PREP-U Research Project

PREP-U Research Project

In this project, you will design experiments to examine interactions between Arabidopsis thaliana plants (wild-type and mutant) and two different herbivores, the two-spotted spider mite (Tetranychus urticae) and root-knot nematodes (Meloidogyne incognita). The goal of the experiments is to investigate the interaction between the plants and the herbivores to understand the relationships among genes, biochemicals, organisms, and populations. In addition, your work would contribute to a large, multi-national research effort to develop a comprehensive understanding of the biology of flowering plants. Plant science research leads to improvements in food and fuel, as well as discoveries that improve human health and well being.

Why participate?

· Gain research experience,

· Contribute to the scientific understanding of plant-herbivore interactions,

· Learn how Arabidopsis thaliana is used as a model organism,

· Learn about how herbivores and plants interact,

· Learn how to set up a scientific experiment and obtain meaningful results, and

· Earn credit while participating in real research. If you make a novel finding that is included in a publication, you and your work would be acknowledged.

About the Plants

The study of Arabidopsis as a model organism has generated a wealth of information about its genome and the functions of many of its genes. Its appeal to a variety of herbivores allows for investigation into the interactions between plant genes and herbivore behavior (Jander et al, 2001; Mitchell-Olds, 2001; van Poecke et al., 2003). The characteristics that make it a good model for research include: a short life cycle (6-8 weeks), abundant progeny (thousands of seeds per plant), and small size (plants rarely grow more than 12 inches tall and 8-10 plants can grow in a 3x3 inch pot).

The research project will involve the study of Arabidopsis plants with an altered [need to determine which gene has been altered and provide information about why this gene may influence the plant’s interaction with herbivores]. Results of this work can offer insight into the involvement of [XYZ gene / XYZ pathway] in plant-herbivore interactions, for example:

1. Do wild-type and mutant plants differ in their acceptability to the herbivores as food?

2. Do herbivore characteristics differ in response to feeding on wild-type versus mutant plants?

3. Do plant responses to herbivory differ between wild-type and mutant plants?

About the Herbivores

The two-spotted spider mite, Tetranychus urticae, is a leaf-feeding herbivore and a serious agricultural pest known for rapid population growth and extreme polyphagy (i.e., they will eat a lot of many different food sources; Jeppson et al., 1975; Sabelis, 1981). Root-knot nematodes, Meloidogyne incognita (and other Meloidogyne species), are root-infecting plant-parasitic nematodes that represent the most devastating of the soil-borne nematode pests of plants (Sassner and Carter, 1985). These herbivores were chosen not only because of their impact on agriculture, but also because they will feed on Arabidopsis (van Poecke et al, 2003; Huang et al., 2002; E. Lewis, unpublished data).

About the Project

Working in groups of four, you will be able to choose from different Arabidopsis mutants, herbivores, and experimental and analytical tools to design and conduct your own experiments. If you get involved, you will (timeline is approximate):

· Attend an introductory session in class to learn more about the plants, herbivores, and experimental tools,

· Write a brief (one to two paragraph) proposal outlining which question / hypothesis you plan to address, how you plan to address it (experimental design), what materials you will need, and what data you anticipate collecting,

· Meet with the research project instructor(s) to discuss and fine-tune your proposal and set up your experiment,

· Collect data (work can be split across group members) for 5-6 weeks as the plants grow,

· Analyze your data, draw conclusions, and develop recommendations for future research, and

· Report about your work using a Powerpoint presentation or final report.

References

Huang X, PS Springer, I Kaloshian. 2002. Expression of the Arabidopsis MCM Gene PROLIFERA during root-knot and cyst nematode infection. Phytopathology 93: 35-41.

Jander G, J Cui, B Nhan, NE Pierce, FM Ausubel. 2001. The TASTY locus on chromosome 1 of Arabidopsis affects feeding of the insect herbivore Trichoplusia ni. Plant Physiol 126: 890-898.

Jeppson LR, HH Keifer, EW Baker. 1975. Mites injurious to economic plants. University of California Press, Berkeley, California, USA.

Mitchell-Olds, T. 2001. Arabidopsis thaliana and its wild relatives: a model system for ecology and evolution. Trends Ecol Evol 16: 693-700.

Pelletier MK, JR Murrell, BW Shirley. 1997. Characterization of Flavonol Synthase and Leucoanthocyanidin Dioxygenase Genes in Arabidopsis. Plant Physiol 113: 1437-1445.

Sabelis MW. 1981. Biological control of two-spotted spider mites using phytoseiid predators. Part 1. Modeling the predator-prey interaction at the individual level. Agricultural Research Reports No. 910. Wageningen.

Sasser JN, CC Carter. 1985. An advanced treatise on Meloidogyne, Volumes I and II. North Carolina Sate University Graphics: Raleigh, NC.

Van Poecke RMP, M Roosjen, L Pumarino, M Dicke. 2003. Attraction of the specialist parasitoid Cotesia rubecula to Arabidopsis thaliana infected by host or non-host herbivore species. Entomologica Experimentalis et Applicata 107: 229-236.