Investigations on the interaction between beet cyst nematode and Arabidopsis thaliana carrying resistance genes from sugar beet
Final Report Abstract
The aim of this study is to determine the interaction between the beet cyst nematode and Arabidopsis thaliana either expressing three recently isolated sugar beet RGAs alone or in combination with the Hsl-pro-l gene. Due to unexpected problems especially during transformation and maintenance of transgenic plants, the major goal of the project has been not reached, so far. The selection of virulent nematodes as described in the grant application has not been crowned by success so far although a number of selection experiments on resistant roots have been initiated. None of the nematodes harvested from resistant roots showed any virulence against Hsl genes in succeeding infection experiments. The collaboration with the plant pathology department, Ames, USA (Prof. T. Baum) has been continued, however, the visit of the PhD student to that institute was postponed because promising A. thaliana families with a substantially reduced cyst number have been selected only recently. The greatest achievement during the funding period was the selection of cZR-7 and cZR-9 transgenic Arabidopsis thaliana T3 lines homozygous for the transgene which showed a significantly reduced reproduction rate of Heterodera schachtii. Moreover, hybrid plants carrying Hsl-pro-l and single RGA sequences have been produced. In addition, we generated new cZR-3 transgenic Arabidopsis plants. Most important, we have generated Hsl-pro-l and cZR-3 double transgenic rapeseed plants. Of these, F2 populations have been produced offering the possibility for an in depth study of interaction between both sequences within a crop species. On the basis of the results presented here we propose the following research activities to be carried out in the future: • Generation of Arabidopsis hybrid plants by crossing of plants carrying single gene constructs as well as by efficient cotransformation experiments. • Comparative cytological and molecular analysis of host pathogen interactions with Arabidopsis single and double transformants • Generation of transgenic B. napus expressing cZR-7 and cZR-9 alone and in combination with Hsl-pro-l • Determination of a possible direct interaction between the different gene products by use of the yeast-two-hybrid system.
