This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (26) Citing Articles via Google Scholar Google Scholar Articles by Dulson, J. Articles by Johnston, R. N. Search for Related Content PubMed PubMed Citation Articles by Dulson, J. Articles by Johnston, R. N. Agricola Articles by Dulson, J. Articles by Johnston, R. N.

Metabolism and Enzymology

Abscisic Acid Is an Endogenous Inhibitor in the Regulation of Mannanase Production by Isolated Lettuce (Lactuca sativa cv Grand Rapids) Endosperms ¹

Department of Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada

The production of mannanase, a cell-wall-degrading carbohydrase, can be manipulated in isolated lettuce (Lactuca sativa cv Grand Rapids) endosperms by changes in the volume of buffer in which they are incubated. The enzyme is produced when endosperms are incubated in a large volume, but not when incubated in a small volume, which is suggestive that an endogenous, diffusible inhibitor of mannanase production is being lost from the endosperms in a large volume (JD Bewley, P Halmer 1980/1981 Israel J Bot 29: 118-132). We have investigated the possibility that the phytohormone abscisic acid (ABA) is involved in this regulation of mannanase production in isolated lettuce endosperms. We find several correlations between the presence of the endogenous inhibitor and of ABA, i.e. (a) a `leachate' prepared from isolated lettuce endosperms induces synthesis of ABA-specific proteins in barley aleurone layers, indicating that incubation of endosperms in a large volume results in the diffusion of ABA therefrom into the surrounding medium; (b) fractionation of the components of a leachate by either polyvinylpyrrolidone-chromatography of C₁₈ reversed-phase high performance liquid chromatography fails to separate the endogenous inhibitor from authentic ABA; and (c) changes in the incubation volume of endosperms result in changes in the amount of extractable ABA in the endosperms, as detected by ELISA. These results are consistent with a role for endogenous ABA in the regulation of mannanase production in isolated lettuce endosperms.

³ Present address: Department of Botany, University of Guelph, Guelph, Ontario N1G 2W1, Canada.

¹ Supported by National Sciences and Engineering Research Council of Canada grant A2210. This work was completed as part of her Ph.D. studies by J. D., while in receipt of a Natural Sciences and Engineering Research Council of Canada (NSERC) Postgraduate Award, a Ralph Steinhauer Award of Distinction and a Sir Izaak Walton Killam Memorial Honorarium.

This article has been cited by other articles:

				J. Argyris, P. Dahal, E. Hayashi, D. W. Still, and K. J. Bradford Genetic Variation for Lettuce Seed Thermoinhibition Is Associated with Temperature-Sensitive Expression of Abscisic Acid, Gibberellin, and Ethylene Biosynthesis, Metabolism, and Response Genes Plant Physiology, October 1, 2008; 148(2): 926 - 947. [Abstract] [Full Text] [PDF]

				N. Tamura, T. Yoshida, A. Tanaka, R. Sasaki, A. Bando, S. Toh, L. Lepiniec, and N. Kawakami Isolation and Characterization of High Temperature-Resistant Germination Mutants of Arabidopsis thaliana Plant Cell Physiol., August 1, 2006; 47(8): 1081 - 1094. [Abstract] [Full Text] [PDF]

				T. Gonai, S. Kawahara, M. Tougou, S. Satoh, T. Hashiba, N. Hirai, H. Kawaide, Y. Kamiya, and T. Yoshioka Abscisic acid in the thermoinhibition of lettuce seed germination and enhancement of its catabolism by gibberellin J. Exp. Bot., January 1, 2004; 55(394): 111 - 118. [Abstract] [Full Text] [PDF]