EPR-detected NO biosynthesis via nitrate reductase in non-climacteric pepper fruit: downregulation by ripening, peroxynitrite and H2S
This study presents the first direct evidence of nitric oxide (•NO) production in ripening pepper fruits (Capsicum annuum L.) and identifies the specific enzyme responsible for its generation. By clarifying the enzymatic origin of •NO, this research enhances our understanding of the redox signaling...
| Authors: | , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2026 |
| Country: | España |
| Institution: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repository: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:dnet:digitalcsic_::a040abbfbf3ae552eff688bd8e26830f |
| Online Access: | http://hdl.handle.net/10261/428695 |
| Access Level: | Open access |
| Keyword: | Hydrogen sulfide Nitric oxide Nitrate reductase Pepper fruits Peroxynitrite Ripening |
| Summary: | This study presents the first direct evidence of nitric oxide (•NO) production in ripening pepper fruits (Capsicum annuum L.) and identifies the specific enzyme responsible for its generation. By clarifying the enzymatic origin of •NO, this research enhances our understanding of the redox signaling mechanisms involved in the development of non-climacteric pepper fruits. Using electron paramagnetic resonance (EPR) spectroscopy combined with a spin-trapping technique, •NO production was directly detected at various stages of ripening. Enzymatic assays confirmed that the nitrite- and NADH (reduced nicotinamide adenine dinucleotide)-dependent nitrate reductase (NR) activity is responsible for the •NO generation, while RNA sequencing (RNA-Seq) identified a single nitrate reductase (CaNR) gene as the likely source of •NO. A recombinant CaNR protein was expressed and demons |
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