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Protein phosphorylation is suppressed when wheat embryos are hydrated and remain growth arrested

Published online by Cambridge University Press:  22 February 2007

Ryan L. Wagner  and
M.K. Walker-Simmons
Ryan L. Wagner
Affiliation:
USDA-ARS, Wheat Genetics, Quality, Physiology and Disease Research Unit, Washington State University, Pullman, WA, 99164-6420, USA
M.K. Walker-Simmons*
Affiliation:
Present address: Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.
*
*Correspondence Fax: +1 301?504 6191, Email:, [email protected]
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Abstract

An early difference in net protein phosphorylation activity occurred in dormant and after-ripened wheat (Triticum aestivum L.) grains within the first hour of imbibition at 30°C. Embryos from dry, dormant and after-ripened caryopses exhibited a high degree of protein phosphorylation, particularly of four proteins (68, 54, 51 and 42 kDa). Upon hydration, protein phosphorylation activity in dormant embryos decreased within 1 h and reached minimal phosphorylation activity by 5 h. Protein phosphorylation activity in after-ripened (germinable) embryos was not suppressed and remained high during germination. If the hydrated dormant embryos were dried, protein phosphorylation activity was restored. Application of the protein phosphatase inhibitor, okadaic acid, partially overcame dormancy and slowed the decrease in phosphorylation activity. These results suggested that reduction of protein phosphorylation activity slowed the rate of germination.

Keywords

dormancygerminationokadaic acidprotein phosphataseprotein phosphorylationTriticum aestivum
Type
Research Article
Information
Seed Science Research , Volume 14 , Issue 3 , September 2004 , pp. 287 - 296
Copyright
Copyright © Cambridge University Press 2004

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