Npr1-flox Mouse

Npr1, or Nonexpressor of pathogenesis-related genes 1, is a key activator of salicylic acid (SA)-mediated immune responses in plants [2]. It plays a central role in systemic acquired resistance, a broad-spectrum disease resistance mechanism, and controls about 90% of SA-dependent transcriptome in Arabidopsis [4]. It is also involved in regulating the crosstalk between SA and other defense and growth hormones, thus being crucial for plant health [2].

In plants, Npr1 promotes cell survival during pathogen effector-triggered immunity (ETI) by forming salicylic acid-induced Npr1 condensates (SINCs). These SINCs target substrates for ubiquitination and degradation, such as EDS1 and specific WRKY transcription factors, through the formation of the Npr1-Cullin 3 E3 ligase complex [1]. Npr1 also functions as a transcriptional co-activator, binding to SA and bridging two TGA transcription factor dimers to form an enhanceosome for transcriptional induction [2,3]. Additionally, Npr1 and its paralogs have been defined as SA receptors, and Npr1's functions in stress protein homeostasis and cell survival are achieved through the formation of distinct nuclear and cytoplasmic biomolecular condensates [2].

In conclusion, Npr1 is a master regulator in plant immunity, with functions in transcriptional regulation, substrate ubiquitination, and cell survival decisions. Understanding Npr1 in plants can potentially be utilized to engineer resistance against biotic and abiotic stresses in crops [2].