Lyso-phosphatidylethanolamine-enhanced phenylalanine ammonia-lyase and insoluble acid invertase in isolated radish cotyledons

Hong, J.H. and Chung, J.H. and Cowan, A.K. (2009) Lyso-phosphatidylethanolamine-enhanced phenylalanine ammonia-lyase and insoluble acid invertase in isolated radish cotyledons. Plant Growth Regulation, 57 (1). pp. 69-78. ISSN 0167-6903

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Official URL: http://dx.doi.org/10.1007/s10725-008-9323-2

Abstract

Application of lyso-phosphatidylethanolamine (LPE) is purported to suppress fruit ripening and delay foliar senescence. However, the endogenous LPE response of plants is more typically associated with propagation of wound and stress signals. Experiments were therefore carried out to determine whether exogenous LPE could elicit defense responses in plants by determining the effect of this lyso-phospholipid on activity of two key metabolic enzymes and pathogenesis-related proteins viz phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and insoluble acid invertase (Ac INV; EC 3.2.1.26) in expanding cotyledons of Raphanus sativus L. cv. Cherry Belle (radish). Activity of both enzymes was increased following exposure of tissue to 18:0-LPE and the response was dose dependent. Soluble Ac INV activity was not enhanced by exogenous 18:0-LPE. Increased PAL activity appeared to coincide with a decline in phenolic acid content and a rise in sinapine and lignin. An increase in insoluble Ac INV by 18:0-LPE was associated with a reduction in sucrose concentration. However, levels of glucose and fructose were unaffected. In view of these findings it is proposed that applied LPE acts to co-ordinate carbohydrate partitioning locally to fulfill anabolic respiratory requirements associated with the propagation of systemic wound and stress responses. Furthermore, the impact of exogenous 18:0-LPE on insoluble Ac INV activity is discussed in relation to the proposed role of this enzyme in cytokinin-mediated senescence delay.

Item Type:Article
Additional Information:The original publication is available at www.springerlink.com
Uncontrolled Keywords:Acid invertase; Lyso-phosphatidylethanolamine; Phenylalanine ammonia-lyase; Raphanus sativus
Subjects:Y Unknown > Subjects to be assigned
Divisions:Research Institutes and Units > Environmental Biotechnology Research Unit (EBRU)
ID Code:1411
Deposited By: Mrs Eileen Shepherd
Deposited On:01 Jul 2009
Last Modified:06 Jan 2012 16:20
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