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Understanding consequences of introgression of insecticidal transgenes from Bt-maize into open pollinating maize varieties in South Africa and its impact on pest resistance evolution

Gesuchsteller/in Hilbeck Angelika
Nummer 149072
Förderungsinstrument Südafrika
Forschungseinrichtung Institut für Integrative Biologie Departement Umweltwissenschaften ETHZ
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Forst- und Agrarwissenschaften
Beginn/Ende 01.11.2013 - 30.04.2017
Bewilligter Betrag 229'316.00
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Keywords (5)

pest resistance evolution; small scale farmers; transgenic plants; gene flow; open pollinating varieties

Lay Summary (Deutsch)

Lead
Wir untersuchen die agrar-ökologischen Konsequenzen der Auskreuzung von 'Transgenen', die in gentechnisch veränderten (gv) Hybrid-Maissorten die Produktion eines Insektizids bewirken, in konventionelle, nicht-Hybrid Maissorten, die vorzugsweise von Kleinbauern in Südafrika zur Eigenversorgung oder zum Verkauf auf lokalen Märkten angebaut werden.
Lay summary
Wir untersuchen die agrar-ökologischen Konsequenzen der Auskreuzung von 'Transgenen', die in gentechnisch veränderten (gv) Hybrid-Maissorten die Produktion eines Insektizids bewirken, in konventionelle, nicht-Hybrid Maissorten, die vorzugsweise von Kleinbauern in Südafrika zur Eigenversorgung oder zum Verkauf auf lokalen Märkten angebaut werden. Südafrika ist das einzige Land in Afrika, in dem gv-Mais im agrar-industriellen Stil angebaut wird. Das gv-Insektizid in diesem gv-Mais tötet Stengelbohrer ab. Da es keine reproduktionsbiologischen Barrieren gegen die Auskreuzung von diesen 'Transgenen' auf andere Maispflanzen gibt, sind diese vermutlich schon in nicht-Hybrid Maissorten der Kleinbauern zumindest teilweise eingekreuzt. Aufgrund des hohen Selektionsdrucks im agrarindustriellen Anbau dieses gv-Mais, sind in den letzten Jahren Stengelbohrer in vielen Anbaugebieten resistent geworden gegenüber dem gv-Insektizid. Diese Resistenzentwicklung kam für viele überraschend schnell. Obwohl es eine Reihe von Erklärungsansätzen gibt, ist ein wichtiger Faktor kaum erforscht, nämlich wie sich unkontrolliert ausgekreuzte Transgene in nicht-Hybrid Maissorten auswirken und inwiefern sie zur Förderung der Verbreitung der Resistenzen beitragen können, weil sie den Selektionsdruck auf Stengelbohrer erhöhen können. Daraus soll ein auf Südafrika angepasstes Resistenzentwicklungsmodell entstehen, das eine bessere Resistenz-Risikoanalyse für weitere solche gv-Maissorten ermöglichen soll. Am Ende dieses Projekts werden wir wissen wie sich diese Transgene in nicht-Hybrid Maissorten verhalten, ob und wie sie das gv-Insektizid produzieren und ob sie zur Verbreitung der Resistenz beitragen oder dem Kleinbauern durch seine insektizide Wirkung auch einen Nutzen vermitteln - zumindest zeitweise.
Direktlink auf Lay Summary Letzte Aktualisierung: 19.10.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Genoek Centre for Biosafety Norwegen (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
North-West University, Unit of Environmental Sciences and Management Südafrika (Republik) (Afrika)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
- Forschungsinfrastrukturen
- Austausch von Mitarbeitern
Bioeconomy Chair Prof Wynberg, University of Cape Town Südafrika (Republik) (Afrika)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
XVIII International Plant Protection Congress Vortrag im Rahmen einer Tagung The role of larval behaviour and host plant range in evolution of resistance of the African maize stem borer (Busseola fusca) to Bt maize. 24.08.2015 Berlin, Deutschland van den Berg Johnnie;
International Symposium on the Biosafety of Genetically Modified Organisms (ISBGMO13), Vortrag im Rahmen einer Tagung African maize stem borer resistance to Bt corn in South Africa: implications for IRM in Africa. 09.11.2014 Cape Town, Südafrika (Republik) van den Berg Johnnie;
International Working Group on Ostrinia and other Maize Pests (IWGO) Vortrag im Rahmen einer Tagung Possible explanations for resistance development of the African stem borer (Busseola fusca) to Bt maize and challenges to IRM in Africa. 13.04.2014 Chicago, Vereinigte Staaten von Amerika van den Berg Johnnie;


Veranstaltungen zum Wissenstransfer

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Institute Seminar Series Vortrag 13.11.2014 Zurich, Schweiz


Verbundene Projekte

Nummer Titel Start Förderungsinstrument
171682 PSC Creative Camps for Youth 01.04.2017 Agora

Abstract

The proposed research project addresses the understudied but very important consequences of gene flow and functioning of transgenes from genetically modified hybrid maize into open pollinated maize varieties (OPVs). While transgenic hybrid Bt-maize (for stemborer pest control) is widely used in the industrial agricultural production systems of South Africa (SA) for feed and export, non-transgenic OPVs (mostly maintained through seed-recycling and exchange) remain the prime source of seeds for small scale maize production ensuring the local food security of rural communities which still make up a significant proportion of SA’s society. Although it is known that there are no biological barriers to gene flow among the different maize varieties (hybrids and OPVs) and both ag-systems, industrial and small scale, can exist in close proximity, and, thus, gene flow among these varieties is to be expected to occur regularly, many issues critical for ensuring sustainability of both the GM technology and the small scale farmer’s provisioning of food security remain unstudied. Sustainability of GM Bt-maize varieties in SA hinges critically on the development and spread of resistance in the target pest populations (African stemborer, Busseola fusca). South Africa was among the first countries reporting field-evolved resistance in the target pest of Bt-maize. Today, resistance of target pests has spread far leaving the first single-gene Bt maize varieties (expressing the Bt toxin Cry1Ab) largely ineffective in wide areas of the prime maize producing regions. As a solution, stacked Bt-maize varieties were introduced expressing two Bt toxins one of which is from the same Cry1 class as is expressed in the former single-gene Bt-maize varieties. The issue of flow of Bt-transgenes into OPVs with unknown expression patterns of Bt toxins is of critical importance for the spread and survival of resistant target pests. Non-Bt OPVs did and, possibly, still can serve as refuge for susceptible target pest individuals, however, with unkown prevalence and spread of the Bt-transgenes in OPVs and unknown expression and functionality of these transgenes in such heterogenous genomic backgrounds, this may be increasingly doubtful and is to date entirely speculative. Vice versa, the unknown spread and functionality of Bt-transgenes into OPVs may have consequences for small scales farmers who are entirely unaware of this and the dynamics that introgression of these insecticidal transgenes may entail for them. This research project aims to investigate critical aspects that will determine the sustainability of the new stacked Bt-maize varieties now growing in SA and the efficacy of outcrossed transgenes in OPVs and their utility for small scale farmers. Specific research questions are: (i) how the expression of the acquired transgenes unfolds after introgression into South African (SA) OPVs, (ii) how herbivory (by non-susceptible, non-target pests) influences transgene expression and Bt toxin production in introgressed OPVs (and hybrid Bt-maize for that matter), and (iii) how, vice versa, the (likely variable) transgene introgression and subsequent expression impacts susceptible, target pest survival (bioactivity and efficacy of Bt toxins expressed in introgressed OPVs)? The obtained data we intend to evaluate and assess for compliance with current pest resistance management requirements (high dose/refuge size) and, (iv) to develop an improved pest resistance management model tailored to the specific field situation in South Africa. To answer the above research questions, field trials, greenhouse/climate chamber experiments and bioassays will be complemented with molecular (quantitative real-time PCR) and immunological detection methods (ELISA) applied to both plants and insects. To our knowledge, this has not been done before in such a coordinated and complementary fashion and for African OPV maize production systems. On a more fundamental level, we will gain insight into transgene functioning after introgression into more heterogenous genomic backgrounds like those of open pollinated maize varieties and how this may impact resistance evolution in target pest species, an issue of critical importance in SA.In this project, the two partner groups combine their ideally complementing expertises. The project is aiming to merge two usually separately studied fields - target pest resistance evolution and consequences of gene flow and outcrossing among different maize plant varieties - and generating synergies from both their scientific and methodological competences. The SA partner group is pioneering resistance evolution research in target pests of Bt-maize in southern Africa and bring in the needed field entomological and agronomical expertise for SA maize production systems, both large and small scale. The Swiss group will bring entomological and molecular biology expertise to the project. The Swiss group is pioneering in nontarget insect effects of Bt maize since over a decade and has been contributing significantly to the development of appropriate quantitative ELISA methods and transgene activity measurement in Bt maize. They will further provide first class technical equipment offered through the Genetic Diversity Center/ETHZ and top-of-the-line climate controlled walk-in growth chambers and greenhouses. This laboratory capacity will be complemented by the commercial field capacities of the SA group that does not exist in Switzerland (moratorium on commercial cultivation of GM plants).The outcomes of this project will not only be of great relevance for South Africa but also for other countries with similar mixes of different ag-production systems - industrial commodity production for export/cash and small scale production for local markets and subsistence. Situations where these productions systems may exist side-by-side can be found for example in Brazil and many other South American countries. We have close contacts and previous collaborations with Brazilian research groups that are greatly interested in this research and are engaged in research for which the outcomes of this research project would be of great relevance.
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