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Book ChapterDOI

Lipid-Derived Defensive Polymers and Waxes and Their Role in Plant–Microbe Interaction

01 Jan 1987-pp 291-314
TL;DR: The results obtained with the crude solubilized preparations supported the previous conclusions that multiple elongating systems are present in the membrane preparations and suggested that different chain-elongating enzyme systems are involved in their synthesis.
Abstract: Publisher Summary This chapter discusses lipid-derived defensive polymers and waxes and their role in plant-microbe interaction. Elongation of fatty acids by cell-free preparations from epidermal cells, where alkanes are known to be generated, has been demonstrated. Thus, microsomal preparations generate > C 20 acids from acyl-CoA using malonyl-CoA and NADPH as substrates. Although long acids with chain lengths approaching those of the alkanes can be generated by some of the cell-free preparations, chain length distribution of the products generated in vitro does not often correspond to that of the alkanes. As the epidermis generates many classes of lipids, each with its own characteristic chain length distribution, it is likely that different chain-elongating enzyme systems are involved in their synthesis. The different cell-free preparations so far studied contain more than one elongating system. The results obtained with the crude solubilized preparations supported the previous conclusions that multiple elongating systems are present in the membrane preparations.
Citations
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Book ChapterDOI
01 Jan 1991
TL;DR: There is good evidence that the cuticle is penetrated by the attacking pathogen before the sequential steps of disease development are halted by the active defense reactions of the challenged plant.
Abstract: Most plant-pathogenic fungi gain access into their host by penetration of unwounded tissue Some pathogens such as rusts invade the host via stomata (Hoch and Staples, 1987 and Chapter 2), whereas others penetrate the intact leaf surface without the requirement of natural openings (Aist, 1976; Emmett, 1975; Kunoh, 1984) The latter type of direct penetration encounters the plant cuticle, a noncellular hydrophobic structure covering the layer of epidermal cells The cuticle thus serves as the first surface barrier that the pathogen has to breach There is little evidence for the mere physical strength of the plant cuticle as a major factor in plant defense against pathogens In some cases, the thickness of plant cuticles has been correlated with an increased passive resistance against fungal attack This correlation, however, appears to be an exception rather than the rule (Martin, 1964) Furthermore, the cuticle has not been considered to play a major role in the active defense mechanisms of disease-resistant cultivars There is good evidence that the cuticle is penetrated by the attacking pathogen before the sequential steps of disease development are halted by the active defense reactions of the challenged plant Recent examples for this lack of cuticle involvement in cultivar resistance are the host—pathogen interactions of Venturia ivaequalis—apple (Valsangiacomo and Gessler, 1988) or Phytophthora infestans—potato (Gees and Hohl, 1987) The breaching of the cuticle can also be accomplished in many interactions of pathogens with nonhost plants (Heath, 1987)

502 citations

BookDOI
TL;DR: This work presents a meta-analyses of the molecular Basis of Candida Pathogenicity and its relationships with Virulence in the Early Stages of Phaeohyphomycosis, and the role of cuticle-Degrading Enzymes in Fungal Pathogenesis in Insects.
Abstract: I. Spore Attachment and Invasion.- 1. Adhesion of Fungi to the Plant Surface: Prerequisite for Pathogenesis.- 2. Signaling for Infection Structure Formation in Fungi.- 3. The Plant Cell Wall as a Barrier to Fungal Invasion.- 4. Rust Basidiospore Germlings and Disease Initiation.- 5. Attachment of Mycopathogens to Cuticle: The Initial Event of Mycoses in Arthropod Hosts.- 6. The Fate of Fungal Spores in the Insect Gut.- 7. Candida Blastospore Adhesion, Association, and Invasion of the Gastrointestinal Tract of Vertebrates.- 8. Infectious Propagules of Dermatophytes.- II. Fungal Spore Products and Pathogenesis.- 9. Melanin Biosynthesis: Prerequisite for Successful Invasion of the Plant Host by Appressoria of Colletotrichum and Pyricularia.- 10. The Plant Cuticle: A Barrier to Be Overcome by Fungal Plant Pathogens.- 11. Appearance of Pathogen-Related Proteins in Plant Hosts: Relationships between Compatible and Incompatible Interactions.- 12. The Role of Cuticle-Degrading Enzymes in Fungal Pathogenesis in Insects.- 13. Potential for Penetration of Passive Barriers to Fungal Invasion in Humans.- 14. Dihydroxynaphthalene (DHN) Melanin and Its Relationship with Virulence in the Early Stages of Phaeohyphomycosis.- III. Host Response to Early Fungal Invasion.- 15. Invasion of Plants by Powdery Mildew Fungi, and Cellular Mechanisms of Resistance.- 16. Induced Systemic Resistance in Plants.- 17. The Plant Membrane and Its Response to Disease.- 18. The Fungal Spore: Reservoir of Allergens.- 19. Conidia of Coccidioides immitis: Their Significance in Disease Initiation.- 20. Cell-Mediated Host Response to Fungal Aggression.- 21. Suppression of Phagocytic Cell Responses by Conidia and Conidial Products of Aspergillus fumigatus.- IV. Molecular Aspects of Disease Initiation.- 22. Molecular Approaches to the Analysis of Pathogenicity Genes from Fungi Causing Plant Disease.- 23. Current Status of the Molecular Basis of Candida Pathogenicity.- Taxonomic Index.

417 citations


Cites background from "Lipid-Derived Defensive Polymers an..."

  • ...More recently, Kunoh and colleagues (1988) demonstrated that Erysiphe graminis conidia release a liquid film within minutes of contact with a barley leaf....

    [...]

Journal ArticleDOI
01 Jun 1996
TL;DR: Among the topics discussed are the partitioning of fatty acid precursors into wax biosynthesis and the elongation of fatty acids with particular emphasis on the nature of the acyl primer, and the role of ATP in fatty acid elongation.
Abstract: The aerial surfaces of plants are covered with a wax layer that is primarily a waterproof barrier but that also provides protection against environmental stresses. The ubiquitous presence of cuticular wax is testimony to its essential function. Genetic and environmental factors influence wax quantity and composition, which suggests that it is an actively regulated process. The basic biochemistry of wax production has been elucidated over the past three decades; however, we still know very little about its regulation. This review presents a discussion along with new perspectives on the regulatory aspects of wax biosynthesis. Among the topics discussed are the partitioning of fatty acid precursors into wax biosynthesis and the elongation of fatty acids with particular emphasis on the nature of the acyl primer, and the role of ATP in fatty acid elongation. The recent cloning of wax biosynthetic genes and the transport of wax to plant surfaces are also discussed.

413 citations

Book ChapterDOI
TL;DR: The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens.
Abstract: Polyesters occur in higher plants as the structural component of the cuticle that covers the aerial parts of plants. This insoluble polymer, called cutin, attached to the epidermal cell walls is composed of interesterified hydroxy and hydroxy epoxy fatty acids. The most common chief monomers are 10, 16-dihydroxy C16 acid, 18-hydroxy-9, 10 epoxy C18 acid, and 9, 10, 18-trihydroxy C18 acid. These monomers are produced in the epidermal cells by ω hydroxylation, in-chain hydroxylation, epoxidation catalyzed by P450-type mixed function oxidase, and epoxide hydration. The monomer acyl groups are transferred to hydroxyl groups in the growing polymer at the extracellular location. The other type of polyester found in the plants is suberin, a polymeric material deposited in the cell walls of a layer or two of cells when a plant needs to erect a barrier as a result of physical or biological stress from the environment, or during development. Suberin is composed of aromatic domains derived from cinnamic acid, and aliphatic polyester domains derived from C16 and C18 cellular fatty acids and their elongation products. The polyesters can be hydrolyzed by pancreatic lipase and cutinase, a polyesterase produced by bacteria and fungi. Catalysis by cutinase involves the active serine catalytic triad. The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens. Transcriptional regulation of cutinase gene in fungal pathogens is being elucidated at a molecular level. The polyesters present in agricultural waste may be used to produce high value polymers, and genetic engineering might be used to produce large quantities of such polymers in plants.

403 citations

Journal ArticleDOI
TL;DR: This work believes to be the first evidence indicating separate depositional patterns, at the cellular level, for the two major domains of suberin and separate roles for each of these domains in the development of resistance to bacterial and fungal infection during suberization.

183 citations

References
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Journal ArticleDOI
30 May 1980-Science
TL;DR: The biosynthesis of the hydroxy, epoxy, and dicarboxylic acids of the polyesters from the common cellular fatty acids is elucidated and the function and possible practical implications of these polyester barriers are briefly discussed.
Abstract: Cutin, a biopolyester composed of hydroxy and epoxy fatty acids, is the barrier between the aerial parts of higher plants and their environment. Suberin a polymer containing aromatics and polyesters, functions as a barrier in underground parts, wound surfaces, and a variety of internal organs. The composition and probable structure of these polymers are discussed. The biosynthesis of the hydroxy, epoxy, and dicarboxylic acids of the polyesters from the common cellular fatty acids is elucidated. An extracellular enzyme transfers the hydroxy and epoxyacyl moieties from their coenzyme A derivatives to the growing polyester. The enzymes acting in the biodegradation of the polyesters have been isolated from fungi, pollen, and mammals and characterized. The function and possible practical implications of these polyester barriers are briefly discussed.

782 citations

Journal ArticleDOI
TL;DR: This chapter shall review recent advances in understanding the nature of the barrier layers and the mechanism of fungal penetration of such barriers, and indicates that the soluble waxes associated with the polymers can play a significant role in the host-pathogen interaction.
Abstract: Cuticle and suberized periderm form barriers that protect plants against ingress by pathogens. The entry of bacteria and viruses into plants usually requires wounds , whereas many fungal pathogens can penetrate the intact barriers. The mode of fungal penetration of the cuticular barrier has been a subject of controversy for the better part of a century, as summarized a decade ago in this series (70). The past decade has seen considerable progress in understanding the nature of the barrier layers and the mechanism of fungal penetration of such barriers . In this chapter I shall review these recent advances; earlier studies have been reviewed previously (2, 48, 49, 60, 70). S ince the insoluble polymeric structural components constitute the main physical obstacle to fun­ gal penetration, this review will focus on these polymers. Although there are indications that the soluble waxes associated with the polymers can play a significant role in the host-pathogen interaction, these chemical interactions remain largely unknown and therefore will not be covered in this chapter. Although successful pathogenesis often involves penetration of the pathogen not only through the cuticle but also through the cell wall, this review is confined to the outer barrier.

299 citations

Journal ArticleDOI
28 Sep 1984-Botany
TL;DR: Natural and wound periderms and a variety of internal barrier layers contain a somewhat analogous polymer called suberin, which is probably composed of aromatic domains somewhat similar to those found in lignin and aliphatic polyester domains somewhatSimilar to cutin.
Abstract: Cutin, the structural component of plant cuticle, is a biopolyester composed of hydroxy- and hydroxyepoxy-fatty acids The major monomers are a 16-hydroxy C16 acid, a 10,16-dihydroxy C16 acid toget

296 citations

Journal ArticleDOI
TL;DR: The present results support the hypothesis that this anionic peroxidase is involved in the deposition of the aromatic polymeric domain of suberin.
Abstract: Thin sections of wound-healing potato tuber tissue were stained with rabbit antibody prepared against a suberization-associated anionic peroxidase and then stained with a goat anti-rabbit antibody-fluorescein conjugate. When these sections were examined with an epiilluminating fluorescence microscope, bright green fluorescent linear deposits were observed on the inner side of cell walls in the periderm layer. Initial deposits which were often not contiguous throughout the wall were first observed in some cells after 3 days of wound-healing and subsequently these layers became more pronounced so that all 6 day old periderm cells had green fluorescent layers on their inner walls. This fluorescence was not present in the walls of parenchyma cells or in the walls of periderm cells treated with preimmune serum and anti-rabbit IgG-FITC conjugate. Thin sections of wound-healing potato tissue which were stained with anti-peroxidase antibody and a goat anti-rabbit antibody-rhodamine conjugate exhibited a similar time course of development with a bright reddish-orange fluorescent layer observed on the inside wall of periderm cells. The production of this suberization-associated anionic peroxidase in wound-healing tissue was also demonstrated by an immunobinding dot blot assay which showed that the largest increase in the enzyme level occurred between 4 and 6 days of wound-healing. The present results support the hypothesis that this anionic peroxidase is involved in the deposition of the aromatic polymeric domain of suberin.

296 citations

Journal ArticleDOI
TL;DR: It is concluded that the aldehydes produced by the acyl-CoA reductase located in the endomembranes of the epidermal cells are converted to alkanes by the decarbonylase Located in the cell wall/cuticle region.
Abstract: Mechanism of enzymatic conversion of a fatty acid to the corresponding alkane by the loss of the carboxyl carbon was investigated with particulate preparations from Pisum sativum. A heavy particulate preparation (sp. gr., 1.30 g/cm3) isolated by two density-gradient centrifugation steps catalyzed conversion of octadecanal to heptadecane and CO. Experiments with [1-3H,1-14C]octadecanal showed the stoichiometry of the reaction and retention of the aldehydic hydrogen in the alkane during this enzymatic decarbonylation. This decarbonylase showed an optimal pH of 7.0 and a Km of 35 microM for the aldehyde. This enzyme was severely inhibited by metal ion chelators and showed no requirement for any cofactors. Microsomal preparations and the particulate fractions from the first density-gradient step catalyzed acyl-CoA reduction to the corresponding aldehyde. Electron microscopic examination showed the presence of fragments of cell wall/cuticle but no vesicles in the decarbonylase preparation. It is concluded that the aldehydes produced by the acyl-CoA reductase located in the endomembranes of the epidermal cells are converted to alkanes by the decarbonylase located in the cell wall/cuticle region.

194 citations