Natural Occurrence of Cucumber mosaic virus on Rauvolfia serpentina, A New Record

Rauvolfia serpentina, family Apocynaceae, is widely cultivated in India and adjoining countries for the production of roots used in several herbal formulations (1). Severe mosaic and stunting of the whole plant was observed on R. serpentina growing in experimental plots of NBRI, Lucknow, in 2006. The causal pathogen was transmitted by sap inoculation on Nicotiana tabacum cv. White Burley, N. rustica, and N. glutinosa, which produced necrotic local lesions and systemic mosaic. The virus reacted positively with antiserum of Cucumber mosaic virus (CMV; PVAS 242a, ATCC, Manassas, VA) in gel double diffusion tests, indicating the presence of CMV. Total RNA was isolated from infected and healthy leaf tissues of R. serpentina, and reverse transcription (RT)-PCR was performed using CMV specific primers AM180922/AM180923. RT-PCR resulted in an expected size (~650 bp) amplicon in infected but not healthy samples. The amplicon was cloned, sequenced, and the data was submitted to GenBank (Accession No. DQ914877). BLAST search analysis of the virus isolate showed highest (99%) sequence identity with CMV isolates (GenBank Accession Nos. DQ640743, AF350450, X89652, and AF281864). The virus isolate showed a close phylogenetic relationship with Indian isolates of CMV belonging to subgroup IB. A literature survey revealed that there is no report of occurrence of any virus on R. serpentina except some fungal infections (2). To our knowledge, this is the first record of natural occurrence of CMV on R. serpentina. References: (1) Anonymous. Wealth of India 8:376, 1969. (2) R. S. Shukla et al. EPPO Bull. 36:11, 2006.