TRENDS IN BIOSCIENCES 6-1, 2013 EDITION

38 Trends in Biosciences 6 (1), 2013
Tabl e 2. Screeni ng of hosts of Begomovirus against Sunflower leaf curl virus
Sl.
No.
Name of the plant species
Family
No. of plants
infected /
No. of plants
inoculated
Transmission
(%)
Incubation
period
(days)
Symptoms
observed
1 Tobacco (Nicotiana benthamiana) Solanaceae 6/10 60.00 22 DCu, RL, St
2 Tomato (Lycopersicon esculentum) Solanaceae 7/10 70.00 21 DCu, Bl, RL, St
3 Zinnia (Zinnia elegans, L.) Asteraceae 6/10 60.00 16 UCu, RL, St
4 Acanthospermum hispidum Asteraceae 5/10 50.00 23 DCu, RL
5 Parthenium (Parthenium hysterophorus) Asteraceae 2/10 20.00 28 DCu, RL, St
6 Euphorbia (Euphorbia geniculata L.) Euphorbiaceae 0/10 0.00 ____ ”
7 Cotton (Gossypium hirusutum.) Malvaceae 0/10 0.00 ____ ”
8 Cucumber (Cucumis sativus) Cucurbitaceae 0/10 0.00 ____ ”
9 Cassia (Cassia sp.) Fabaceae 0/10 0.00 ____ ”
10 Bhendi (Abelmoschus esculentus) Malvaceae 0/10 0.00 ____ ”
11 Pumpkin (Cucurbita sp.) Cucurbitaceae 0/10 0.00 ____ ”
12 Beans (Phaseolus vulgaris) Fabaceae 0/10 0.00 ____ ”
Note: Bl: blistering; UCu: upward curling; DCu: downward curling; Vt: Vein thickening; RL: reduction of leaf size; SI: shortening of internodes;
St: stunting
100% with 20 whiteflies per plant. This indicates that the
number of insects and the transmission efficiency was
positively correlated (Fig.1). Low transmissibility of Indian
Cassava Mosaic Virus (ICMV) associated with woody plant
species like cassava was reported to be only 18.7% with 50
whiteflies per plant respectively (Mathew, 1988).
In order to identify the natural hosts and weeds, the
virus was inoculated to different plant species through
whitefly (Table 2). Of the 12 plant species inoculated through
whiteflies, successful transmission of virus was obtained only
with Nicotiana benthamiana (Fig. 2a), Lycopersicon
esculentum (Fig. 2b), Zinnia elegans (Fig. 2c),
Acanthospermum hispidum (Fig. 2d), and Parthenium
hysterophorus (Fig. 2e), The common symptoms observed
on host plants are leaf curling, reduction in the leaf size and
stunting of plants. Euphorbia geniculata, Gossypium
barbadense, Cassia sp., Cucumis sativus, Abelmoschus
esculentus, Cucurbita moschata and Phaseolus vulgaris did
not show any visible symptoms.
Host range studies revealed that the virus was limited
to the only few plant species belonging to Solanaceae and
Asteraceae. Out of 12 plant species inoculated, two plant
species belonging to Solanaceae viz., N. tabacum, L.
esculentum were infected with SuLCV. Three plant species,
Zinnia elegans, Acanthospermum hispidum and Parthenium
hysterophorus belonging to Asteraceae were infected with
SuLCV through whiteflies and expressed the systemic
symptoms within 30 days. Begomovirus specific primers
(Deng, et al., 1994) were used to confirm infection by SuLCV
in Nicotiana benthamiana, Lycopersicon esculentum, Zinnia
elegans, Acanthospermum hispidum and Parthenium
hysterophorus by amplifying ~530 bp of core region of CP
gene. These primers used elsewhere, successfully detected
Croton leaf curl virus (CrLCuV) (Mahesh, et al., 2010), Cotton
leaf curl Multan virus-Hibiscus [Bangalore]
(CLCuMVHib[Ban]) (Rajeshwari, et al., 2005), ( Zinnia leaf
curl virus (ZLCV) (Shivakumar, 2010) and Jatropha Mosaic
Virus (Rangaswamy, et al., 2005; Aswathanarayana, et al.,
2007).
Fig. 2. (a-e). Screening of hosts of Begomovirus against Sunflower leaf
curl virus