Potatoes, pathogens and pests : effects of genetic modifi cation for plant resistance on non-target arthropods

Currently, fungicides are necessary to protect potato crops against late blight, Phytophthora infestans, one of the world’s most damaging crop pathogens. The introgression of plant resistance genes from wild potato species targeted specifically to the late blight pathogen into susceptible potato varieties may alleviate the environmental impact of chemical control. Genetically modified plants are subject to an environmental risk assessment, and this includes testing for risks to the non-target arthropod community associated with the crop. The thesis begins with a review about the main plant defense responses and their role in influencing sequential interactions between herbivores and plant pathogens. The experimental chapters each focus on different aspects of the interaction between potato plants (both resistant and susceptible), the target pathogen (P. infestans) and several non-target insects. With each chapter, the scope widens: from the molecular gene expression in potato leaves in response to sequential attacks, to field scale biodiversity analyses. At the molecular level, one of the main findings was that the genomic position of the Rpi-vnt1 insertion conferring resistance to P. infestans influenced potato gene expression measured in leaves, when interacting with the non-target insect pests Myzus persicae (Green peach aphid) and Leptinotarsa decemlineata (Colorado potato beetle). Insect performance differed between the resistant GM and susceptible non-GM comparator. In the following chapter, the differences in insect performance were tested across a range of conventionally bred cultivars varying in resistance to P. infestans. Differences in M. persicae performance between several cultivars greatly outweighed the differences previously detected between the GM and non-GM comparator. These results are crucial in shaping the way risk is assessed in the context of GM crops, and these results are supported in our experiments assessing effects on biodiversity with pitfall traps in the field. The third trophic level was also addressed by comparing the performance of the parasitoid Aphidius colemani reared on GM and non-GM fed aphids, both with an without exposure to P. infestans. Differences in parasitoid performance were only found on the susceptible cultivar when inoculated with P. infestans. In the last experimental chapter the risk assessment is taken to the field comparing pitfall trap catches over two years and in two countries. Different methods for statistical analysis of biodiversity data were compared to arrive at recommendations for such analysis in the framework of environmental risk assessments. Drawing on these lessons, the discussion ends with ideas for the development of protocols for environmental risk assessments in the light of expected scientific progress in agricultural biotechnology

Feiten en cijfers vergroening GLB 2019

Voorliggend rapport presenteert de uitkomsten van een monitoring van de vergroening voor het jaar 2019 volgens de geactualiseerde methode en gebruikmakend van gegevens die werden verzameld in samenwerking met RVO. De evaluatie laat zien hoe en door welke boeren maatregelen voor blijvend grasland, gewasdiversificatie en ecologische aandachtsgebieden en tevens de equivalente maatregelen zijn opgepakt. De resultaten werden geïnterpreteerd wat betreft te verwachten effecten in relatie tot de gestelde doelen van de vergroening. In de analyse worden ook de resultaten uit de voorgaande monitoringsrapportage betrokken, zodat een beeld ontstaat van de vergroening na vijf jaar

The state of cactus fences and kunukus for nature inclusivity on the island of Bonaire

Agriculture on Bonaire does not support the demand for food on the island, and therefore the people are dependent on expensive food importation. Recently, any Bonairean people abandon their kunukus to take jobs in the urban area in tourism or off-island in the oil industry. Traditionally, a kunuku was used as an agricultural plot for food production for the household. A kunuku would usually have a cactus fence used to contain grazing goats or chickens, or to produce household amounts of sorghum maize, and keep animals out. In order to help restore nature to Bonaire and include it in the daily lives of people, restoration and use of cactus fences on kunukus are being considered as nature inclusive measure. In order to get a better understanding of the current use of kunukus and presence of cactus fences on the island, satellite information and field observations were collected about the state of kunukus and the use of cactus fences. Results show that kunukus are rapidly being abandoned. The predictive accuracy from satellite imagery of active kunukus was high (92.5%). Furthermore, only 4% of the active kunukus have a well-maintained cactus fence. Implications of these findings are discussed with focus on nature inclusiveness and the use of the kunuku as a means to restore a cultural pride, self-sufficiency, local economic diversification and a healthier food culture on Bonaire

Inoculation of susceptible and resistant potato plants with the late blight pathogen Phytophthora infestans : effects on an aphid and its parasitoid

Plants are exposed to microbial pathogens as well as herbivorous insects and their natural enemies. Here, we examined the effects of inoculation of potato plants, Solanum tuberosum L. (Solanaceae), with the late blight pathogen Phytophthora infestans (Mont.) de Bary (Peronosporales: Pythiaceae) on an aphid species commonly infesting potato crops and one of the aphid's major parasitoids. We observed the peach-potato aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), and its natural enemy, the biocontrol agent Aphidius colemani Viereck (Hymenoptera: Braconidae), on potato either inoculated with water or P. infestans. Population growth of the aphid, parasitism rate of its natural enemy, and other insect life-history traits were compared on several potato genotypes, the susceptible cultivar Désirée and genetically modified (GM) isogenic lines carrying genes conferring resistance to P. infestans. Effects of P. infestans inoculation on the intrinsic rate of aphid population increase and the performance of the parasitoid were only found on the susceptible cultivar. Insect traits were similar when comparing inoculated with non-inoculated resistant GM genotypes. We also tested how GM-plant characteristics such as location of gene insertion and number of R genes could influence non-target insects by comparing insect performance among GM events. Different transformation events leading to different positions of R-gene insertion in the genome influenced aphids either with or without P. infestans infection, whereas effects of position of R-gene insertion on the parasitoid A. colemani were evident only in the presence of inoculation with P. infestans. We conclude that it is important to study different transformation events before continuing with further stages of risk assessment of this GM crop. This provides important information on the effects of plant resistance to a phytopathogen on non-target insects at various trophic levels.</p

Inoculation of susceptible and resistant potato plants with the late blight pathogen Phytophthora infestans : effects on an aphid and its parasitoid

Plants are exposed to microbial pathogens as well as herbivorous insects and their natural enemies. Here, we examined the effects of inoculation of potato plants, Solanum tuberosum L. (Solanaceae), with the late blight pathogen Phytophthora infestans (Mont.) de Bary (Peronosporales: Pythiaceae) on an aphid species commonly infesting potato crops and one of the aphid's major parasitoids. We observed the peach-potato aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), and its natural enemy, the biocontrol agent Aphidius colemani Viereck (Hymenoptera: Braconidae), on potato either inoculated with water or P. infestans. Population growth of the aphid, parasitism rate of its natural enemy, and other insect life-history traits were compared on several potato genotypes, the susceptible cultivar Désirée and genetically modified (GM) isogenic lines carrying genes conferring resistance to P. infestans. Effects of P. infestans inoculation on the intrinsic rate of aphid population increase and the performance of the parasitoid were only found on the susceptible cultivar. Insect traits were similar when comparing inoculated with non-inoculated resistant GM genotypes. We also tested how GM-plant characteristics such as location of gene insertion and number of R genes could influence non-target insects by comparing insect performance among GM events. Different transformation events leading to different positions of R-gene insertion in the genome influenced aphids either with or without P. infestans infection, whereas effects of position of R-gene insertion on the parasitoid A. colemani were evident only in the presence of inoculation with P. infestans. We conclude that it is important to study different transformation events before continuing with further stages of risk assessment of this GM crop. This provides important information on the effects of plant resistance to a phytopathogen on non-target insects at various trophic levels.</p

Biodiversity analyses for risk assessment of genetically modified potato

An environmental risk assessment for the introduction of genetically modified crops includes assessing the consequences for biodiversity. In this study arthropod biodiversity was measured using pitfall traps in potato agro-ecosystems in Ireland and The Netherlands over two years. We tested the impact of site, year, potato genotype, and fungicide management regime on arthropod community composition. Three potato genotypes were compared: the cultivar Désirée, susceptible to the late blight pathogen Phytophthora infestans, a genetically modified cisgenic clone of Désirée resistant to P. infestans and the cultivar Sarpo Mira, also resistant to late blight. We aimed to test several ways to measure biodiversity in the context of risk assessment by using both univariate biodiversity indices and multivariate ordination methods, categorizing the pitfall trap catch by taxonomic or functional category. The Shannon-Wiener and Simpson biodiversity indices both showed strong differences between sites, years and potato genotypes, but showed no effects of the fungicide management regime. The effect of genotype was due to cultivar differences between Désirée and Sarpo Mira rather than between the GM-event (A15-31) and its isogenic comparator Désirée. Multivariate permutation analyses and RDA ordination confirmed these findings and also showed interactions between year, site and either genotype or treatment. The added value of the multivariate analysis was that it provided information on the specific arthropod groups or taxa that contributed to community structure. Multivariate analyses are recommended for use as a sensitive method to compare functionally important arthropod groups driving community structure within the framework of environmental risk assessments, or for the process of indicator species selection

Biodiversity analyses for risk assessment of genetically modified potato

An environmental risk assessment for the introduction of genetically modified crops includes assessing the consequences for biodiversity. In this study arthropod biodiversity was measured using pitfall traps in potato agro-ecosystems in Ireland and The Netherlands over two years. We tested the impact of site, year, potato genotype, and fungicide management regime on arthropod community composition. Three potato genotypes were compared: the cultivar Désirée, susceptible to the late blight pathogen Phytophthora infestans, a genetically modified cisgenic clone of Désirée resistant to P. infestans and the cultivar Sarpo Mira, also resistant to late blight. We aimed to test several ways to measure biodiversity in the context of risk assessment by using both univariate biodiversity indices and multivariate ordination methods, categorizing the pitfall trap catch by taxonomic or functional category. The Shannon-Wiener and Simpson biodiversity indices both showed strong differences between sites, years and potato genotypes, but showed no effects of the fungicide management regime. The effect of genotype was due to cultivar differences between Désirée and Sarpo Mira rather than between the GM-event (A15-31) and its isogenic comparator Désirée. Multivariate permutation analyses and RDA ordination confirmed these findings and also showed interactions between year, site and either genotype or treatment. The added value of the multivariate analysis was that it provided information on the specific arthropod groups or taxa that contributed to community structure. Multivariate analyses are recommended for use as a sensitive method to compare functionally important arthropod groups driving community structure within the framework of environmental risk assessments, or for the process of indicator species selection

Bonaire 2050 : Putting the vision into numbers

Bonaire is facing major challenges including (mass) tourism, population growth, urban expansion, climate change, biodiversity loss and the unilateral dependency on tourism. In thirty years, Bonaire will inevitably look different. Here, two different possible futures are presented, to form a basis for dialogue amongst stakeholders and to stimulate a positive change and sustainability on Bonaire. One of these scenarios follows current trends (business-as-usual), and the other bends those trends into a nature-inclusive future after a vision developed by a trans-disciplinary team of researchers, local experts and stakeholders. For both scenarios drivers and impacts are visualized and documented on climate, tourist numbers, population,infrastructure, resources, land use, erosion and nature. Visualizing scenarios is one important piece in creating awareness about the future as it allows to shed light of the difficult to grasp long-term effects, and explicitly showcases current trends. It gives opportunities to imagine a future that looks different from the prognosis, and to inspire to work towards a sustainable and desirable future