Genetic analysis of maize streak virus isolates from Uganda reveals widespread distribution of a recombinant variant

Abstract

Maize streak virus (MSV) contributes significantly to the problem of extremely low African maize yields. Whilst a diverse range of MSV and MSV-like viruses are endemic in sub-Saharan Africa and neighbouring islands, only a single group of maize-adapted variants -MSV subtypes A 1 -A 6 -causes severe enough disease in maize to influence yields substantially. In order to assist in designing effective strategies to control MSV in maize, a large survey covering 155 locations was conducted to assess the diversity, distribution and genetic characteristics of the Ugandan MSV-A population. PCR-restriction fragment-length polymorphism analyses of 391 virus isolates identified 49 genetic variants. Sixty-two full-genome sequences were determined, 52 of which were detectably recombinant. All but two recombinants contained predominantly MSV-A 1 -like sequences. Of the ten distinct recombination events observed, seven involved inter-MSV-A subtype recombination and three involved intra-MSV-A 1 recombination. One of the intra-MSV-A 1 recombinants, designated MSV-A 1 UgIII, accounted for .60 % of all MSV infections sampled throughout Uganda. Although recombination may be an important factor in the emergence of novel geminivirus variants, it is demonstrated that its characteristics in MSV are quite different from those observed in related African cassava-infecting geminivirus species.

A novel maize-infecting mastrevirus from La Réunion Island

“…Circular viral DNA molecules were amplified from a crude total DNA extract from the two maize samples using Phi29 DNA polymerase (TempliPhi TM , GE Healthcare, USA) as described previously [15,16,18] and cut with KpnI (PR50) and BamHI (PR52) to yield *2.7-kb DNA fragments, which were subsequently ligated to the KpnI and BamHI sites of pGEMZf? (Promega Biotech, USA).…”

Replicative intermediates of maize streak virus found during leaf development

“…After agroinfection of maize with cloned MSV-A DNA (Owor et al, 2007), total nucleic acids were isolated from different sections of leaves five and six, shoot apices and emerging immature leaf laminae and sheaths (Fig. 1a, d).…”

Spatio-Temporal Variations in the Incidence and Severity of Maize Streak Disease in the Volta Region of Ghana

“…The ANOVA also revealed that the overall mean incidence on maize plants growing under tree shades (43.6%) was significantly higher (F=46. 15 In the major season, ANOVA revealed highly significant differences in the severity of MSD in maize plants growing in the open parts of the fields (F=16.75; df=57; P<0.001) and those growing under tree shades (F=17.96; df=57; P<0.001) among the agro-ecological zones (Table 2). In respect of maize plants growing in the open parts of the fields, the mean severity scores recorded for the transition zone (1.458) was not significantly different from that of the forest zone (1.398) but significantly higher (P<0.05) than the coastal savannah zone (1.134).…”

“…It is obligatorily transmitted by as many as six leafhopper species in the genus Cicadulina, (Homoptera: Cicadelidae) in a persistent manner [1] mainly by C. mbila Naudé and C. storey [10,11]. Incidence of MSD has been reported in several African countries including Ghana [9], Nigeria [12], Cameroon [13], Zimbabwe [14], Uganda [15], Kenya [7], Burundi [16] and South Africa (EPPO [17]) and on the islands of adjacent Indian Ocean (Reunion, Mauritius, Madagascar, Sao Tome and Principe) [17][18][19][20][21][22][23].…”