Dissecting the correlation of ascorbate and nitric oxide on flowering in Oncidium and Arabidopsis
Date Issued
2012
Date
2012
Author(s)
Wu, Pei-Ying
Abstract
Flowering in Oncidium was supervised by the levels of endogenous carbohydrates and ascorbate (AsA) in the pseudobulb. To investigate the flowering mechanism, we carried out the transcriptomic profiles of axillary bud combined with proximal pseudobulb (APB) tissue and inflorescence bud combined with proximal pseudobulb (IPB) tissue at bolting period. Through the next generation sequencing (NGS) technology to approach the flowering mechanism, it revealed that nitric oxide (NO) metabolism-related genes were down-regulated significantly in IPB. NITRATE REDUCTASE (NAR) and NO SYNTHASE (NOS) exhibited lower gene expression levels and enzymatic activities at bolting period, leading to a reduction of NO level. Sodium nitroprusside (SNP), a NO donor, could repress Oncidium bolting and indicate that NO acts as negative regulator on Oncidium flowering. Intriguingly, exogenous AsA could trigger NO production by enhancing the enzymatic activities of NaR and NOS. In addition, vtc1, an AsA-deficient mutant of Arabidopsis, exhibited a deprived ability to induce NO by decreasing NaR activity. Noteworthily, exogenous SNP retrieved the flowering time of vtc1, but exogenous AsA could not rescue the flowering time of Arabidopsis NOS mutant, noa1. In conclusion, the regulation of flowering by NO might be a conservative cause in plant, the evidence suggests that NO acts as one of the downstream signal molecules underlying ASA effects on flowering processes in Arabidopsis and might be in Oncidium.
Subjects
Arabidopsis
ascorbate acid
flowering
nitric oxide
Oncidium Gower Ramsey
transcriptome
Type
thesis
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