ORIGINAL ARTICLE A Leaf Curl Disease in Germplasm of Rapeseed-Mustard in India: Molecular Evidence of a Weed-Infecting Begomovirus–Betasatellite Complex Emerging in a New Crop Anirban Roy 1 , Poreddy Spoorthi 1 , Manas Kumar Bag 1 , Telaprolu Venkata Prasad 1 , Ranbir Singh 1 , Manoranjan Dutta 1 and Bikash Mandal 2 1 Germplasm Evaluation Division, National Bureau of Plant Genetic Resources, New Delhi, 110012, India 2 Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012, India Keywords Betasatellite, Brassica spp., Croton yellow vein mosaic virus, India, Phylogenetic analysis, Rolling circle amplification Correspondence A. Roy, National Bureau of Plant Genetic Resources, New Delhi, India. E-mail: anirbanroy75@yahoo.com Received: January 10, 2013; accepted: February 26, 2013. doi: 10.1111/jph.12102 Abstract Evaluation of 130 accessions of rapeseed-mustard germplasm grown at the National Bureau of Plant Genetic Resources, New Delhi, India during the winter season (2011–2012) revealed the occurrence of a leaf curl dis- ease in seven accessions. The occurrence of the disease was observed in another 62 of 525 accessions evaluated during 2012–2013. The association of a monopartite begomovirus and betasatellite was established with the symptomatic plants by whitefly transmission and PCR amplification. The complete nucleotide sequences of the begomovirus (JX270684, 2745 nucleotides), obtained by rolling circle amplification, showed the highest sequence identity (98.1%) with the weed-infecting begomovirus, Croton yellow vein mosaic virus. Analysis of recombination indicated the probable occurrence of many overlapping inter- and intraspecific recombination events. The sequence of betasatellite (JX270685, 1355 nucleotides) showed the highest sequence identity (95.7%) with Croton yellow vein mosaic betasatellite. Begomoviruses were not previously known to naturally infect rapeseed-mustard. This is the first report of the emergence of a weed-infecting begomovirus–betasatellite complex in rapeseed-mustard germplasm in India and raises the concern on utilization of such suscepti- ble germplasm in crop improvement programmes. Introduction Rapeseed-mustard (Brassica spp.; Brassicaceae) are the important crops grown worldwide for oilseed, condiments, vegetable and fodder crops. India is the third largest rapeseed-mustard producer in the world. Mustard is the second important edible oil- seed after groundnut sharing 27.8% in India’s oil- seed economy (Chand et al. 2004). Of different viruses, Beet western yellows virus and Turnip mosaic virus cause significant economic losses in a wide range of cultivated mustard species (Edwardson and Christie 1991; Shattuck 1992). Of the gemin- iviruses, Cabbage leaf curl virus (CLCV) was experi- mentally shown to infect a wide range of plants within the Brassicaceae, including cabbage, cauliflower, mustard and Arabidopsis (Strandberg et al. 1991). No leaf curl disease or any gemini- virus have previously been reported to infect rape- seed-mustard crops under natural conditions. Geminiviruses have monopartite or bipartite circular single-stranded DNA (ssDNA) genomes encapsidated within geminate particles. The family Geminiviridae is composed of four genera, Begomovirus, Mastrevirus, Curtovirus and Topocuvirus distinguished by their host range, insect vector and genome organi- zation (Harrison 1985). Begomoviruses generally have bipartite genomes (designated as DNA-A and DNA-B), are transmitted by whiteflies (Bemisia tabaci Genn.) (Hemiptera: Aleyrodidae) and infect dicotyle- J Phytopathol 161 (2013) 522–535 Ó 2013 Blackwell Verlag GmbH 522 J Phytopathol