, this is the first report of a ‘Ca. Phytoplasma asteris’-related strain affecting R. alba in India.