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Nitrated Cyclic GMP Modulates Guard Cell Signaling in Arabidopsis
Takahiro Joudoi, Yudai Shichiri, Nobuto Kamizono, Takaaki Akaike, Tomohiro Sawa, Jun Yoshitake, Naotaka Yamada and Sumio Iwai
The Plant Cell
Vol. 25, No. 2 (FEBRUARY 2013), pp. 558-571
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/41812288
Page Count: 14
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Nitric oxide (NO) is a ubiquitous signaling molecule involved in diverse physiological processes, including plant senescence and stomatal closure. The NO and cyclic GMP (cGMP) cascade is the main NO signaling pathway in animals, but whether this pathway operates in plant cells, and the mechanisms of its action, remain unclear. Here, we assessed the possibility that the nitrated cGMP derivative 8-nitro-cGMP functions in guard cell signaling. Mass spectrometry and immunocytochemical analyses showed that abscrsic acid and NO induced the synthesis of 8-nitro-cGMP in guard cells in the presence of reactive oxygen species. 8-Nitro-cGMP triggered stomatal closure, but 8-bromoguanosine 3',5'-cyclic monophosphate (8-bromo-cGMP), a membrane-permeating analog of cGMP, did not However, in the dark, 8-bromo-cGMP induced stomatal opening but 8-nitro-cGMP did not. Thus, cGMP and its nitrated derivative play different roles in the signaling pathways that lead to stomatal opening and closure. Moreover, inhibitor and genetic studies showed that calcium, cyclic adenosine-5'-diphosphate-ribose, and SLOW AION CHANNEL1 act downstream of 8-nitro-cGMP. This study therefore demonstrates that 8-nitro-cGMP acts as a guard cell signaling molecule and that a NO/8-nitro-cGMP signaling cascade operates in guard cells.
The Plant Cell © 2013 American Society of Plant Biologists (ASPB)