Abstract
Nitric oxide (NO) modulates plant response to biotic and abiotic stresses by S-nitrosylation-mediated protein post-translational modification. Nitrate reductase (NR) and S-nitrosoglutathione reductase (GSNOR) enzymes are essential for NO synthesis and the maintenance of Nitric oxide/S-nitroso glutathione (NO/GSNO) homeostasis, respectively. S-nitrosoglutathione, formed by the S-nitrosylation reaction of NO with glutathione, plays a significant physiological role as the mobile reservoir of NO. The genome-wide analysis identified nine NR(NIA) and three GSNOR genes in the wheat genome. Phylogenic analysis revealed that the nine NIA genes +were clustered into four groups and the 3 GSNORs into two groups. qRT-PCR expression profiling of NIAs and GSNORs was done in Chinese spring (CS), a leaf rust susceptible wheat line showing compatible interaction, and Transfer (TR), leaf rust-resistant wheat line showing incompatible interaction, post-inoculation with leaf rust pathotype 77–5 (121-R-63). All the NIA genes showed upregulation during incompatible interaction in comparison with the compatible reaction. The GSNOR genes showed a variable pattern of expression: the TaGSNOR1 showed little change, whereas TaGSNOR2 showed higher expression during the incompatible response. TaGSNOR3 showed a rise of expression both in compatible and incompatible reactions. Before inoculation and after 72 h of pathogen inoculation, NO localization was studied in both compatible and incompatible reactions. The S-nitrosothiol accumulation, NR, and glutathione reductase activity showed a consistent increase in the incompatible interactions. The results demonstrate that both NR and GSNOR plays significant role in defence against the leaf rust pathogen in wheat by modulating NO homeostasis or signalling.
Highlights
Nitric oxide (NO) modulates plant response to biotic and abiotic stresses by S-nitrosylationmediated protein post-translational modification
Based on the genome-wide identification and expression profiling of Nitrate reductase (NR) and GSNOR genes and NO localization, nitrosothiol accumulation, NR, and Glutathione reductase (GR) activities, we found that NR and GSNOR family genes play a significant role in defence against the wheat leaf rust pathogen
Resistance reaction promoted the degradation of GSSG by increasing the activity of GR, thereby increasing the content of GSH, improving the antioxidant capacity of the plant
Summary
Nitric oxide (NO) modulates plant response to biotic and abiotic stresses by S-nitrosylationmediated protein post-translational modification. Nitrate reductase (NR) and S-nitrosoglutathione reductase (GSNOR) enzymes are essential for NO synthesis and the maintenance of Nitric oxide/Snitroso glutathione (NO/GSNO) homeostasis, respectively. The genome-wide analysis identified nine NR (NIA) and three GSNOR genes in the wheat genome. All the NIA genes showed upregulation during incompatible interaction in comparison with the compatible reaction. The results demonstrate that both NR and GSNOR plays significant role in defence against the leaf rust pathogen in wheat by modulating NO homeostasis or signalling. In the case of ETI, the effector molecules released by the pathogen are recognized directly or indirectly by the R gene product and results in localized cell death known as the hypersensitive response (HR)[7]. Nitric oxide plays an essential role in plant immunity by activating the pathogenesis-related proteins in plants[12]. GSNOR is established as one of the key players in the plant immune system in A rabidopsis[18]
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