Pablo Chong Aguirre graduates at Wageningen University and Research

On Monday 31 October 2016 Pablo Chong Aguirre, originating from Ecuador, successfully defended his PhD thesis on “The origin, versatility and distribution of azole fungicide resistance in the banana black Sigatoka pathogen Pseudocercospora fijiensis”. Professors Pedro Crous and Gert Kema, Pablo’s supervisors, proudly presented the diploma to Pablo. The research papers from Pablo’s thesis are foreseen for 2017.

Read about the PhD thesis that Pablo Chong Aguirre defended here:


Pseudocercospora fijiensis causes black Sigatoka disease of banana. It is one of the most damaging threats of the crop requiring excessive fungicide applications for disease control as the major export “Cavendish” clones are highly susceptible. The consequence of this practice is the reduced efficacy of disease management strategies due to increasing levels of fungicide resistance. In this thesis the history and current practices of black Sigatoka disease management as well as the underlying mechanisms of fungicide resistance to a major group of fungicides are described. We discovered that both target site mutations and promotor insertions are crucial for modulating sensitivity. The more insertions, the higher the expression of the gene and the more resistant the strain. Using this information, we advocate modern monitoring techniques and improved disease control strategies as well as the urgent need for innovative banana breeding to develop resistant varieties for a sustainable global banana production.

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Securing the future of the UK’s favourite fruit

The British Biotechnology and Biological Sciences Research Council (BBSRC) granted a project to the University of Exeter on “Securing the future of the UK’s favourite fruit”. The UK is highly dependent on imported fruit and vegetables that make up eighty per cent of the market, compared with half of cereals and one sixth of meat and dairy produce. Yet, fruit and vegetables are a key component of a healthy diet, often overlooked in studies of global food security that tend to focus on the major grains. Reliance on imports makes the UK vulnerable to instabilities in international production and supply, placing the issue of resilience of the UK food system firmly in a global context. This vulnerability is epitomized by the banana, the most popular fruit in the UK by consumption, and the most important fruit in the world by production. More than five billion bananas are purchased in Britain each year, and the UK accounts for seven per cent of the global export market. Though hundreds of banana varieties are grown around the world for domestic consumption, only one variety, Cavendish, is internationally traded. The previous export variety, Gros Michel, was eliminated by Panama Disease (Fusarium oxysporum f. sp. cubense) in the 1950s, and now a new virulent strain, Tropical Race 4 (TR4), is emerging from Asia to threaten Cavendish. No alternative tradable varieties are available, and no chemical disease controls exist. The vulnerability of the banana trade is an extreme case of the more general issue of imported crops that are vulnerable to emerging pests and diseases.

However, the banana remains under-researched compared with the major crops, there has been little academic analysis of the resilie

nce of the banana trade nor development of mitigation strategies to maintain supply or manage the impact of sudden catastrophe. In this multidisciplinary research programme, the UN FAO World Banana Forum (WBF) will collate detailed data on production levels, disease impacts, and mitigation methods. In this project patterns, trends and drivers of banana production, including pests, diseases, management, and climate, will be analyzed to provide robust models of production and how this could vary in the future as diseases spread and the climate changes. Wageningen University and Research will test a new antifungal compound against TR4, to determine whether chemical control could mitigate production impacts while alternative resistant varieties remain under development.

In addition, an economic model will be developed that characterizes the main features of the UK value chain, forming the basis for assessing the price transmission impacts following shocks in upstream markets and, by extension, the impact on UK consumers and the responses by UK food retailers and other market intermediaries. The theoretical framework will be calibrated and simulates the impact of projected production shocks in exporting countries on UK consumers, and derives the welfare impact for participants at each stage of the value chain.

The banana market is politically sensitive, and over the past decade the price of bananas in the UK has declined, while production costs have increased, placing pressure on producers. Via the WBF, the UK charity Banana Link and the food sector consultancy 3Keel the UK retail sector will be engaged along with other stakeholders in rigorous key informant analysis of potential responses to vulnerabilities in the sector, impacts of prices rises on the UK consumer, feedbacks to producers, and strategies to improve resilience to production shocks. The projects’ goal is to secure the future of the UK’s favourite fruit, and provide a case study for improving the resilience of other vulnerable imported commodities.

See also: the BBSRC flyer about this research

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Since October 2014 a new PhD student from Indonesia, Fajarudin Ahmad, started at Wageningen University & Research centre to study the genes responsible for resistance to Panama disease.

The program deals with segregating banana populations and state of the art cytogenetics techniques. Last October, Fajarudin started his research with crossing two wild diploid banana accessions with different levels of resistant to the Tropical Race 4 strain of Fusarium oxysporum f.sp. cubense (TR4), the causal agent of Panama disease in Cavendish bananas and a range of additional banana germplasm. He created progenies by pollinating the banana flowers by hand and by selfing. In the next months he will use these populations for studying segregation and eventually for genetic mapping of TR4 resistance.

Fajarudin is now propagating the progenies by tissue culture in order to have sufficient plants for statistically sound phenotyping. During this process he devotes his time to preliminary microscopical meiosis observations of pollen mother cells in the parents using DAPI staining enabling him to observe chromosome pairing disturbances.

In the coming years Fajarudin will focus on studying the inheritance of TR4 resistance in banana. Fajarudin: “After four years I hope to have found the genes, which are responsible to TR4 resistance in Indonesian wild germplasm that will support breeding initiatives aiming at delivering resistant bananas to the market”.

The research of Fajarudin is funded by the KNAW-SPIN project.

Click here to send an email to Gert Kema for more information about Fajarudin’s project.

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For the coming five years, Stichting Dioraphte is making available over 1.7 million Euros for the banana research of Wageningen UR. Part of this will be used for a research project which will start soon. The larger part of the sum will be used to fund a depth study within the current banana research.

Stichting Dioraphte has previously been involved in the banana research led by Gert Kema, a banana expert at Wageningen UR. At the start of the research for the fungal disease Black Sigatoka in the period 2007-2009, Stichting Dioraphte provided a financial boost for the Wageningen UR research. Stichting Dioraphte is very impressed by the current extent of the programme, and therefore decided to greatly support the banana research over the next five years with a new donation.

Deepening the research into Panama Disease
A large part of the donation will be used to deepen the current research into Panama Disease in bananas. Kema: ‘With this financing, it will be possible to expand the team and establish strategic research lines.’

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