Yellow leaf curl disease
of pumpkin in Thailand is associated with Squash leaf curl
China virus
T. Ito1, T. Ogawa1,
K. Samretwanich2, P. Sharma1 and
M. Ikegami1*
1 Department
of Life Science, Graduate School of Agricultural Science, Tohoku University,
1-1, Tsutsumidori-Aamamiyamachi, Aoba-ku, Sendai, Miyagi 981-8555, Japan
2
National Research Council of Thailand, 196 Phaholyothin Road, Chatuchak,
Bangkok 10900, Thailand
*ikegami@bios.tohoku.ac.jp Accepted for publication 09/10/07
Yellow leaf curl disease causes heavy losses to cucurbit crops in Thailand.
Previously, we have detected Tomato leaf curl New Delhi virus from
infected cucumber (Cucumis sativus), wax gourd (Benincasa hispida),
cantaloupe (Cucumis melo) and muskmelon (Cucumis melo) plants in
Thailand (Samretwanich et al., 2000a, b). Pumpkin (Cucurbita pepo)
is also severely affected by this disease.
Three pumpkin plants exhibiting leaf curling
and yellowing symptoms (Fig.1) were collected from Kamphaensaen, Nakom Pathom in
Thailand during 2001.
Figure 1:
Leaf
curling and yellowing symptoms of infected pumpkin originating from
Thailand
infected with
Squash leaf curl China virus.
Total
DNA was extracted from leaves and PCR was conducted using begomovirus specific
degenerate primers UPV1 and UPC2 designed to amplify DNA-A (Briddon and Markham,
1994). A PCR product of approximately 2.7kbp was obtained, cloned and sequenced.
To obtain the full DNA A sequence a
pair of degenerate primers with an XbaI site (underlined) were designed
to the partial sequence (virion-sense primer 5′-TCTAGAACGTCTCCGTCTTTG-3′;
complementary-sense primer 5′-TCTAGAAATGGGGTGTTTTCC-3′) and used in
PCR
to amplify a product of approximately 2.8kbp, which was cloned and sequenced
(2736nt, Accession No. AB330078). Efforts to detect DNA-B component associated
with the virus by PCR using primers PCRc1 and PBL1v2040
(Rojas et al., 1993) were unsuccessful. The DNA-A contained the five open
reading frames typical of begomoviruses, two in the virion sense and three in
the complementary sense. Comparison of the complete nucleotide sequence of this
begomovirus with those of full-length begomoviral DNA-As available in GenBank
showed the highest nucleotide sequence identity (95 and 89%) with Squash leaf
curl China virus (SLCCNV, Accession No. AB027465) and Squash leaf curl
Philippines virus (SLCPHV; Accession No. AB085793), respectively. For ORF V1
(coat protein), this begomovirus had the highest amino acid sequence identity
with its counterparts in SLCCNV (97%) and SLCPHV (97%). Therefore the present
virus is an isolate of SLCCNV, which we designate SLCCNV-Thailand.
This
is a first report of SLCCNV infecting pumpkin in Thailand.
Acknowledgements
This work was partly supported by the Grant-in-Aid for Academic Frontier
Promotion programme and Grant-in-Aid for Scientific Research of the Ministry of
Education, Culture, Sports, Science and Technology of Japan.
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