Calcium influxes and mitogen-activated protein kinase kinase activation mediate ethylene inducing ipomoelin gene expression in sweet potato
Resource
Plant, Cell & Environment 31 (1): 62-72
Journal
Plant Cell & Environment
Pages
071030013314001-???
Date Issued
2008
Date
2008
Author(s)
Abstract
The ipomoelin gene (IPO) was identified to be a wound-inducible gene from Ipomoea batatas, and its expression was stimulated by methyl jasmonate (MeJA) and hydrogen peroxide. IPO protein was also characterized as a defence-related protein, and it is also a carbohydrate-binding protein. In this study, the expression of IPO was used as a molecular probe to study the effects of Ca 2+ on the signal transduction of ethylene. A confocal microscope monitored the Ca2+ within cells, and Northern blotting examined IPO expression. The presence of Ca2+ channel blocker, including diltiazem, neomycin or ruthenium red, abolished the increase of cytosolic Ca2+, and reduced the IPO expression in the cells induced by ethylene. Furthermore, both Ca2+ influxes and IPO expression stimulated by ethylene were prohibited in the presence of 10 mm ethylene glycol-bis(2-aminoethyl ether)-N, N, N′, N′-tetraacetic acid (EGTA). These results indicated that Ca2+ influxes into the cytosol induced by ethylene are from both apoplast and organelles, and are required for activating IPO expression. However, in the presence of 1 mm EGTA, ethylene can still stimulate IPO expression, but mechanical wounding failed to do it. Therefore, Ca2+ channels in the plasma membrane induced by ethylene have higher affinity to Ca2+ than that stimulated by wounding. Moreover, the addition of A23187, an ionophore, raised cytosolic Ca 2+, but was unable to stimulate IPO expression. These findings showed that IPO induction did not solely depend on Ca2+, and Ca 2+ elevation in cytosol is necessary but not sufficient for IPO expression. The application of PD98059, a mitogen-activated protein kinase kinase (MAPKK) inhibitor, did not prevent Ca2+ from increasing in the cytosol induced by ethylene, but inhibited the IPO expression stimulated by staurosporine (STA), a protein kinase inhibitor. Conclusively, elevation of cytosolic Ca2+ by ethylene may stimulate protein phosphatase and MAPKK, which finally activates IPO expression. © 2007 The Authors.
Subjects
Calcium ion; Ethylene signalling; Membrane channel
Other Subjects
2 (2 amino 3 methoxyphenyl)chromone; calcium; egtazic acid; ethylene; ethylene derivative; flavonoid; ipomoelin protein, Ipomoea batatas; mitogen activated protein kinase kinase; unclassified drug; vegetable protein; antibiotics; calcium; carbohydrate; cation; enzyme activity; ethylene; gene expression; hydrogen peroxide; inhibitor; protein; tuber; vine; wounding; article; drug effect; enzyme activation; enzymology; gene expression regulation; genetics; metabolism; signal transduction; sweet potato; Calcium; Egtazic Acid; Enzyme Activation; Ethylenes; Flavonoids; Gene Expression Regulation, Plant; Ipomoea batatas; Mitogen-Activated Protein Kinase Kinases; Plant Proteins; Signal Transduction; Ipomoea batatas
Type
journal article
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