Nitric oxide-dependent regulation of sweet pepper fruit ripening

Abstract

Ripening is a complex physiological process that involves changes in reactive nitrogen and oxygen species that govern the shelf-life and quality of fruits. Nitric oxide (NO)-dependent changes in the sweet pepper fruit transcriptome were determined by treating fruits at the initial breaking point stage with NO gas. Fruits were also harvested at the immature (green) and ripe (red) stages. Fruit ripening in the absence of NO resulted in changes in the abundance of 8805 transcripts whose function could be identified. Among these, functional clusters associated with reactive oxygen/nitrogen species and lipid metabolism were significantly modified. NO treatment resulted in the differential expression of 498 genes framed within these functional categories. Biochemical analysis revealed that NO treatment resulted in changes in fatty acid profiling, glutathione and proline contents, and the extent of lipid peroxidation, as well as increases in the activity of ascorbate peroxidase and lipoxygenase. These data provide supporting evidence for the crucial role of NO in the ripening of pepper fruit.

Inhibition of NADP‐malic enzyme activity by H2S and NO in sweet pepper (Capsicum annuum L.) fruits

“…This is corroborated by the increase in protein nitration (Chaki et al ), S ‐nitrosation (Rodríguez‐Ruiz et al ) and lipid peroxidation observed in sweet pepper fruit (Chu‐Puga et al ). Furthermore, it has been shown that the exogenous NO gas application on sweet pepper fruit has an anti‐maturation effect because it reduced the content of oxidative stress marker such as lipid peroxidation whereas antioxidant systems increased including ascorbate and glutathione content as well as the ascorbate peroxidase activity (Rodríguez‐Ruiz et al , González‐Gordo et al ).…”

“…For example, NADPH oxidase (Rboh) activity involved in superoxide generation increased 5.3‐fold, which closely correlates with an increase in lipid peroxidation, a marker of oxidative stress associated with fruit ripening (Chu‐Puga et al ). On the other hand, proline (Pro) content, whose biosynthesis from glutamate by the Δ 1 ‐pyrroline 5‐carboxylate synthase (P5CS) enzyme specifically requires NADPH, has also been reported to increase during ripening (Signorelli and Monza , González‐Gordo et al ). It is important to note that the increase in Pro is related to the mechanisms of response to different plant stresses usually associated with oxidative stress conditions such as salinity (Bouthour et al 2015), drought (Signorelli et al ) or arsenic (Rodríguez‐Ruiz et al ), although Pro is not a direct scavenger of ROS (Signorelli et al ).…”

Assessment of Subcellular ROS and NO Metabolism in Higher Plants: Multifunctional Signaling Molecules

“…Both types of Trx regulate chloroplast redox homeostasis and interact with Prxs to establish a redox signal cascade and to modulate thiol groups [36]. A Trx combined with nitroreductase (NTR)at the C terminus is called NTRC, which, when involved in redox regulation, appears to affect starch and chlorophyll biosynthesis [41]. 1 O 2 scavenging chiefly occurs through reactions with biomolecules such as tocopherols [42], carotenoids [43], and membrane lipids [44].…”

“…As outlined above, ROS and NO play a crucial role in signaling mechanisms, which modulate plant growth and development, transpiration, hormonal regulation, germination, stomatal gaseous exchange, flowering, fruit ripening, defense responses, and programmed cell death (PCD) [41].…”

“…Using NO donors, such as GSNO and NO gas, as well as Arabidopsis plants exposed to GSNO through the root system, 1945 responsive genes differentially expressed in leaves and roots,114 of which corresponded to only one of these organs, were identified [178]. Modulation during pepper fruit ripening of roughly 2987 genes, 498 of which were modulated by NO, has also been studied [41].…”