N. Verma, V. Hallan, R. Ram and A.A. Zaidi*
Plant Virus Laboratory, Floriculture Division, Institute of Himalayan Bioresource Technology, Palampur-176061, Himachal Pradesh, India
Accepted: 27 May 2002
Begonia (family Begoniaceae), a pot plant, vegetatively propagated through cuttings, has been reported to be susceptible to four main viruses viz. Cucumber mosaic virus (CMV), Impatiens necrotic spot virus (INSV), Tobacco necrosis virus (TNV) and Tomato spotted wilt virus (TSWV). Apart from these four, Arabis mosaic virus (AMV), Broad bean wilt virus 1 (BBWV 1) and Carnation mottle virus (CarMV) have also been reported from begonia (Albouy, 1995). Prunus necrotic ringspot virus (PNRSV), an ilarvirus occurs worldwide in cultivated stone fruits (Prunus sp.). Though its host range is wide, it has not previously been reported in begonia from anywhere in the world.
During a survey in and around Palampur, India, in 2001, begonia (Begonia semperflorens) plants were observed showing characteristic ring symptoms on leaves (Fig 1). A total of 30 plants were collected, both symptomatic and those without symptoms, in order to analyse the causal agent. Mechanical inoculation from infected leaves to healthy begonia plants produced characteristic rings and to Cyamopsis tetragonoloba dark coloured local lesions, typical of PNRSV (Brunt et al., 1996). The leaves from infected begonia were processed for total RNA extraction. Total RNA was isolated from 100 mg fresh leaf tissue using QIAGEN RNeasy plant mini kit, according to the manufacture's instructions. RT-PCR was performed using PNRSV specific primers as described by Spiegel et al. (1996).
RT-PCR amplified a c. 785 bp fragment (Fig.2) as expected (Spiegel et al., 1996), indicating the presence of PNRSV in begonia. Amplified fragments can be seen in lanes 3 and 5 (infected begonia samples), while nothing was amplified from symptomless begonia samples (lanes 1, 2, 6, 7 and 8). Since it was difficult to obtain virus free begonia, RNA isolated from healthy Nicotiana tabacum was used as a negative control. No PCR products were amplified from this sample (result not shown).
This is the first report of PNRSV from Begonia.
Albouy J, 1995. Begonia. In: Loebenstein G, Lawson RH, Brunt AA, eds. Virus and virus - like diseases of bulb and flower crops. Chichester, UK: John Wiley & Sons, 449-454.
Brunt AA, Crabtree K, Dallwitz MJ, Gibbs AJ, Watson L, eds 1996. Viruses of Plants. Wallingford, UK: CAB International, 1047-1049.
Spiegel S, Scott SW, Bowman-Vance V, Tam Y, Galiakparov NN, Rosner A, 1996. Improved detection of prunus necrotic ringspot virus by the polymerase chain reaction. European Journal of Plant Pathology 102, 681-685.
©2002 The Authors