Bedeutung von SWEET-Genen für den pflanzlichen Zuckerexport in einer Ektomykorrhizasymbiose

Abstract

In mutualsitic interactions between fungi and plants, such as ectomycorrhiza, the fungus contributes nutrition and obtains plant derived carbohydrates as a response. The carbohydrate transport in ectomycorrhized roots is not yet fully understood and requires additional investigations. However prerequisites for such analysis are transgenic plants. Poplar is a well established model for investigation of ectomycorrhizal symbiosis. As the generation of transgenic poplar plants is a highly time consuming process and can take up to one year a new A. rhizogenes- based transformation protocol was developed in the present thesis. Furthermore, the role of the recently discovered SWEET-proteins in the carbohydrate transport in ectomycorrhiza was investigated. Ectomycorrhiza regulated SWEET proteins were localized in the plasma membrane of Nicotiana benthamiana leaves determining their role in the carbohydrate supply of the fungal partner in ectomycorrhiza. Additionally a promoter analysis of one of the mycorrhiza-induced SWEET genes, PtSWEET 1.c, was performed and two regulatory regions could be identified. However, an ectomycorrhiza specific regulation of the promoter reporter constructs was not observed.