Geminivirus isolates associated with the epidemic of severe cassava mosaic disease in Uganda were studied and compared with virus isolates from the part of Uganda outside the epidemic area, and with African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV). Isolates of a novel type [the Uganda variant (UgV)] were detected in severely affected plants from the epidemic are...

The complete nucleotide sequence of the DNA of Indian cassava mosaic virus (ICMV) and a key part of that of a group B isolate of African cassava mosaic virus from Malawi (ACMV-M) were determined and compared at the nucleotide and encoded amino acid levels with the published sequences of an ACMV group A isolate (ACMV-K) and other whitefly-transmitted gemini-viruses (WTGs). The DNA of ICMV consis...

Posttranscriptional gene silencing (PTGS) in plants is a natural defense mechanism against virus infection. In mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. Synergistic severe mosaic disease caused by simultaneous infection with isolates of the Cameroon strain of African cassava mosaic virus (ACMV-[CM]) and East African ca...

Two types of geminate structures were purified from African cassava mosaic geminivirus (ACMV)-infected Nicotiana benthamiana plants and analyzed by electron cryomicroscopy and image reconstruction. After cesium sulfate density gradient centrifugation, they were separated into lighter top (T) and heavier bottom (B) components. T particles comigrated with host proteins, whereas B particles were c...

Cassava mosaic disease (CMD), caused by an array of is the most economically important viral disease of cassava in sub-Saharan Africa. The most frequently reported in West Africa are African cassava mosaic virus (ACMV) and East African cassava mosaic Cameroon virus (EACMCV). In this study, 42 cassava leaves and 30 symptomatic weeds belonging to the Asteraceae, Cucurbitaceae and Leguminosae fami...

Small insertions were made independently at each of four unique restriction sites on African cassava mosaic virus (ACMV) DNA A to disrupt the three overlapping complementary-sense open reading frames (ORFs) herein designated AC1, AC2 and AC3. The DNA A mutants were assayed for their infectivity by agroinoculation of monomeric constructs to Nicotiana benthamiana plants containing chromosomal ins...

Two bipartite begomoviruses, Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV), have been isolated from mosaic-diseased cassava originating from central India and Sri Lanka, respectively. ICMV was transmitted with low efficiency from cassava to Nicotiana benthamiana by sap inoculation to give leaf curl symptoms. SLCMV was much more virulent in this host, producing s...

Cassava mosaic disease (CMV), caused by one or a combination of cassava mosaic geminiviruses, is ranked among the most important constraints to profitable and efficient production of cassava. Effective control measures require in-depth knowledge of the viral causative agent. Using rolling-circle amplification and unique enzymes, the full genome of two species of cassava mosaic geminivirus isola...

We have analysed DNA from African cassava mosaic virus (ACMV)-infected Nicotiana benthamiana by two-dimensional agarose gel electrophoresis and detected ACMV-specific DNAs by blot-hybridisation. ACMV DNA forms including the previously characterised single-stranded, open-circular, linear and supercoiled DNAs along with five previously uncharacterised heterogeneous DNAs (H1-H5) were resolved. The...

Cassava mosaic disease caused by cassava begomoviruses (CMBs) remains one of the major constraints to production since it causes yield losses up 100%. Researches showed that some CMBs infecting plants may be coming from non-crop plants. This study intended identify and characterize isolated plant species in Unguja Pemba Islands. A total 108 viral symptomatic asymptomatic leaf samples were colle...