A Framework for Effective Bt Maize IRM Programs: Incorporation of Lessons Learned From Busseola fusca Resistance Development

Best practices for acceptability of GM crops field trials conclusions: lessons for Africa

The ability to transfer information about the performance, safety, and environmental impacts of a genetically modified (GM) crop from confined field trials (CFTs) conducted in one location to another is increasingly gaining importance in biosafety regulatory assessment and decision-making. The CFT process can be expensive, time-consuming, and logistically challenging. Data transportability can help overcome these challenges by allowing the use of data obtained from CFTs conducted in one country to inform regulatory decision-making in another country. Applicability of transported CFT data would be particularly beneficial to the public sector product developers and small enterprises that develop innovative GM events but cannot afford to replicate redundant CFTs, as well as regulatory authorities seeking to improve the deployment of limited resources. This review investigates case studies where transported CFT data have successfully been applied in biosafety assessment and decision-making, with an outlook of how African countries could benefit from a similar approach.

Screening for resistance alleles to Cry1 proteins through targeted sequencing in the native and invasive range of Spodoptera frugiperda (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a highly polyphagous pest native to the tropical Americas that has recently spread to become a global super-pest threatening food and fiber production. Transgenic crops producing insecticidal Cry and Vip3Aa proteins from Bacillus thuringiensis (Bt) are used for control of this pest in its native range. The evolution of practical resistance represents the greatest threat to sustainability of this technology and its potential efficacy in the S. frugiperda invasive range. Monitoring for resistance is vital to management approaches delaying S. frugiperda resistance to Bt crops. DNA-based resistance screening provides higher sensitivity and cost-effectiveness than currently used bioassay-based monitoring. So far, practical S. frugiperda resistance to Bt corn-producing Cry1F has been genetically linked to mutations in the SfABCC2 gene, providing a model to develop and test monitoring tools. In this study, we performed targeted SfABCC2 sequencing followed by Sanger sequencing to confirm the detection of known and candidate resistance alleles to Cry1F corn in field-collected S. frugiperda from continental USA, Puerto Rico, Africa (Ghana, Togo, and South Africa), and Southeast Asia (Myanmar). Results confirm that the distribution of a previously characterized resistance allele (SfABCC2mut) is limited to Puerto Rico and identify 2 new candidate SfABCC2 alleles for resistance to Cry1F, one of them potentially spreading along the S. frugiperda migratory route in North America. No candidate resistance alleles were found in samples from the invasive S. frugiperda range. These results provide support for the potential use of targeted sequencing in Bt resistance monitoring programs.

Recent Research on Fusarium Mycotoxins in Maize—A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Managing Fall Armyworm in Africa: Can Bt Maize Sustainably Improve Control?

The recent invasion of Africa by fall armyworm, Spodoptera frugiperda, a lepidopteran pest of maize and other crops, has heightened concerns about food security for millions of smallholder farmers. Maize genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) is a potentially useful tool for controlling fall armyworm and other lepidopteran pests of maize in Africa. In the Americas, however, fall armyworm rapidly evolved practical resistance to maize producing one Bt toxin (Cry1Ab or Cry1Fa). Also, aside from South Africa, Bt maize has not been approved for cultivation in Africa, where stakeholders in each nation will make decisions about its deployment. In the context of Africa, we address maize production and use; fall armyworm distribution, host range, and impact; fall armyworm control tactics other than Bt maize; and strategies to make Bt maize more sustainable and accessible to smallholders. We recommend mandated refuges of non-Bt maize or other non-Bt host plants of at least 50% of total maize hectares for single-toxin Bt maize and 20% for Bt maize producing two or more distinct toxins that are each highly effective against fall armyworm. The smallholder practices of planting more than one maize cultivar and intercropping maize with other fall armyworm host plants could facilitate compliance. We also propose creating and providing smallholder farmers access to Bt maize that produces four distinct Bt toxins encoded by linked genes in a single transgene cassette. Using this novel Bt maize as one component of integrated pest management could sustainably improve control of lepidopteran pests including fall armyworm.