Nitrogen Depletion Blocks Growth Stimulation Driven by the Expression of Nitric Oxide Synthase in Tobacco

Abstract

Nitric oxide (NO) is a messenger molecule widespread studied in plant physiology. Latter evidence supports the lack of a NO-producing system involving a NO synthase (NOS) activity in higher plants. However, a NOS gene from the unicellular marine alga Ostreococcus tauri (OtNOS) was characterized in recent years. OtNOS is a genuine NOS, with similar spectroscopic fingerprints to mammalian NOSs and high NO producing capacity. We are interested in investigating whether OtNOS activity alters nitrogen metabolism and nitrogen availability, thus improving growth promotion conditions in tobacco. Tobacco plants were transformed with OtNOS under the constitutive CaMV 35S promoter. Transgenic tobacco plants expressing OtNOS accumulated higher NO levels compared to siblings transformed with the empty vector, and displayed accelerated growth in different media containing sufficient nitrogen availability. Under conditions of nitrogen scarcity, the growth promoting effect of the OtNOS expression is diluted in terms of total leaf area, protein content and seed production. It is proposed that OtNOS might possess a plant growth promoting effect through facilitating N remobilization and nitrate assimilation with potential to improve crop plants performance.

A biostimulant prepared from red seaweed Kappaphycus alvarezii induces flowering and improves the growth of Pisum sativum grown under optimum and nitrogen-limited conditions

“…Hoagland solution was used as a source of macro and micronutrients ( Nejamkin et al., 2020 ). The different treatments were arranged in a randomised block design on a metal bench in a greenhouse maintained at 24 ± 3°C by the fan and evaporative pad cooling system linked with temperature sensor and plants were grown under a natural day-light cycle.…”

Arginine as the sole nitrogen source for Ostreococcus tauri growth: Insights on nitric oxide synthase enzyme

“…The OtNOS expression promotes E. coli growth in a complete nutrient medium and provides a more efficient metabolization of L-Arg as an N source (Correa-Aragunde et al, 2022). Furthermore, the expression of OtNOS under the control of the Cauliflower Mosaic Virus (CaMV) in Nicotiana tabacum enhances growth and seed production, suggesting that OtNOS expression in plants has a straight impact on N metabolism (Nejamkin et al, 2020).…”

Chimera of Globin/Nitric Oxide Synthase: Toward Improving Nitric Oxide Homeostasis and Nitrogen Recycling and Availability

“…Otherwise, it is known that other pterins can fulfill NOS activity ( Presta et al., 1998 ). Recently, Nejamkin et al. (2020) have shown that the expression of the NOS from the algae Ostreococcus tauri (OtNOS) in tobacco increases growth rate, number of flowers and seed yield, and that this phenotype is lost when plants are grown in low N condition.…”