MOLECULAR CHARACTERIZATION OF A Tospovirus INFECTING BELL PEPPER (Capsicum annuum L.)
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Date
2015
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UHF,NAUNI
Abstract
ABSTRACT
Surveys conducted during the present investigations revealed the presence of ringspot disease
in bell pepper growing areas of Solan district of Himachal Pradesh with disease incidence ranging
between 5 percent to 51percent during the cropping seasons of 2013 and 2014. The causal virus was
characterized on the basis of symptomatology, transmission, host range, serology and molecular
studies. Infected bell pepper plants exhibited ringspot symptoms of variable sizes on the leaves which
coalesced later on covering the entire leaf lamina and in some cases rings turning necrotic were also
observed. Infected bell pepper fruits developed pale yellow, red and green ringspots. Symptomatic
plants were collected and sap inoculated to healthy bell pepper plants. Samples from Khaltoo and
Pandah yielded strong positive reaction when subjected to DAS-ELISA against Tospo (I, II, III)
antisera. Transmission studies revealed that virus isolates were transmissible through sap but not
through seed. Studies on indicator hosts established Nicotiana tabaccum var. White Burley and
Nicotiana glutinosa to be the best indicator hosts for maintaining virus cultures round the year.
Studies on the host range revealed that out of six families tested namely Chenopodiaceae, Cruciferae,
Cucurbitaceae, Leguminosae, Malvaceae and Solanaceae, only members of family Cruciferae and
Malvaceaeremained uninfected on sap inoculation however, other hosts variably produced localized
and systemic symptoms. Serological assay of weed hosts revealed that Amaranthus sp. and Datura sp.
to be the possible reservoir hosts of the causal virus. Infected tomato fruits growing in the vicinityof
infected bell pepper fields however, yielded negative results in DAS-ELISA but RT-PCR based
detection revealed clear association of causal virus with tomato. RT-PCR based detection,
nucleocapsid (N) gene sequencing and BLASTN analysis of bell pepper virus isolates revealed that
the virus associated with ringspot disease of bell pepper in Himachal Pradesh was Capsicum chlorosis
virus, a member of genus Tospovirus.
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