Nitric oxide and selenium nanoparticles confer changes in growth, metabolism, antioxidant machinery, gene expression, and flowering in chicory (Cichorium intybusL.): potential benefits and risk assessment

This experiment was conducted to provide a better insight into the plant responses to nitric oxide (NO) and selenium nanoparticle (nSe). Chicory seedlings were sprayed with nSe (0, 4, and 40 mg l(-1)), and/or NO (0 and 25 mu M). NO and/or nSe4 improved shoot and root biomass by an average of 32%. The nSe40 adversely influenced shoot and root biomass (mean = 26%), exhibiting moderate toxicity partly relieved by NO. The nSe and NO treatments transcriptionally stimulated the dehydration response element B1A (DREB1A) gene (mean = 29.6-fold). At the transcriptional level, nSe4 or NO moderately upregulated phenylalanine ammonia-lyase (PAL) and hydroxycinnamoyl-CoA quinate transferase (HCT1) genes (mean = sevenfold). The nSe4 + NO, nSe40, and nSe40 + NO groups drastically induced the expression ofPALandHCT1genes (mean = 30-fold). With a similar trend, hydroxycinnamoyl-CoA Quinate/shikimate hydroxycinnamoyl transferase (HQT1) gene was also upregulated in response to nSe and/or NO (mean = 25-fold). The activities of nitrate reductase and catalase enzymes were also induced in the nSe- and/or NO-treated seedlings. Likewise, the application of these supplements associated with an increase in ascorbate concentration (mean = 31.5%) reduced glutathione (mean = 35%). NO and/or nSe enhanced the PAL activity (mean = 36.4%) and soluble phenols (mean = 40%). The flowering was also influenced by the supplements in dose and compound dependent manner exhibiting the long-time responses. It appears that the nSe-triggered signaling can associate with a plethora of developmental, physiological, and molecular responses at least in part via the fundamental regulatory roles of transcription factors, likeDREB1Aas one the most significant genes for conferring tolerance in crops.

Automated summary

This study investigated the responses of chicory seedlings to nitric oxide (NO) and selenium nanoparticles (nSe). Results showed that nSe40 negatively affected shoot and root biomass, while nSe4 and NO improved biomass. The transcriptional activation of key genes like DREB1A was observed in response to nSe and NO treatments, along with increased activities of enzymes like PAL and HCT1. Additionally, the supplementation of nSe and NO enhanced the PAL activity and soluble phenols, while also influencing flowering in a dose and compound dependent manner.