Isolation and Characterization of a Geminivirus Causing Yellow Mosaic Disease of Horsegram (Macrotyloma uniflorum [Lam.] Verdc.) in India*

Abstract

Horsegram yellow mosaic disease was shown to be caused by a geminivirus; horsegram yellow mosaic virus (HYMV). The virus could not be transmitted by mechanical sap inoculation. Leaf dip and purified virus preparations showed geminate virus particles, measuring 15‐18 * 30 nm. An antiserum for HYMV was produced and in enzyme‐linked immunosorbent assay (ELISA) and immunosorbent electron microscopy (ISEM) tests HYMV was detected in leaf extracts of fieldinfected bambara groundnut, french bean, groundnut, limabean, mungbean, pigeonpea and soybean showing yellow mosaic symptoms. Bemisia tabaci fed on purified HYMV through a parafilm membrane transmitted the virus to all the hosts listed above but not to Ageratum conyzoides, okra, cassava, cowpea, Croton bonplandianus, Lab‐lab purpureus, Malvastrum coromandalianum and tomato. No reaction was obtained in ELISA and ISEM tests between HYMV antibodies and extracts of plants diseased by whitefly‐transmitted agents in India such as A. conyzoides yellow mosaic, okra yellow vein mosaic, C. bonplandianus, yellow vein mosaic, M. coromandalianum yellow vein mosaic, tomato leaf curl and cassava mosaic. HYMV was also not found to be related serologically to bean golden mosaic, virus.

Characterization of a begomovirus causing horsegram yellow mosaic disease in India

“…Isolation, purification, electron microscopic and serological studies of HgYMV have been reported (Muniyappa et al 1987). However, the present study is the first report of the molecular characterization of the genome components of HgYMV.…”

“…Later preliminary electron microscopic studies revealed geminate particles (Muniyappa et al 1987) from the infected leaves. Swanson et al (1992) showed that monoclonal antibodies raised against African cassava mosaic virus It had been established that ori is a hot-spot for recombination (Stanley 1995).…”

Purification and Characterization of Indian Cassava Mosaic Virus

“…Virus purification: IGMV was purified from infected cassava or N. benthamiana leaves using a method described by GOODMAN et al (1977) and MUNIYAPPA et al (1987) with some modifications. Leaves from N. benthamiana were harvested 12-15 days after inoculation and homogenized in 0.1 M sodium phosphate buffer, pH 7.8 (2 ml/g) containing 1 % 2-mercaptoethanol, 0.001 M cysteine hydrochloride, 0.01 M sodium EDTA and chloroform (1 ml/g).…”

Tropical Food Legumes

“…YMD was characterized by yellow mosaic on leaves, coupled with reduction of leaf size and plant height in severely infected plants. This virus was initially identified as HgYMV (Muniyappa, Rajeshwari, Bharathan, Reddy, & Nolt, 1987). In addition to horse gram, HgYMV infects French bean, groundnut, lima bean, mungbean, pigeonpea, soybean and bambara groundnut in India.…”