Protein S-nitrosylation in plants under biotic stress

Nitric oxide (NO) is a signaling molecule which controls a variety of biological functions and plays important roles in plant physiology. NO is involved in the majority of plant responses to biotic and abiotic stress, either indirectly through gene activation or interaction with hormones and reactive oxygen species (ROS), or directly as a result of altering enzyme activities primarily through S-nitrosylation. Protein S-nitrosylation is a redox-based post-translational modification that involves covalent attaching of a NO molecule to a reactive cysteine thiol of a target protein. This modification performs many significant physiological functions of NO. However, S-nitrosylation is a conserved evolutionary mechanism that regulates various facts of cellular signaling such as hormone signaling and responses to pathogens. It is challenging to find S-nitrosylated proteins since the S-NO bond is labile and therefore, methods to identify these modified proteins becomes difficult under different pathological conditions. Biotin switch method is well known in identifying S-nitrosylated proteins. S-nitrosylation of proteins plays important role in regulating different cellular processes like signal transduction, autophagy, SUMOylation and also impacts pathogen's virulence. However, much about S-nitrosylation is known due to abiotic stress. This short review highlights S-nitrosylation in response to biotic disturbances.