Redox-regulation of the NPR1/TGA1 system

The role of redox-active molecules, such as reactive oxygen and nitrogen species in local and systemic defense reactions is well documented. The non expressor of PR1 gene (NPR1) and the transcription factor TGA1 are redox-controlled key regulators of systemic acquired resistance. NPR1 monomers interact with the reduced form of TGA1, which targets the as-1 element of the promoter region of defense proteins.

We are analysing the effect of nitric oxide on the NPR1/TGA1 regulation system. We want to know how NO regulates nuclear translocation of NPR1 and what the functional und structural consequences of NO-dependent modification of both proteins are.

Christian Lindermayr

NO-dependent transport of NPR1-GFP into the nucleus. Protoplasts of plants stably transformed with a 35S:NPR1-GFP construct were isolated and treated with water, 100 μM GSNO, 100 μM cPTIO, 100 μM GSNO + 100 μM cPTIO or 250 μM salicylic acid for 20h. Localisation of NPR1-GFP fusion protein was analysed with a fluorescence microscope (200x). Protoplasts of plants stably transformed with a 35S:GFP construct were used as control to demonstrate that the different treatments have no effect of GFP. (Lindermayr et al., 2010)