At the institute for plant breeding and plant protection of the Martin
Luther University Halle-Wittenberg (professorship for phytopathology and
plant protection) a Ph.D.-position is available. The project is promoted
by the DFG. The candidate should have founded experiences with
molecular-biological techniques. Experience in the handling of
plant-pathogenic fungi would be favourable, but not a prerequisite.
Chitin is a major structural polymer of the cell wall of higher fungi.
Plants, to defend themselves against fungal attack, synthesize
chitinases, often in combination with glucanases. These enzymes are
capable of lysing (disolving) fungal cell walls.
Studying infection structures of taxonomically distinct fungi such as
Uromyces and Colletotrichum, we have observed changes of infection
structure cell wall polymer composition. Upon penetration of host
tissues, chitin is deacetylated and, importantly, the chitosan formed is
not susceptible to plant chitinases. This modification could protect
the pathogen from the plant enzyme defense system. Modifications of
fungal surface polymers are closely correlated with formation and
secretion of chitin deacetylases, enzymes that catalyze deacetylation of
the chitin polymer.
We are trying to investigate the role of fungal cell walls and the
modification of the polymers in the fungal infection process. In this
project we want to apply molecular techniques to investigate the role of
chitin deacetylase genes in successful establishment of the fungus,
Colletotrichum graminicola of its host, Zea mays. The gene(s) should be
cloned either by using heterologous probes or by PCR techniques with
degenerated primers. Northern blots and/or RT-PCR will be used to
determine at which stage of infection structure differentiation the
gene(s) is/are activated. Gene inactivation experiments will be used to
answer the question of whether or not CDA genes are virulence or
I have started to work at the University of Halle, former East Germany,
after accepting the offer of the chair of plant pathology and plant
protection. The building is pretty old, and so are the labs, but
reconstruction in under way. Since molecular genetics has so far not
been applied before in this faculty, new instruments have to be
ordered. For example, the last piece of equipment ordered was be a
capillary DNA sequencer. I expect the lab to be fully functional within
the next six weeks. The project will be a part of a cooperative
approach, in which fungal cell walls are analyzed. Prof. Dr.
Moerschbacher will take the cell wall chemistry part, and Dr. Tenberge,
both from the university at Muenster, will do the electron microscopy.
I also cooperate with Prof. Dr. Mendgen at the university of Constance.
For information contact: Prof. Dr. Deising, Institut für
und Pflanzenschutz, Ludwig-Wucherer-Str. 2, D-06099 Halle (Saale), Tel.:
+49-345-5522660, Fax: +49-345-5527120e-mail: deising at landw.uni-halle.de