Potato tuber suberization

Roberts E. Kutchan T. Kolattukudy P. E. (1988) Cloning and sequencing of cDNA for a highly anionic peroxidase from potato and the induction of its mRNA in suberizing potato tubers and tomato fruits / / Plant Mol. Biol. V. 11. P. 15-26... 

In suberizing potato tuber disks, labeled oleic acid was incorporated into co-hy-droxyoleic acid and the corresponding dicarboxylic acid, the two major aliphatic components of potato suberin [73]. Exogenous labeled acetate was also incorporated into all of the aliphatic components of suberin, including the very long chain acids and alcohols in the wound-healing potato slices. The time-course of incorporation of the labeled precursors into the suberin components was consistent with the time-course of suberization. The biosynthetic pathway for the major aliphatic components of suberin is shown in Fig. 8a. 

The unique suberin components that are not found as significant components of cutin are the very long chain molecules and the dicarboxylic acids. Therefore, chain elongation and conversion of co-hydroxy acids to the corresponding dicarboxylic acids constitute two unique biochemical processes involved in the synthesis of suberin. Incorporation of labeled acetate into the very long chain components of suberin was demonstrated and this ability developed during suberization in potato tuber disks [73]. The enzymes involved... 

Fig. 18. Proposed structure of the active site of

Agrawal V P, Kolattukudy P E 1977 Biochemistry of suberization. coHydroxy acid oxidation in enzyme preparations from suberizing potato tuber disks. Plant Physiol 59 667-672... 

Cottle W, Kolattukudy P E 1982 Abscisic acid stimulation of suberization. Induction of enzymes and deposition of polymeric components and associated waxes in tissue cultures of potato tuber. Plant Physiol 70 775-780... 

Espelie K E, Franceschi V R, Kolattukudy P E 1986 Immunocytochemical localization and time course of appearance of an anionic peroxidase associated with suberization in wound-healing potato tuber tissue. Plant Physiol 81 487-492... 

Robards A W, Clarkson D T, Sanderson J 1979 Structure and permeability of the epider-mal/hypodermal layers of the sand sedge Carex arenaria L.). Protoplasma 101 331-347 Robards A W, Jackson S M, Clarkson D T, Sanderson J 1973 The structure of barley roots in relation to the transport of ions into the stele. Protoplasma 77 291-311 381a Roberts E, Kutchan T, Kolattukudy P E 1988 Cloning and sequencing of cDNA for a highly anionic peroxidase from potato and the induction of its mRNA in suberizing potato tubers and tomato fruits. Plant Mol Biol 11 15-26... 

Using a spectrophotometric assay to detect feruloyl-CoA transferase activity in enzymic extracts of 7-day suberized potato tuber discs, we tested a series of fatty alcohols or acids as potential acceptors of the feruloyl moiety (Table 1). 

HHT activity was not detectable in intact potato tuber tissue but was induced upon wounding after a lag period of three days (Fig.2). The time course of induction of HHT was therefore comparable with the kinetics of accumulation of alkyl ferulates [3] and of deposition of the aliphatic components of suberin [1]. HHT activity being restricted to the outermost cell layers of the wound-healing tuber discs, the development of HHT activity was both temporally and spatially coincident with the suberization process. The... 

The compound is not effective when appHed as a preharvest dormancy agent on potatoes and it should not be used until injuries to the tuber coat have healed. Neither should it be appHed until some suberization has occurred, generally two weeks after storage at >10° C (23). CIPC is widely used outside the United States on a number of crops as a herbicide. 

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