J.-P. Roustan

École Nationale Supérieure Agronomique de Toulouse, Tolosa de Llenguadoc, Midi-Pyrénées, France

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Publications (28)

  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzyl aldehyde, is a toxin produced byEutypa lata,the causal agent of eutypa dieback of grapevines. It has previously been demonstrated that tolerance of some cultivars to this disease was correlated with their capacity to convert eutypine to the corresponding alcohol, eutypinol, which lacks phytotoxicity. We have thus purified to homogeneity a protein fromVigna radiatathat exhibited eutypine-reducing activity and have isolated the corresponding cDNA. This encodes an NADPH-dependent reductase of 36 kDa that we have namedVigna radiataeutypine-reducing enzyme (VR-ERE), based on the capacity of a recombinant form of the protein to reduce eutypine into eutypinol. The strongest homologies (86.8%) of VR-ERE at the amino acid level were found with CPRD14, a drought-inducible gene of unknown function, isolated fromVigna unguiculataand with an aromatic alcohol dehydrogenase (71.7%) fromEucalyptus gunnii. Biochemical characterization of VR-ERE revealed that a variety of compounds containing an aldehyde group can act as substrates. However, the highest affinity was observed with 3-substituted benzaldehydes. Expression of aVR-EREtransgene inVitis viniferacells culturedin vitroconferred resistance to the toxin. This discovery opens up new biotechnological approaches for the generation of grapevines resistant to eutypa dieback.
    Full-text Article · Oct 2008 · The Plant Journal
  • A. Bernadac · A. Latché · J.-P. Roustan · [...] · J.-C. Pech
    Chapter · Dec 2002
  • J.P. Roustan · S. Colrat · S. Dalmayrac · [...] · A. Latché
    [Show abstract] [Hide abstract] ABSTRACT: Eutypa dieback, caused by the ascomycete fungus Eutypa lata, is currently the most serious disease of the grapevine. This disease affects a great number of vineyards throughout the world and its economic impact is very important. Furthermore, there is no remedy available for the destruction of parasitic fungus. Eutypa lata infects the vineyard through pruning wounds and colonizes trunk or arms. It has been found that the fungus synthesizes a toxin, 4-hydroxy-3-(3-methyl-3-butene-l-ynyl) benzyl aldehyde, named eutypine. It is transported by the sap to the herbaceous parts of the grapevines and plays a prominent role in the expression of eutypa dieback symptoms. In the grapevine cells, eutypine is metabolized into an compound identified as 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzylic alcohol, named eutypinol. This compound does not exhibit a toxic effect towards the grapevine. Furthermore, a relationship has been found between tolerance to this disease and the capacity of cells to convert eutypine to the corresponding alcohol. The progress made in the understanding eutypine mechanism of action has opened new prospects regarding development of efficient tools for stopping this disease. We described here the purification to homogeneity of a protein from Vigna radiata that exhibited eutypine reductase activity and the cloning of corresponding cDNA. VR-ERE (eutypine reducing enzyme) cDNA encodes an NADPH-dependent reductase of 36 kDa exhibiting a high affinity towards eutypine. Furthermore, it has been shown that expression of the VR-ERE cDNA in grapevine cells, transformed by Agrobactehum-mediated procedure, conferred resistance to the toxin. This discovery opens up new biotechnological approaches for the generation of grapevines resistant to eutypa dieback.
    Article · May 2000 · Acta horticulturae
  • Source
    Ségolène Colrat · Alain Latché · Monique Guis · [...] · J.-P. Roustan
    [Show abstract] [Hide abstract] ABSTRACT: Eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzaldehyde) is a toxin produced by Eutypa lata, the causal agent of eutypa dieback in the grapevine (Vitis vinifera). Eutypine is enzymatically converted by numerous plant tissues into eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol), a metabolite that is nontoxic to grapevine. We report a four-step procedure for the purification to apparent electrophoretic homogeneity of a eutypine-reducing enzyme (ERE) from etiolated mung bean (Vigna radiata) hypocotyls. The purified protein is a monomer of 36 kD, uses NADPH as a cofactor, and exhibits a Km value of 6.3 &mgr;M for eutypine and a high affinity for 3- and 4-nitro-benzaldehyde. The enzyme failed to catalyze the reverse reaction using eutypinol as a substrate. ERE detoxifies eutypine efficiently over a pH range from 6.2 to 7.5. These data strongly suggest that ERE is an aldehyde reductase that could probably be classified into the aldo-keto reductase superfamily. We discuss the possible role of this enzyme in eutypine detoxification.
    Full-text Article · Feb 1999 · Plant physiology
  • S. Colrat · C. Deswarte · A. Latché · [...] · J. P. Roustan
    [Show abstract] [Hide abstract] ABSTRACT: Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzaldehyde, is a toxin produced by Eutypa lata (Pers.: Fr.) Tul., the causal agent of dying arm disease of Vitis vinifera L. (grapevine). Previously, we have shown that eutypine is involved in the development of disease symptoms. In the present study, the effects of V. vinifera cell-suspension cultures on the biological activity of the toxin were investigated. Eutypine was converted by grapevine tissues into a single compound, identified by mass spectrometry and nuclear magnetic resonance as 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzyl alcohol, designated eutypinol. This compound was found to be non-toxic for grapevine tissues. Unlike eutypine, eutypinol failed to affect the oxidation rate or membrane potential of isolated mitochondria. In grapevine cells, reduction of eutypine into the corresponding alcohol is an NADPH-dependent enzymatic reaction. An enzyme which reduced eutypine was partially purified, over 1000-fold, using a five-step purification procedure. By gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protein was found to have a molecular mass of 54–56 kDa. The enzyme exhibited an apparent K m for eutypine of 44 μM, and was active between pH 6.8 and 7.5 with a maximum at pH 7.0. The eutypine reductase activity was improved by Mn2+ and Mg2+ and inhibited by disulfiram and p-hydroxymercuribenzoate. The possible role of the eutypine-detoxification mechanism in the defense reactions of V. vinifera cells is discussed.
    Article · Feb 1999 · Planta
  • [Show abstract] [Hide abstract] ABSTRACT: Eutypa dieback, caused by the ascomycete fungus Eutypa lata (Pers.: Fr.) Tul. and C. Tul. is currently the most serious disease of the grapevine. It affects a great number of vineyards throughout the world and is becoming the primary constraint on vineyard longevity and can also indirectly affect the quality of wine (Moller and Kasimatis, 1981; Munkvold et al. 1994). To date no active chemicals are available for the destruction of the parasitic fungus in the plant. Eutypa dieback is only managed by practices such as removing and destroying infectea plants, delaying pruning, and protecting pruning wounds (Fallot et al. 1997). However, these practices are labour intensive, expensive and poorly efficient.
    Chapter · Jan 1999
  • [Show abstract] [Hide abstract] ABSTRACT: Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzyl aldehyde, is a toxin produced by Eutypa lata, the causal agent of eutypa dieback of grapevines. It has previously been demonstrated that tolerance of some cultivars to this disease was correlated with their capacity to convert eutypine to the corresponding alcohol, eutypinol, which lacks phytotoxicity. We have thus purified to homogeneity a protein from Vigna radiata that exhibited eutypine-reducing activity and have isolated the corresponding cDNA. This encodes an NADPH-dependent reductase of 36 kDa that we have named Vigna radiata eutypine-reducing enzyme (VR-ERE), based on the capacity of a recombinant form of the protein to reduce eutypine into eutypinol. The strongest homologies (86.8%) of VR-ERE at the amino acid level were found with CPRD14, a drought-inducible gene of unknown function, isolated from Vigna unguiculata and with an aromatic alcohol dehydrogenase (71.7%) from Eucalyptus gunnii. Biochemical characterization of VR-ERE revealed that a variety of compounds containing an aldehyde group can act as substrates. However, the highest affinity was observed with 3-substituted benzaldehydes. Expression of a VR-ERE transgene in Vitis vinifera cells cultured in vitro conferred resistance to the toxin. This discovery opens up new biotechnological approaches for the generation of grapevines resistant to eutypa dieback.
    Article · Dec 1998 · The Plant Journal
  • M. B. Amor · M. Guis · A. Latché · [...] · J.-P. Roustan
    [Show abstract] [Hide abstract] ABSTRACT: The role of ethylene in shoot regeneration was investigated using transgenic Cucumis melo plants expressing an antisense 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene. ACC oxidase catalyses the last step of ethylene biosynthesis. Leaf and cotyledon explants from the transgenic plants exhibited low ACC oxidase activity and ethylene production, whereas the regeneration capacity of the tissues was greatly enhanced (3.5- and 2.8-fold, respectively) compared to untransformed control tissues. Addition of ethylene released by 50 or 100 µm 2-chloroethylphosphonic acid dramatically reduced the shoot regeneration rate of the transgenic tissues. The results clearly demonstrate that ethylene plays an important role in C. melo morphogenesis in vitro.
    Article · Apr 1998 · Plant Cell Reports
  • Fallot J · Deswarte C · Dalmayrac S · [...] · Roustan J.-P
    Article · Feb 1997 · Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie
  • [Show abstract] [Hide abstract] ABSTRACT: Eutypine is a toxin produced by Eutypa lata, the causal agent of the dying-arm disease of grapevine. We have previously shown that this toxin behaves as a lipophylic weak acid (pK = 6.2) and induces drastic changes in both the respiration and energy balance of grapevine cells. In the present study, the molecular mode of action of eutypine at the mitochondrial level, using methyl-eutypine, the unprotonable derivative of the toxin, has been investigated. The effects of these molecules on mitochondrial respiration and membrane potential were compared using isolated mitochondria from grapevine cells in suspension cultures or potato tuber mitochondria. Eutypine induces marked stimulation of oxygen consumption and a depolarizing effect, while methyl-eutypine exhibits a very small effect on both the rate of oxygen uptake and membrane potential. For high eutypine concentrations, a mixed effect corresponding to a direct inhibition of electron transport and uncoupling can be observed. In addition, below 200 microM, eutypine displays a linear relationship between oxidation rate and membrane potential similar to that of the classical protonophore carbonyl cyanide-m-chlorophenylhydrazone (CCCP). However, unlike CCCP, eutypine induces a potential-dependent proton conductance that can be due to the potential-dependent migration of the dissociated form of the toxin across the membrane. It is concluded that eutypine uncouples mitochondrial oxidative phosphorylation and decreases the ADP/O ratio in grapevine cells by increasing the proton leaks via a cyclic protonophore mechanism. The physiological aspects of these results are discussed.
    Article · Nov 1996 · Archives of Biochemistry and Biophysics
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The plant hormone ethylene plays a major role in the ripening of climacteric fruit. We have generated transgenic cantaloupe Charentais melons expressing an antisense ACC oxidase gene; ACC oxidase catalyzes the last step of ethylene biosynthesis. Ethylene production of transgenic fruit was < 1% of control untransformed fruit, and the ripening process was blocked both on and off the vine. The antisense phenotype could be reversed by exogenous ethylene treatment. Analysis of antisense ACC oxidase melons indicated that the ripening process includes ethylene-dependent and ethylene-independent pathways. Because the transgenic line we generated displays extended storage life and improved quality, it has a promising potential for commercial development.
    Full-text Article · Aug 1996 · Nature Biotechnology
  • A Sarrafi · J P Roustan · J Fallot · G Alibert
    [Show abstract] [Hide abstract] ABSTRACT: Crosses were made between five cytoplasmic male-sterile and five restorer sunflower inbred lines. Twenty-five F1 hybrids and their parents were studied for their organogenesis ability in a randomized block design with four replications. Each replication per genotype consisted of ten petri dishes with four expiants. Regeneration medium consisted of full MS medium modified by the addition of hormones and solidified with 6 g/l agar. Statistical analysis showed that both general and specific combining abilities were significant for all of the organogenesis parameters studied, and both showed several significant positive or negative values. General combining ability values were usually higher than those of specific combining ability, indicating the importance of additive genetic control for organogenesis parameters in sunflower. Narrow-sense heritability for the number of explants producing shoots and roots was 65.8%, which suggests that organogenesis of currently inferior inbred lines in sunflower should be improved in a crossing program.
    Article · Feb 1996 · Theoretical and Applied Genetics
  • O. Soulie · V. Dulenc · J.-P. Roustan · J. Fallot
    [Show abstract] [Hide abstract] ABSTRACT: 2-Chloroethylphosphonic acid (ACEP) causes an inhibition of development of grapevine microcuttings (Vitis vinifera L. cv. Ugni blanc), and an increase in ethylene concentration into atmosphere of culture vessels; when it reaches 4.1 nmoles·l-1, growth is totally blocked. The inhibition of development is proportional to ethylene concentration. On the other hand, inhibition of ethylene action by silver ion allows to restore the development of microcuttings treated by inhibitory concentrations of ACEP. Furthermore, it has been demonstrated that microcuttings present a great sensitivity to ethylene only during the first days of culture.
    Article · Jan 1994
  • X. Xuhan · A Souvré · J P Roustan · [...] · J Fallot
    Article · Jan 1994 · Cytologia
  • Article · Jan 1994
  • O. Soulie · J.P. Roustan · J. Fallot
    Article · Jan 1993
  • O. Soulie · J.-P. Roustan · J. Fallot
    [Show abstract] [Hide abstract] ABSTRACT: The gazeous environment and especially ethylene accumulation in air-tight containers where tissues or plants are grown has been shown to affect growth and development of plants [1] and the regeneration from tissues or cells: maize [2], carrot [3] and sunflower [4]. In grapevine in vitro plants, the CO2 content of atmosphere was studied [5], but ethylene production and effects of this hormone on the micropropagation have not be elucidated. In this study, the relationship between ethylene production, ethylene effect and opening of axillary buds and root formation was investigated in Vitis vinifera in vitro plants.
    Chapter · Jan 1993
  • J.-P. Roustan · K. M. Chraibi · A. Latché · J. Fallot
    [Show abstract] [Hide abstract] ABSTRACT: We have previously shown that ethylene inhibits carrot somatic embryogenesis and sunflower organogenesis [1,2,3]. The role of ethylene in plant regeneration is still not clear. However, it has been suggested that polyamines play an important role in the process of somatic embryogenesis [4,5]. Also, in this study, the relationship between ethylene production, polyamine biosynthesis and plant regeneration was investigated in carrot cells and sunflower tissues.
    Chapter · Jan 1993
  • Article · Jan 1992
  • [Show abstract] [Hide abstract] ABSTRACT: The effects of CoCl2, AgNO3 and ethylene released by exogenous 2-chloroethylphosphonic acid (Ethephon), were studied on shoot regeneration from cotyledons of Helianthus annuus cv. E8206R, a poorly regenerative cultivar. Inhibition of ethylene biosynthesis by CoCl2, at concentrations of 20 μK, provoked a substantial enhancement of shoot regeneration (30 %): the control was poorly regenerative. However, CoCl2 had no effect when Ethephon was supplied. Inhibition of ethylene action by AgNO3, at concentrations of 10-25 μM, caused a significant increase in plant regeneration: 25 % instead of 1.2 % in the control. Furthermore, addition of Ethephon to AgNO3-treated tissues failed to reduce the stimulation of shoot regeneration caused by AgNO3. On the basis of these findings, it is suggested that ethylene inhibits the regeneration process from cotyledons of sunflower.
    Article · Jul 1991 · Plant Cell Reports