No abstract

The 3'-terminal 1221 nucleotides of a Zimbabwe isolate of cowpea aphid-borne mosaic potyvirus (CABMV) genome have been sequenced. The sequence comprises an open reading frame (ORF) of 990 nucleotides and a 3' non-coding-region of 231 nucleotides followed by a poly-A. The ORF has high similarity to NIb and coat proteins (CP) of potyviruses. A potential CP Q/S cleavage site was identified, yielding a CP of 30.5 kDa containing 275 amino acids. The CABMV sequence is closely related to that of South African passiflora virus (SAPV) which should therefore be regarded as a strain of CABMV.

Background Top-soil microbiomes make a vital contribution to the Earth’s ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents. Results The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa’s top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation. Conclusion This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change.

Cowpea ( Vigna unguiculata var. unguiculata ) ((L.) Walp.), a crop native to Africa, is the most important legume grown on the continent, at least in terms of economics. It is a highly nutritious crop, consumed in many forms, including seeds as well as foliage; it provides excellent fodder for livestock as well. Well‐adapted to the semi‐arid tropics, it thrives even on relatively poor soils and low rainfall. Numerous viruses and diseases attack cowpea, but the limiting constraint is insects. Cowpea breeders have had some success in improving cowpea for insect resistance using methods described here, but certain insect pests, including the legume pod borer ( Maruca vitrata ), thrips and pod‐sucking bugs, have proven impervious to conventional breeding to improve resistance. Recently a methodology for genetically transforming cowpea has been developed and is being used to introduce Bt genes into cowpea for resistance against the legume pod borer. The transformation methodology is described, and there is given an overview of biosafety‐related and regulatory matters related to the introduction of Bt cowpea into Africa.

established in 1975, provides evidence-based policy solutions to sustainably end hunger and malnutrition and reduce poverty. The Institute conducts research, communicates results, optimizes partnerships, and builds capacity to ensure sustainable food production, promote healthy food systems, improve markets and trade, transform agriculture, build resilience, and strengthen institutions and governance. Gender is considered in all of the Institute's work. IFPRI collaborates with partners around the world, including development implementers, public institutions, the private sector, and farmers' organizations, to ensure that local, national, regional, and global food policies are based on evidence. Tables, Figures, and Boxes Tables I.1 Regulatory status of genetically engineered crops in the regulatory and development pipeline, 2009 1.1 Estimated area and share of total area planted to transgenic cotton in South Africa, 2000/2001-2007/08 1.2 Summary of findings of main published studies 1.3 Estimated area and share of total area planted to genetically modified maize in South Africa, 2000/2001-2009/10 2.1 Maize and beer consumption and fumonisin exposure (probable daily intake) 2.2 Fumonisin (FB 1) levels in maize and maize products in South Africa 2.3 Possible government interventions and their potential impact 2.4 Percentage of smallholder farmers using purchased seed, by region, 2001 2.5 Comparison of total fumonisin levels in maize in rural KwaZulu-Natal, 2004-2007 (mg/kg = ppb) 2.6 Fumonisin exposure in the Eastern Cape with Bt maize adoption 3.1 Organic cotton production, 1999-2008 3.2 Assumptions for variables and distributions used for partial budget simulations 3.3 Descriptive statistics 3.4 Descriptive statistics of main variables, control of plot 3.5 Cotton profitability for low-and high-input systems, season 2007/08 3.6 Cotton profitability for conventional and organic cotton producers, 2007/08 season 3.7 Partial budgets for scenarios using genetically modified seed 3A.1 All sample (N = 151) 3A.2 Low-input producer (N = 124) 3A.3 High-input producer (N = 27) 3A.4 Conventional producer (N = 139) 3A.5 Organic producer (N = 12) 4.1 Hurdle rates and average annual MISTICs per hectare of genetically modified bananas, per household, and per bananagrowing farm household at different risk-free rates of return and risk-adjusted rates of return 4.2 Comparison of KAP scores with consumer characteristics 4.3 Random-parameter logit model with interactions 4.4 Segment-specific valuation of banana bunch attributes (percentage change in price per banana bunch) 4.5 Compensating surplus and 95 percent confidence intervals for four bunch options a 5.1 GM (genetically modified) crops and products included in the Regional Approach to Biotechnology and Biosafety Policy in Eastern and Southern Africa project 5.2 Immediate export losses if all European importers shunned all "possibly GM" or "possibly GM-tainted" products 6.1 Social costs of biosafety regulations 6.2 Estimates of cost of applications over time (US dollars) and pro...

The helper component-proteinase (HC-Pro) of Cowpea aphid-borne mosaic virus (CABMV) was expressed in Escherichia coli and used to obtain HC-Pro antiserum that was used as an analytical tool for HC-Pro studies. The antiserum was used in immunofluorescence assays to study the subcellular location of HC-Pro expressed with other viral proteins in cowpea protoplasts in a natural CABMV infection, or in protoplasts transfected with a transient expression construct expressing HC-Pro separately from other viral proteins under the control of the 35S promoter. In both cases the protein showed a diffuse cytoplasmic location. Similar localisation patterns were shown in live protoplasts when the transient expression system was used to express HC-Pro as a fusion with the green fluorescent protein as a reporter. In an alternative expression system, the HC-Pro coding region was subcloned in-frame between the movement protein and large coat protein genes of RNA2 of Cowpea mosaic virus (CPMV). Upon transfection of protoplasts with this construct, HC-Pro was expressed as part of the RNA2 encoded polyprotein from which it was fully processed. In this case, the protein localised in broad cytoplasmic patches reminiscent of the typical CPMV induced cytopathic structures in which CPMV replication occurs, suggesting an interaction of HC-Pro with CPMV proteins or host factors in these structures. Finally, recombinant CPMV expressing HC-Pro showed a strongly enhanced virulence on cowpea and Nicotiana benthamiana consistent with the role of HC-Pro as a pathogenicity determinant, a phenomenon now known to be linked to its role as a suppressor of host defense responses based on post-transcriptional gene silencing.

The genomic sequence of a Zimbabwe isolate of Cowpea aphid-borne mosaic virus (CABMV-Z) was determined by sequencing overlapping viral cDNA clones generated by RT-PCR using degenerate and/or specific primers. The sequence is 9465 nucleotides in length excluding the 3' terminal poly (A) tail and contains a single open reading frame (ORF) of 9159 nucleotides encoding a large polyprotein of 3,053 amino acids and predicted Mr of 348. The size of the genome and the encoded polyprotein is in agreement with other potyviruses and contains nine putative proteolytic cleavage sites and motifs conserved in homologous proteins of other potyviruses. The P1 and P3 were the most variable proteins while CI, NIb and CP were the most conserved.

No abstract