Arch Virol (2005) 150: 2101–2108
Identiﬁcation of a second begomovirus, Sri Lankan cassava
mosaic virus, causing cassava mosaic disease in India
, R. W. Briddon
, and I. Dasgupta
Department of Plant Molecular Biology, University of Delhi South Campus,
New Delhi, India
Department of Disease and Stress Biology, John Innes Centre, Norwich, U.K.
Received November 19, 2004; accepted May 10, 2005
Published online June 28, 2005
Summary. The DNA A and DNA B components of a begomovirus associated
with cassava mosaic disease (CMD) originating from Kerala, India, were cloned.
Biolistically inoculated clones induced symptoms typical of CMD in cassava.
Sequence comparisons showed the virus to be an isolate of Sri Lankan cassava
mosaic virus (SLCMV). This is the ﬁrst time this begomovirus species has been
identiﬁed in India and only the second species shown to cause CMD in the
country. The implication of these ﬁndings on our understanding of the diversity
and geographic distribution of CMD-associated begomoviruses in the region and
on efforts to obtain resistance to CMD are discussed.
Cassava, Manihot esculenta Crantz, is cultivated for its starch-containing, tuber-
ous roots and is consumed by over 500 million people worldwide. It represents
the third most important source of dietary calories after cereals and legumes .
Cassava mosaic disease (CMD) is widespread in Africa and the Indian subconti-
nent and represents one of the major constraints to the cultivation of this important
crop [11, 17]. CMD is caused by viruses of the genus Begomovirus (family
Geminiviridae) which are transmitted, plant-to-plant, exclusively by the whiteﬂy
Bemisia tabaci. Like the majority of begomoviruses, the viruses causing CMD
have genomes comprising two circular, single-stranded DNA components. These
are designated as DNA A and DNA B and possess a segment of high sequence
similarity (∼200 nucleotides in length) known as the common region (CR).
The CR harbours the viral promoters, origin of replication and sequences in-
volved in binding of the DNA A-encoded replication associated protein (Rep), the