In general, the themes of the group are tissue- and development-specific immunmodulation of phytohormone functions and of functions  of  regulatory  and viral proteins in transgenic plants, development of chromatin IP for seeds as well as production of recombinant fiber proteins and  recombinant antibodies in transgenic plants.

The expression of genetically engineered antibodies with high specificity to regulation factors could allow the production of "phenotypic mutants". The phytohormone abscisic acid (ABA) was chosen as a factor to be influenced by antibodies. ABA controls several physiological processes in higher plants; for example closure of stomata, inhibition of precocious germination and stress tolerance. These processes are dependent on ABA concentration as well as on the ABA sensitivity of the tissues involved. In a new approach ABA action was blocked by intracellularly expressed antibodies. Here, the influences of ABA on differentiation of stomata as well on seed development have been studied. Furthermore, the immunomodulation approach has also been used to study the role of jasmonate and OPDA in the stress response. In recent experiments, the role of ABA on induction of transcription factors during salt stress is studied by use immunomodulated Arabidopsis plants. Immunomodulation could also be used to block pathogen functions in different compartments of cells. In a cooperation project with several partners recombinant antibodies against the B and C motif of RNA dependent RNA polymerases of several RNA viruses  have been isolated and stably and transiently expressed in N. benthamiana plants. Resistance against several plant viruses has been shown.

In Arabidopsis thaliana seed-specific transcription factors have key regulatory functions during the development of mature seeds. Here, several high specific and affine recombinant antibodies against transcription factors in seeds have been isolated. The production of these antibodies  and the establishment of chromatin precipitation technology for seeds is under study.

In a further project  the phytoantibody group is dealing with biotechnological problems of antibody expression in plants. Results could be summarised as follows:

• Single chain Fv antibodies (ScFv's) could be accumulated to high concentrations in the endoplasmic reticulum of tobacco leaves, tobacco and pea seeds and potato tubers.
• The functionality was shown by several methods (in vivo effects, specific binding activity, affinity constant).
• ScFv's containing plant material could be stored keeping amount and biological function of the antibodies unchanged.

Recently, fusions of scFv´s with elastin-like peptides (ELP´s) have been shown to further increase the expression of functional recombinant antibodies especially in seeds. In frame of the Pharma-Planta Project production of an neutralizing anti HIV antibody (2F5) as ELP fusions in transgenic plants is studied (see www.pharma-planta.org).

Molecular Farming experiments were further performed with recombinant spider silk proteins to develop production of new materials for technical and medical purposes in plants. This includes field trials and the development of purification strategies.  Several spider silk proteins have been expressed in tobacco and potato. Here, ER retention and fusion to ELP´s have been used as the tools choice for optimised expression. Spider silk – ELP fusion proteins purified from plants have also been successfully used to enhance growth of human cells.