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Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
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Nitric oxide participates in plant flowering repression by ascorbate.
Rajendran Senthil Kumar1, Chin-Hui Shen1, Pei-Yin Wu1
1Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan.
Scientific Reports
|October 13, 2016
Summary
Floral repression in Oncidium orchids is linked to increased nitric oxide (NO) levels, mediated by ascorbic acid (AsA). This study reveals NO
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Redox homeostasis, particularly involving ascorbic acid (AsA), plays a role in Oncidium flowering.
- Nitric oxide (NO) signaling is increasingly recognized for its regulatory functions in plant development.
Purpose of the Study:
- To investigate the role of ascorbic acid (AsA)-mediated nitric oxide (NO) levels in the floral repression of Oncidium.
- To elucidate the molecular mechanisms underlying NO-mediated regulation of flowering in orchids.
Main Methods:
- Solexa transcriptomic analysis to identify differentially expressed genes in NO metabolism.
- Enzymatic activity assays for nitrate reductase (NaR) and nitrite reductase (NiR).
- Application of AsA and NO donors/scavengers in Oncidium and Arabidopsis mutants.
Main Results:
- Increased AsA levels correlate with elevated NO production, leading to floral repression in Oncidium.
- Downregulation of NaR and NiR gene expression and activity coincides with the bolting and blooming stages.
- NO signaling is crucial for flowering repression, as evidenced by late flowering in Arabidopsis mutants treated with NO donors and unaffected flowering in NO-deficient mutants treated with AsA precursors.
Conclusions:
- Oncidium flowering is tightly regulated by AsA-mediated NO levels.
- The downregulation of NO metabolism genes is a key factor in Oncidium bolting.
- NO signaling is vital for repressing flowering, with AsA being essential for NO biosynthesis in this pathway.
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