NPR1

NPR1 (Nonexpressor of Pathogenesis-Related Genes 1) is a key protein in the plant immune system. It is a transcriptional coactivator that plays a crucial role in the systemic acquired resistance (SAR) pathway, which is a type of plant immune response.

Structure

NPR1 is a 66-kDa protein that contains ankyrin repeat domains and a BTB/POZ domain. The ankyrin repeat domains are involved in protein-protein interactions, while the BTB/POZ domain is involved in protein degradation.

Function

NPR1 is activated in response to pathogen attack. When a plant is infected, it produces salicylic acid (SA), which triggers the SAR pathway. NPR1 is then modified by reduction of a disulfide bond, leading to a change in its conformation and activation. Once activated, NPR1 moves into the nucleus where it interacts with TGA transcription factors to activate the expression of pathogenesis-related (PR) genes. These genes encode proteins that help the plant resist the pathogen.

Role in Disease Resistance

NPR1 has been shown to be essential for the induction of SAR in plants. Mutations in the NPR1 gene can make plants more susceptible to disease. Conversely, overexpression of NPR1 can enhance disease resistance. This has led to the use of NPR1 as a target for genetic engineering to improve crop resistance to pathogens.

See Also

• Plant immunity
• Systemic acquired resistance
• Salicylic acid
• Pathogenesis-related proteins