Induction and Regulation of Ethylene Biosynthesis by Pectic Oligomers in Cultured Pear Cells

Campbell, Alan D.; Labavitch, John M.

doi:10.1104/pp.97.2.699

Cited by 55 publications

(21 citation statements)

References 29 publications

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“…In MG unripe fruit, B. cinerea secretes cell wall-degrading enzymes that target fruit wall polysaccharides (P. Shah, D. Cantu, A.L.T. Powell, R. Orlando, C. Bergmann, and G. Gutierrez, unpublished data), and products of the degradation of cell wall pectin in ripening tomatoes promote the production of ethylene and fruit ripening (Campbell and Labavitch, 1991;Melotto et al, 1994). Thus, B. cinerea itself may produce or cause the production of factors, in addition to ethylene, that indirectly induce fruit ripening.…”

Section: Discussionmentioning

confidence: 99%

Ripening-Regulated Susceptibility of Tomato Fruit toBotrytis cinereaRequiresNORBut NotRINor Ethylene

Cantu

Blanco‐Ulate

Long³

et al. 2009

Plant Physiology

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163

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Fruit ripening is a developmental process that is associated with increased susceptibility to the necrotrophic pathogen Botrytis cinerea. Histochemical observations demonstrate that unripe tomato (Solanum lycopersicum) fruit activate pathogen defense responses, but these responses are attenuated in ripe fruit infected by B. cinerea. Tomato fruit ripening is regulated independently and cooperatively by ethylene and transcription factors, including NON-RIPENING (NOR) and RIPENING-INHIBITOR (RIN). Mutations in NOR or RIN or interference with ethylene perception prevent fruit from ripening and, thereby, would be expected to influence susceptibility. We show, however, that the susceptibility of ripe fruit is dependent on NOR but not on RIN and only partially on ethylene perception, leading to the conclusion that not all of the pathways and events that constitute ripening render fruit susceptible. Additionally, on unripe fruit, B. cinerea induces the expression of genes also expressed as uninfected fruit ripen. Among the ripening-associated genes induced by B. cinerea are LePG (for polygalacturonase) and LeExp1 (for expansin), which encode cell wall-modifying proteins and have been shown to facilitate susceptibility. LePG and LeExp1 are induced only in susceptible rin fruit and not in resistant nor fruit. Thus, to infect fruit, B. cinerea relies on some of the processes and events that occur during ripening, and the fungus induces these pathways in unripe fruit, suggesting that the pathogen itself can initiate the induction of susceptibility by exploiting endogenous developmental programs. These results demonstrate the developmental plasticity of plant responses to the fungus and indicate how known regulators of fruit ripening participate in regulating ripening-associated pathogen susceptibility.

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Section: Discussionmentioning

confidence: 99%

Ripening-Regulated Susceptibility of Tomato Fruit toBotrytis cinereaRequiresNORBut NotRINor Ethylene

Cantu

Blanco‐Ulate

Long³

et al. 2009

Plant Physiology

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151

163

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“…This result suggests that even the nonelicited level of H,O, production is subject to down-regulation by the elicitorinduced desensitization. Induction of such a desensitized state is well known for various sensory systems in animals and has also been suggested and discussed to occur on elicitation of suspension-cultured cells of pear (Campbell and Labavitch, 1991), soybean (Legendre et al, 1993), tobacco (Mathieu et al, 1991), and tomato (Felix et al, 1993;Granado et al, 1995).…”

Section: Dlscusslonmentioning

confidence: 99%

Competence for Elicitation of H2O2 in Hypocotyls of Cucumber Is Induced by Breaching the Cuticle and Is Enhanced by Salicylic Acid

et al. 1996

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Georgia 30602-471 2 (M.G.H.)To study H,O, production, the epidermal surfaces of hypocotyl segments from etiolated seedlings of cucumber (Cucumis safivus L.) were gently abraded. Freshly abraded segments were not constitutively competent for rapid H,O, elicitation. This capacity developed subsequent to abrasion in a time-dependent process that was greatly enhanced in segments exhibiting an acquired resistance to penetration of their epidermal cell walls by Collefofricbum lagenarium, because of root pretreatment of the respective seedlings with 2,6-dichloroisonicotinic acid. When this compound or salicylic acid was applied t o abraded segments, it also greatly enhanced the induction of competence for H,O, elicitation. This process was fully inhibited by 5 PM cycloheximide or 200 PM puromycin, suggesting a requirement for translational protein synthesis. Both a crude elicitor preparation and a partially purified oligoglucan mixture from Pbyfophfbora sojae also induced, in addition t o H,O, production, a refractory state, which explains the transient nature of H,O, elicitation. Taken together, these results suggest that the cucumber hypocotyl epidermis becomes conditioned for competence t o produce H,O, i n response to elicitors by a stimulus resulting from breaching the cuticle and/or cutting segments. This conditioning process is associated with protein synthesis and is greatly enhanced when substances able t o induce systemic acquired resistance are present in the tissue.The interaction of plant cells with potentially pathogenic microorganisms is associated with rather complex biochemical and physiological events. Experiments on these processes are, therefore, often performed with simplified systems in which the pathogen is reduced to "elicitors" and the plant to a mechanically wounded tissue surface or to cell-suspension cultures. These models have already contributed many insights into the mechanisms of plant responses presumably related to defense but still require refinement to better cover the diverse biological features of host/pathogen interactions. It should be considered, for instance, that severa1 signals may act subsequently in the course of pathogenesis and that the nutritional status, age, or a previous infection of a plant can influence the effectiveness of defense responses.

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“…HPLC gradient analysis indicated tha G7 contained oligomers with a DP from 5 to 13, with 909i of carbohydrates in DP 7 to 9, and GI 2 contained oligomer from DP 6 to 19, with 90% in DP 10 to 12 (JM Labavitch LC Greve, unpublished data). The preparation and composi tion of these mixtures are described more fully elsewhere (9) The described experiments were repeated several times, anc typical results are reported. Discs from MG3 and MG4 frui behaved similarly; only results from MG4 fruit are shown.…”

Section: Application Of Treatmentsmentioning

confidence: 99%

Induction and Regulation of Ethylene Biosynthesis and Ripening by Pectic Oligomers in Tomato Pericarp Discs

Campbell¹,

Labavitch²

1991

Plant Physiol.

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The effect of pectic oligomers and 1-aminocyclopropane carboxylic acid on ethylene biosynthesis and color change was studied in ripening tomato pericarp discs excised from maturegreen tomato fruit (Lycopersicon esculentum Mill.). Pectic oligomers induced at least four distinct responses when added to pericarp discs: (a) a short-term, transient increase in ethylene biosynthesis; (b) a long-term, persistent increase in climacteric ethylene in discs excised from mature-green fruit; (c) an advance in ripening processes, as indicated by increased reddening of the disc surfaces; and (d) a darkening of the treated endocarp surface. Pectic oligomers appear to affect the ripening of exocarp and endocarp tissues by different mechanisms. In exocarp tissues, the acceleration of reddening by pectic oligomers might simply be a consequence of induced ethylene biosynthesis. In endocarp tissues, the acceleration of reddening appears to be a direct effect of oligomers on ripening processes. We suggest that the rate of ripening of endocarp tissues may be regulated, in part, by the release of pectic oligomers from the cell walls of adjacent exocarp tissues. Exocarp and endocarp tissues of pericarp discs appear to differ in their sensitivity to ethylene at each maturity stage, and to exhibit independent changes in sensitivity to ethylene as ripening progresses. The tissue-specific pattern of reddening in tomato pericarp may result from this differential sensitivity to endogenous ethylene concentrations.The phenomenon of climacteric ripening clearly encompasses a diverse set of physiological processes. In tomato fruit (Lycopersicon esculentum Mill.) obvious changes in color, texture, flavor, and aroma progress through an anatomically complex fruit in just a few days (2, 13). Color change in tomato occurs in a rather circuitous pattern. In a typical fruit, loss of chlorophyll and synthesis of lycopene begin in the locular or central columella tissues, emerge externally at the stylar end ofthe fruit, then spread rapidly across the superficial exocarp layer, before progressing into the underlying endocarp tissues (13,23). Changes in ethylene biosynthetic activity (4) and PG3 activity (26) have been recently shown to follow a '

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Induction and Regulation of Ethylene Biosynthesis by Pectic Oligomers in Cultured Pear Cells

Cited by 55 publications

References 29 publications

Ripening-Regulated Susceptibility of Tomato Fruit toBotrytis cinereaRequiresNORBut NotRINor Ethylene

Ripening-Regulated Susceptibility of Tomato Fruit toBotrytis cinereaRequiresNORBut NotRINor Ethylene

Competence for Elicitation of H2O2 in Hypocotyls of Cucumber Is Induced by Breaching the Cuticle and Is Enhanced by Salicylic Acid

Induction and Regulation of Ethylene Biosynthesis and Ripening by Pectic Oligomers in Tomato Pericarp Discs

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