S-nitrosated proteomic analysis reveals the regulatory roles of protein S-nitrosation and S-nitrosoglutathione reductase during Al-induced PCD in peanut root tips.

Nitric oxide-mediated S-nitrosation through S-nitrosoglutathione reductase (GSNOR) plays important roles in cellular processes and signaling of plants; however, the regulatory mechanism of programmed cell death (PCD) by S-nitrosation remains unclear. In this study, the S-nitrosated proteomic and functions of GSNOR during Al-induced PCD in peanut were investigated. Al stress induced an increase of S-nitrosothiol (SNO) content and GSNOR activity in Al-induced PCD. There was significant positive correlation between SNO content and hydrogen peroxide content. The S-nitrosated proteomic analysis identified 402 S-nitrosated proteins containing 551 S-nitrosated sites during Al-induced PCD in the root tips of peanut. These S-nitrosated proteins were involved in regulation of various biological processes including energy metabolism, maintenance of cell wall function and organic acid secretion. Among them, 128 S-nitrosated proteins were up-regulated and one was down-regulated after Al stress. Experiments with recombinant AhGSNOR revealed that activity of the enzyme was inhibited by its S-nitrosation, with a moderate decrease of 17.9 % after 100 μM GSNO incubation. These data provide novel insights to understanding the functional mechanism of NO-mediated S-nitrosation during plant PCD.