Carlos Sanchez Arcos

   Department of Biochemistry
   Plant-Aphid Interactions
 Phone:+49 (0)3641 57 1339Max Planck Institute for Chemical Ecology
 Fax:+49 (0)3641 57 1302Hans-Knöll-Straße 8
  emailD-07745 Jena

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PhD Thesis

started in Feb 2012
Legume chemistry and the specificity of pea aphid host races
Friedrich-Schiller-University Jena, Biologisch-Pharmazeutische Fakultät
First Supervisor: Prof. Dr. J. Gershenzon
Co-Supervisor(s): Dr. G. Kunert, Prof. Dr. G. Pohnert (Institute of Inorganic and Analytical Chemistry, FSU)

Although most of the insect herbivores under study in our institute feed by chewing on plant material, herbivores that suck plant fluids, such as aphids, whiteflies, thrips and leafhoppers, are a prominent group that causes enormous damage to natural and cultivated plants worldwide. We are investigating the pea aphid (Acyrthosiphon pisum), a model sucking herbivore whose genome has been fully sequenced, to understand the causes of feeding specialization on different host plants. Collectively, pea aphids feed on a range of host plants in the Legume family (Fabaceae), but host races exist that exhibit a clear preference for specific plants such alfalfa (Medicago sativa), red clover (Trifolium pratense), pea (Pisum sativum), upon which they perform better. This ecological specialization can be considered a first step towards sympatric speciation since the host fidelity of races leads to assortative mating which reduces gene flow among host races.

The specialization of pea aphids is thought to arise principally from their diet. Although phloem generally contains a high concentrations of sugars and free amino acids, as well as some macromolecules such as proteins or RNAs, a large range of secondary metabolites accumulate whose content varies with the plant species. Some legume secondary metabolites, for example saponins in alfalfa, and alkaloids in white lupine (Lupinus albus L.) have a strong influence on pea aphid performance. However, the role of host plant chemistry for the specificity of pea aphid host races has not been studied.

The aim of this project is the identification of chemical compounds in the phloem sap of alfalfa (Medicago sativa), red clover (Trifolium pratense), pea (Pisum sativum) and broad bean (Vicia Faba) involved in determining the pattern and the maintenance of host plant usage by pea aphid host races.
last updated on 2014-02-10