prior to the upregulation of cold-related gene expression and antioxidant enzymes
activities in Medicago truncatula plants during cold stress tolerance. Further,
brassinolide inhibitor reduced NO production and the expression of brassinolideinduced mitochondrial alternative oxidase, photosystem II efficiency, and homeostasis secondary metabolites accumulation [128]. This suggests that production of
secondary metabolites or phytosignalling molecules may be the mechanism through
which NO exerts its protecting effect from abiotic stress in plants.
5
Conclusions
Alteration in secondary metabolism is an effective strategy of the plants to survive
and grow in adverse conditions [56]. Many studies indicated the influence of abiotic
stress on the amounts of phenolic compounds, flavonoids, glucosinolates, antioxidants, osmolytes, carotenoids terpene derivatives, and phytohormones in plants. NO
has been reported to be induced rapidly by abiotic and biotic elicitors in a variety of
plant species. Although several studies evidence the role of secondary metabolites
and NO in plant’s response to various abiotic stress factors, the knowledge about
NO-mediated secondary metabolome alterations in abiotic stressed plants is still
in its infancy. Few recent studies have shown that exogenous addition of NO can
enhance the effect of abiotic elicitors on plant secondary metabolite production.
Moreover, different NO donors could be chemically synthesized to be used as a
priming agents or elicitor for industrial production of important secondary metabolites in plant culture systems. The NO elicitation can be an effective strategy to
significantly improve specificity and efficiency of the production of desired metabolites. Hence, complete understanding of the signal transduction pathways underlying NO-induced production of secondary metabolites not only advance our
understanding but also is important for optimizing the commercial production of
metabolites which are difficult to be obtained by chemical synthesis.
Acknowledgments This work was supported by a financial support to authors from the CGIAR
Research Program on Genetic Gains.
References
1. Vile D, Pervent M, Belluau M, Vasseur F, Bresson J, Muller B, . . . Simonneau T (2012)
Arabidopsis growth under prolonged high temperature and water deficit: independent
or interactive effects. Plant Cell Environ 35(4):702–718. https://doi.org/10.1111/j.13653040.2011.02445
2. Santisree P, Bhatnagar-Mathur P, Sharma KK (2015) NO to drought-multifunctional role of
nitric oxide in plant drought: do we have all the answers. Plant Sci 239:44–55. https://doi.org/
10.1016/j.plantsci.2015.07.012
3. Monks PS, Archibald AT, Colette A, Cooper O, Coyle M, Derwent R, . . . Stevenson DS
(2015) Tropospheric ozone and its precursors from the urban to the global scale from air
quality to short-lived climate forcer. Atmos Chem Phys 15(15): 8889–8973. https://doi.org/
10.5194/acp-15-8889
25 Nitric Oxide as a Signal in Inducing Secondary Metabolites During Plant Stress
613
activities in Medicago truncatula plants during cold stress tolerance. Further,
brassinolide inhibitor reduced NO production and the expression of brassinolideinduced mitochondrial alternative oxidase, photosystem II efficiency, and homeostasis secondary metabolites accumulation [128]. This suggests that production of
secondary metabolites or phytosignalling molecules may be the mechanism through
which NO exerts its protecting effect from abiotic stress in plants.
5
Conclusions
Alteration in secondary metabolism is an effective strategy of the plants to survive
and grow in adverse conditions [56]. Many studies indicated the influence of abiotic
stress on the amounts of phenolic compounds, flavonoids, glucosinolates, antioxidants, osmolytes, carotenoids terpene derivatives, and phytohormones in plants. NO
has been reported to be induced rapidly by abiotic and biotic elicitors in a variety of
plant species. Although several studies evidence the role of secondary metabolites
and NO in plant’s response to various abiotic stress factors, the knowledge about
NO-mediated secondary metabolome alterations in abiotic stressed plants is still
in its infancy. Few recent studies have shown that exogenous addition of NO can
enhance the effect of abiotic elicitors on plant secondary metabolite production.
Moreover, different NO donors could be chemically synthesized to be used as a
priming agents or elicitor for industrial production of important secondary metabolites in plant culture systems. The NO elicitation can be an effective strategy to
significantly improve specificity and efficiency of the production of desired metabolites. Hence, complete understanding of the signal transduction pathways underlying NO-induced production of secondary metabolites not only advance our
understanding but also is important for optimizing the commercial production of
metabolites which are difficult to be obtained by chemical synthesis.
Acknowledgments This work was supported by a financial support to authors from the CGIAR
Research Program on Genetic Gains.
References
1. Vile D, Pervent M, Belluau M, Vasseur F, Bresson J, Muller B, . . . Simonneau T (2012)
Arabidopsis growth under prolonged high temperature and water deficit: independent
or interactive effects. Plant Cell Environ 35(4):702–718. https://doi.org/10.1111/j.13653040.2011.02445
2. Santisree P, Bhatnagar-Mathur P, Sharma KK (2015) NO to drought-multifunctional role of
nitric oxide in plant drought: do we have all the answers. Plant Sci 239:44–55. https://doi.org/
10.1016/j.plantsci.2015.07.012
3. Monks PS, Archibald AT, Colette A, Cooper O, Coyle M, Derwent R, . . . Stevenson DS
(2015) Tropospheric ozone and its precursors from the urban to the global scale from air
quality to short-lived climate forcer. Atmos Chem Phys 15(15): 8889–8973. https://doi.org/
10.5194/acp-15-8889
25 Nitric Oxide as a Signal in Inducing Secondary Metabolites During Plant Stress
613