Plants defend themselves against invading pathogens by various mechanisms. The so-called „hypersensitive response“ (HR) is a programmed cell-death which leads to limited breakdown of the plant tissue around the infection site. As a consequence, pathogen spread is restricted.
The tobacco bZIP-transcriptions factor BZI-1 is involved in regulating the plant`s HR (Kuhlmann et al., 2003). By means of a yeast„two-hybrid“-screen, a protein-interaction-partner of BZI-1 has been isolated: the „ankyrin repeat“ protein ANK1.
Plants displaying a reduced ANK1 protein level are strongly affected in growth. Due to enhanced levels of reactive oxygene species (ROS) these plants show symptoms of oxidative stress (more?). ROS are important signaling compounds involved in control of the HR.