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First report of Tomato leaf curl Karnatka virus infecting
soybean in India
S.K. Raj1*, M.S. Khan1, S.K. Snehi1, S.
Srivastava2 and H.B. Singh2
1 Molecular Virology and 2 Plant Pathology, National Botanical Research
Institute, Lucknow-226001, U.P., India
*skraj2@rediffmail.com Accepted
for publication 09/03/06
During a survey in September 2005, a leaf crumple disease of soybean
(Glycine max) was observed in Lucknow with a disease incidence of
more than 80%. The diseased plants exhibited severe yellowing, crumpling
and distortion of leaves. The infected plants remained dwarf with fewer
flowers which resulted in a very low yield. The causal pathogen was
suspected to be a begomovirus due to the large population of whitefly (Bemisia
tabaci; the vector of begomoviruses) observed on the crop. 
Figure 1: Severe yellowing, crumpling and distortion symptoms on
naturally infected soybean (Glycine max) leaves
The presence of a begomovirus was detected by PCR using begomovirus
coat protein gene-specific primers (Singh, 2005) and total DNA isolated
from infected leaf tissues. An amplicon of the expected size (~800 bp)
was obtained only from leaf samples with symptoms. The PCR product was
cloned, sequenced and the 771 bp sequence data was submitted to Genbank
(accession number DQ343284). Analysis of nucleotide sequence data by
Blast search revealed the highest nucleotide sequence identity (96-98%)
with Tomato leaf curl Karnataka virus (ToLCKV) [TLU38239,
AJ810342, AY753203, AJ810370 and AJ810347]. These results indicated that
the virus of soybean is an isolate of ToLCKV. Mungbean yellow
mosaic India virus (Usahrani, et al., 2004) and
Pepper golden mosaic virus (Mendez-Lozano et al., 2006) have
been reported on soybean from India and Mexico respectively. However,
ToLCKV infection of soybean in India has not been report previously.
References
Mendez-Lozano J, Quintero-Zamora E, Barbossa-Jasso MP, Leyva-Lopez
NE, 2006. A begomovirus associated with leaf curling and chlorosis of
soybean in Sinaloa, Mexico is related to Pepper golden
mosaic virus. Plant Disease 90, 109.
Singh R, 2005. Molecular Characterization of a virus causing yellow
mosaic disease in Cucurbita maxima and development of diagnostics
for detection of the virus. Lucknow, India: University of Lucknow, PhD
thesis.
Usharani KS, Surendranath B, Haq QMR, Malathi VG, 2004. Yellow mosaic
virus infecting soybean in Northern India is distinct from the species
infecting soybean in southern and western India. Current Science 86,
845-850.
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