Research themes - Plant Ecology and Phytochemistry
Project 1:
Evolutionary Ecology and Plant Reproduction
One of the main targets is to explain the evolution of dioecy. Alternative hypotheses relate to sexual selection favouring one single sex and inbreeding depression due to self-fertilisation in hermaphrodites. Experimental studies are supported by theoretical studies in collaboration with the section Theoretical Biology. Supporting studies relate to genetic variation in attraction of pollinators by individual plants through nectar production and experiments on selective embryo abortion.Project 2:
Ecology and Evolution of Herbivory and Plant Defences
Plants are subject to herbivory and diseases. Two distinct mechanisms have evolved that reduce fitness loss due to these attacking powers: defence and tolerance. Defence reduces the level of herbivory, tolerance reduces the effects of herbivory. We study the genetic control of defence and tolerance, the physiological, biochemical and ecological mechanisms and the population dynamical consequences.Project 3:
Microbial Ecology
Micro organisms play vital roles in all ecosystems on earth. In terrestrial ecosystems the interaction of bacteria and fungi with plants is of primary importance for the growth of plants and therefore for the functioning of the ecosystem. There is a strong feedback between soil micro-organisms and plants. Plants provide substrate for growth and maintenance of microbial populations and micro-organisms have a strong impact on plants, what can be either positive or negative. For instance, microbial soil-borne pathogens hamper the growth of plants whereas microbial symbionts stimulate nutrient uptake and microbial antagonists suppress the activity of the pathogens.
The close interaction between plants and micro-organisms is most intense in the immediate surroundings of the roots, the so-called rhizopshere. Research within this project is mainly directed towards the influence of plants on the structure and activity of microbial communities in the rhizosphere, and in particular on the interaction of plant pathogens and their antagonists.Project 4
Applied Ecology of Herbivore Resistance
The rich chemical diversity of plants is the result of ongoing evolutionary processes. Enzymes of natural product biosynthesis arise through mutation and gene duplication leading to the continued elaboration of new chemical structures that will be selected for if they impart an adaptive advantage on the plant. Plant natural products can have positive impacts on human health, providing scope for molecular approaches to crop improvement based upon the manipulation of natural product profiles. We identify compounds related to thrips (Frankliniella occidentalis) resistance in co-operation with Plant Metabolomics. We couple thrips bioassays with Nuclear Magnetic Resonance Spectroscopy (NMR). Projects comprise thrips resistance in tomatoes (ERA-NET Plant Genomics project TRITOP), chrysanthemums (in co-operation with the Dutch chrysanthemum breeders), Arabidopsis (in co-operation with Genetwister Technologies) and the wild plant genus Senecio. A future project for thrips resistant cucumber is planned in co-operation with Enza Zaden. We also test plants commercially for resistance against thrips and leaf miners. The many bioassays we did with chrysanthemum have shown to be exact and repeatable and can be done at a competitive price. Dr. Kirsten Leiss is co-ordinator of the applied herbivore resistance research.Project 5
Ecological risk assessment of Genetically Modified plants
The public debate about ecological risks of importing or growing GM plants has not silenced yet and there are different views on this in both the Netherlands and in the European Union. We study GM plants to quantify the probability by which certain events occur and the effects on the ecosystem if the events occur. Projects include the cultivated carrot (possible introgression with the wild carrot), effect of GM potatoes on non-target organisms and weediness in oilseed rape (see also under grants). We cooperate with Theoretical biology (Dr. Patsy Haccou), the CML (Prof. Geert de Snoo and Dr. Wil Tamis), Evolutionary Biology (Prof. Paul Brakefield), the University of Amsterdam (Prof. Peter van Tienderen), the NIOO (Prof. Hans van Veen, Dr. Nicole van Dam) and FLORON (Drs. Kees Groen). In a project sponsored by the COGEM we explore ways to monitor Brassica rapa/ B. napus populations in the Netherlands. Dr. Tom de Jong coordinates the work on GM plants in Plant Ecology, he is also a member of the Dutch COGEM (www.cogem.net).Project 6:
Plant – pollinator interaction networks
Understanding interaction patterns between flowers and pollinators at the level of whole communities is important for biodiversity conservation because species form a complex web of interactions. A change in species composition due to climate change, invasive species and species loss might change the interaction patterns of the plants and animals and thus the stability of the whole community. In this project we study the influence of species trait (such as abundance, nectar depth, proboscis length, nectar production rate, body size and handling time) on visitation frequency of pollinators to flowers in a community context. By using probabilistic models that include size thresholds, size - number trade-offs, allometric scaling laws and optimal foraging rules we analyze the relative impact of these species traits on the structure and stability of the interaction network.
Recent grants
Chain of transport of GM seeds. Project leader Tom J. de Jong. The project is funded by the COGEM, the Dutch advisory committee on genetically modified organisms. The research occurs in close cooperation with Dr. Wil Tamis of the CML. A final report will be ready in January 2009.Monitoring of oilseed rape populations. Project leader Tom J. de Jong. The project is funded by the COGEM, the Dutch advisory committee on genetically modified organisms. The research is carried out by post-doc Sheila Luijten and occurs in cooperation with Wil Tamis of the CML and Kees Groen of FLORON. A final report will be available in December 2009.
ERA-PG (2007-2011) TRITOP thrips resistance in tomato plants. Project leader Dr. P.G.L. Klinkhamer, in cooperation with Prof. R. Verpoorte (Plant Metabolomics), Prof. C. Martin (John Innes Centre, Norwich, UK) and Dr. A. Fernie (Max Planck Institute, Golm, Germany). Dr. Kirsten Leiss has a post-doc position in this project. The project aims at developing tomato lines resistant to Western Flower Thrips by increasing CGA levels by way of genetic engineering. The project will 1) explore the natural variation in CGA levels in tomato, 2) identify the genetics behind CGA production levels, 3) understand the relationship of CGA biosynthesis to other primary and secondary metabolite pathways, 4)increase the understanding of the role of CGA in thrips resistance 5) identify possible synergy of CGA with other compounds and determine the activity of various other cinnamic acid esters against thrips.
Senter Novem Innovation voucher from the Genetwister Technologies B.V. Thrips bioassays in Arabidopsis. Project leader is Dr. P.G.L. Klinkhamer. The research is carried out by the post-doc Kirsten Leiss. Such innovation vouchers from Genetwister Technologies are carried out on a regular basis.
We have several recent ERGO projects. In Dutch ERGO means “Ecologie Rond Genetisch gemodificeerde Organismen” Our group participates in several projects. See: http://www.nwo.nl/nwohome.nsf/pages/NWOA_6JNP94ERGO 1 “Quantifying introgression risks of transgenes with hazard rates, using carrot as a model species”. Projectleader Dr. Patsy Haccou. Dr. Jun Rong works as a Postdoc in this project in Plant Ecology and Drs Cilia Grebenstein has a PhD position,which is partly supervised by plant ecology. The project aims at measuring hazard rates of introgression of transgenes from cultivated carrot to its wild relatives. A theoretical model to estimate hazard rates will be developed (subproject 1, Theoretical Biology, Dr. P. Haccou ) that will be fed with data obtained from selection experiments in lab and field and historical data (subproject 2, CML, Prof. G. de Snoo and Dr. W. Tamis, Plant Ecology, Dr T. de Jong) and measurements of gene flow between crops and wild relatives and the spread of cultivar genes into more distant wild populations (subproject 3, Plant Ecology, Dr. K.Vrieling).
ERGO 2 “Developing baselines and protocols for evaluating the direct and indirect effects of GMP’s on the above-ground insect community using GM potatoes as a case study.” Projectleader Peter Klinkhamer. This project is in cooperation with Prof. P. Brakefield (Evolutionary Biology) and involves two postdoc’s Maaike Bruinsma and Andreas Plischke and a technician that start in fall of 2008 with studying the effects of GM potato on target and non-target organisms.
ERGO 3 “A decision-support system for plant traits constituting ecological risks: Frankenstein food meets weeds from hell”. Model species are B. napus (Oilseed rape) and Agrostis stolonifera (Creeping bentgrass). The project is in cooperation with Wil Tamis of the CML and with Prof. P. van Tienderen (University of Amsterdam) who was awarded a complementary project about effects of GM plants on ecosystem processes. At present we have two vacancies for a three-year-period, for a post-doc and for a technician. We hope to have these vacancies filled and start the project in January 2009.
