Abstract:
Emergence of begomoviruses is one of the biggest limitation to the cultivation
and production of crops in different countries including Pakistan. Pakistan being an
agriculture country is very important for the production of wheat and cotton, and cotton
is the widely grown crop in the areas of Punjab and Sindh Province. Pakistan is the
fourth largest grower of cotton. The main threat to cotton production is CLCuD, caused
by a complex of begomoviruses with a single known betasatellite (CLCuMB).
Identification of begomoviruses on weeds and fruit plants is important to detect because
these are alternative hosts and may provide shelter and inoculum source to other field
crops. Begomovirus belongs to family Geminiviridae and transmits through white fly
(Bemisia tabaci). Leaf samples of four different plants Duranta (Duranta erecta), Black
nightshade (Solanum nigrum), Papaya (Carica papaya) and Granda (Carissa opaca)
showing leaf curl and mosaic symptoms were collected from different areas of
Faisalabad in 2015. Total DNA was extracted from symptomatic leaf samples by CTAB
method. The DNA was subjected to PCR and expected band size (approx. 2.8 kb) was
obtained by using a set of abutting primers. Attempts to identify the presence of
betasatellite in the infected samples by using universal betasatellite primers
(Beta01/Beta02) produced an approximately 1.3 kb product. DNA B was also
identified in Papaya by using KTBF/KTBR and produced an approximately 2.8 kb
product. Partial nucleotide sequence of DNA B from papaya showed 95% sequence
identity with Tomato leaf curl New Delhi virus (ToLCNDV) and betasatellite from
Black nightshade showed 93%identity with Cotton leaf curl Multan betasatellite
(CLCuMB). Granda belongs to family Apyocynaceae, which shows that begomovirus
not only effects solanaceae family but also non solanaceous hosts. Begomovirus was
isolated first time from Granda plant. Isolation of begomovirus from alternative hosts
is important because they provide shelter for recombination during the off-season.
