March 10, 2006
From: ProMED-mail<promed@promedmail.org>
Source: British Society for Plant Pathology, New Disease Reports, Vol. 13 [edited] <http://www.bspp.org.uk/ndr/july2006/2006-17.asp>

First report of Tomato leaf curl Karnatka virus infecting soybean in India
S.K. Raj(1), M.S. Khan(1), S.K. Snehi(1), S. Srivastava(2) and H.B. Singh(2)
1 Molecular Virology and 2 Plant Pathology, National Botanical Research Institute, Lucknow-226001, U.P., India
Accepted for publication 9 Mar 2006

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 percent. 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 [see link for picture]

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 (approx. 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 percent) 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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ProMED-mail
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[The crop plant soybean (_Glycine max_) is susceptible to leaf crumple disease in India, shown here to be caused by tomato leaf curl Karnataka virus (ToLCKV), a begomovirus (family: _Geminiviridae_, genus: _Begomovirus_). An incidence of more than 80 percent was observed in Lucknow. Diseased plants exhibited severe yellowing,
crumpling and distortion of leaves. Infected plants were stunted, and had a very low yield. The virus is not uncommon in solanaceous crops like tomato in India (note "see also:"), but detection in soybean is a 1st report. The complexity of different begomoviruses in India and neighboring countries that cause similar diseases can be followed in the posts listed below. Diversity is driven by an abundant active vector, the whitefly _Bemisia tabaci_, many weed and crop reservoirs, and the capacity for this group of ssDNA viruses to share/swap genetic information thereby creating new viruses and strains. Their ability to cause severe disease is demonstrated in this report.

Map: Lucknow, India
<http://www.tageo.com/index-e-in-v-36-d-m2919422.htm>

Pictures: see link to article

Links:
Includes virus distribution map
<http://gemini.biosci.arizona.edu/viruses/tolckv/index.htm>
- Mod.JAD]

[see also in the archive:
Yellow leaf curl, tomato - Multicountry: 1st reports 20060304.0702
2005
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Bell pepper leaf curl virus - Pakistan (Lahore) 20051022.3084
Tomato leaf curl New Delhi virus, chili - India 20050712.1984
Tomato leaf curl virus - Bangladesh 20050608.1593
Tomato leaf curl virus, New Delhi strain - India 20050603.1548
2004
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Tomato leaf curl virus, chilli pepper - Pakistan 20040509.1255
2003
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Tomato leaf curl virus, potato - India: first report 20031001.2470
Leaf curl, tomato - India (Uttar Pradesh) 20030222.0455
Begomoviruses, chili pepper, tomato - Asia 20030221.0450
2001
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Tomato leaf curl begomovirus, tomato disease - India (02) 20010402.0663
Tomato leaf curl begomovirus, tomato disease - India 20010331.0649]