Hippolyte Kodja

... D, Vandewalle P, Goffinet B, Luisetti J, Trigalet A. (2000b) Genetic diversity of Ralstonia solanacearum as assessed by PCR-RFLP of the hrp gene region, AFLP and 16S rRNA sequence analysis, and identification of an African subdivision. ... Thoquet P, Olivier J, Sperisen C et al. ...

Fungal endophytes are known to produce secondary metabolites. The synthesis of vanillin and its precursors have never been clearly elucidated. Given fungi can produce such metabolites, it is speculated that fungal endophytes in vanilla could be contributing to vanillin and its precursors. An investigation was thus carried to find whether fungal endophytes are present in Vanilla planifolia. Additionally, vanilla flavor varies across cultivation regions; hence, the distribution of endophytes across regions was also assessed and found to differ. The metabolic changes brought by the fungi on vanillin and its precursors in vanilla pods were also evaluated. Out of 434 isolated fungal endophytes, two candidates emerged: Pestalotiopsis microspora and Diaporthe phaseolorum. However, P. microspora increased the most the absolute amounts (quantified by 1H NMR in μmol/g DW green pods) of vanillin (37.0 × 10−3), vanillyl alcohol (100.0 × 10−3), vanillic acid (9.2 × 10−3), and p-hydroxybenzoic acid (87.9 × 10−3) when cultured on green pod-based media. Given the physical proximity of fungi inside pods, endophytic biotransformation may contribute to the complexity of vanilla flavors.

... Authors Fock, I.; Luisetti, J.; Collonnier, C.; Vedel, F.; Ducreux, G.; Kodja, H.; Sihachakr, D. Editors Allen, C.;Prior, P.;Hayward, AC Book Bacterial wilt disease and the Ralstonia solanacearum species complex 2005 pp. ... To learn more about our products please visit our website. ...

In this study, 58 endophytic bacterial strains were isolated from pods of two hybrid vanilla plants from Madagascar, Manitra ampotony and Tsy taitra. They were genetically characterized and divided into four distinct phylotypes. Three were associated to genus Bacillus species, and the fourth to the genus Curtobacterium. A selection of twelve strains corresponding to the identified genetic diversity were tested in vitro for four phytobeneficial capacities: phosphate solubilisation, free nitrogen fixation, and phytohormone and siderophore production. They were also evaluated in vitro for their ability to biocontrol the growth of the vanilla pathogenic fungi, Fusarium oxysporum f. sp. radicis vanillae and Cholletotrichum orchidophilum. Three bacteria of phylotype 4, m62a, m64 and m65, showed a high nitrogen fixation capacity in vitro, similar to the Pseudomonas florescens F113 bacterium used as a control (phospate solubilizing efficiency respectively 0.50 ± 0.07, 0.43 ± 0.07 and 0.40 ±...

Few studies have been conducted on endophytic bacteria of vanilla. In this study, 58 bacterial strains were isolated from two hybrid vanilla plants from Madagascar,Manitra ampotonyandTsy taitra. They were genetically characterised and divided into four distinct phylotypes. A selection of twelve strains corresponding to the identified genetic diversity were testedin vitrofor four phytobeneficial capacities: phosphate solubilisation, free nitrogen fixation, phytohormone and siderophore production. They were also evaluatedin vitrofor their ability to biocontrol the growth of the vanilla pathogenic fungi,Fusarium oxysporum f. sp. radicis vanillaeandCholletotrichum orchidophilum. Bacteria belonging to three different phyla were found to be highly competent in each of the phytobeneficial capacities tested. Bacteria belonging to the phylum related toBacillus siamensisshowed the best capacity to inhibit fungal growth making them good candidates for controlling fungal diseases of vanilla. Th...

The first part of the talk will be dedicated to the investigation of medicinal plants with the objective to identify new antimalarial treatments. According to the last World Malaria Report [1], there were 584 000 deaths for 198 millions malaria cases worldwide in 2013. Particularly, the disease caused an estimated 437 000 African children died before their fifth birthday, still in 2013. Malaria is caused by a parasite, Plasmodium sp. and transmitted by Anopheles mosquitoes. The problem of parasite resistance towards common available medicines such as chloroquine, mefloquine, quinine, is increasing. In this context, the vegetal kingdom remains the main source of pharmacologically active compounds against this parasitic infection as attested by the famous quinine, isolated from Cinchona sp., artemisinin extracted from Artemisia annua and also atovaquone derived from lapachol found in several Bignoniaceae. All these substances are related to plants with traditional use against fever and malaria. Beside these well-known examples, various new antiplasmodial compounds are frequently discovered from Nature, particularly following an ethnopharmacological approach, as reviewed by several authors in recent years [2-6]. Then, the pharmacological and phytochemical study of plants from traditional pharmacopoeias can be of first interest not only to discover new antimalarial “lead compounds”, but also to valorize local vegetal species whose efficacy and safety would have been demonstrated in laboratory and by clinical investigations [7,8]. Some results obtained with Dicoma tomentosa from Burkina-Faso [9] and Terminalia mollis from Rwanda [10] will be presented. In the second part of the talk, two applications of biotechnology for the production of artemisinin and paclitaxel and then some works developed at the ‘Université de la Réunion’ will be presented. In the framework of this collaboration, Psiadia arguta, an endemic plant from Reunion Island, which is known to have cytotoxic, anti-plasmodial and anti-inflammatory properties, was subjected to micropropagation. The objective of the work was to compare the biological properties and the phytochemical composition of callus, vitroplants and acclimatized plants of Psiadia arguta [11]. 1. WHO, World Malaria Report 2014, December 2014, Geneva (http://www.who.int/malaria/publications/world_malaria_report_2014/en/). 2. Batista R, Silva Ade J Jr, de Oliveira AB: Plant-derived antimalarial agents: new leads and efficient phytomedicines. Part II. Non-alkaloidal natural products. Molecules 2009, 14:3037-72. 3. Bero J, Frédérich M, Quetin-Leclercq J : Antimalarial compounds isolated from plants used in traditional medicine. Journal of Pharmacy and Pharmacology 2009, 61:1401–1433. 4. Bero J and Quetin-Leclercq J: Natural products published in 2009 from plants traditionally used to treat malaria. Planta Medica 2011, 77:631-40. 5. Kaur K, Jain M, Kaur T, Jain R: Antimalarials from nature. Bioorganic & Medicinal Chemistry 2009, 17:3229–3256. 6. Nogueira CR and Lopes LMX: Antiplasmodial Natural Products. Molecules 2011, 16:2146-2190 7. Ginsburg H and Deharo E: A call for using natural compounds in the development of new antimalarial treatments – an introduction. Malaria Journal 2011, 10 (suppl. 1):S1 8. Willcox M, Graz B, Falquet J, Diakite C, Giani S, Diallo D: A “reverse pharmacology” approach for developing an antimalarial phytomedicine. Malaria journal 2011, 10(suppl1):S8 9. Jansen, O., Tits, M., Angenot, L., Nicolas, J.-P., De Mol, P., Nikiema, J.-B., & Frédérich, M : Anti-plasmodial activity of Dicoma tomentosa (Asteraceae) and identification of urospermal A-15-O-acetate as the main active compound. Malaria Journal 2012, 11, 289. 10. Muganga, R., Angenot, L., Tits, M., & Frédérich, M : In vitro and in vivo antiplasmodial activity of three Rwandan medicinal plants and identification of their active compounds. Planta Medica 2013, 80(6), 482-489. 11. Mahy Justine, Comparative study of biological activities and analysis of volatile compounds of Psiadia arguta in various cultures: vitroplants and acclimatized plants. Mémoire de M2, 2013, Université de Liège/Université de la Réunion

Le Sugarcane yellow leaf virus (SCYLV), agent causal du syndrome de la feuille jaune de la canne a sucre, etait largement repandu a la Reunion en 1998. Les taux d'infection variaient de 10 a 100% selon les six lieux et les trois varietes commerciales etudies. Ces taux d'infection n'ont pas beaucoup varie de 1998 a 2000, suggerant ainsi que 1/ des differences varietales existent pour l'infection virale, 2/ la maladie est surtout disseminee par la plantation de boutures infectees, et non par des insectes vecteurs. L'evolution des populations virales in planta a ete etudiee a l'aide de boutures infectees. La distribution du SCYLV dans les tiges etait systemique et uniforme depuis la germination des boutures jusqu'a 10 mois de croissance, quelle que soit la variete. Si aucune difference de repartition du virus n'a ete mise en evidence entre varietes, des differences de densites de populations virales ne peuvent cependant pas etre exclues. (Resume d'au...

A la suite de la decouverte de nodules aeriens, formes au sein de protuberances nodulaires sur les troncs de Casuarina cunninghamiana, au nord de l'ile de la Reunion, on a entrepris une etude experiementale en vue de reproduire la formation de cette structure remarquable sur des plants de Casuarina cunninghamiana de 1 an cultives en serre ou de 4 mois cultives en in vitro. Moins d'un mois apres leur inoculation avec des nodules broyes provenant du champ ou avec une culture pure de Frankia ORS 021001, des nodules aeriens sont apparus sur les racines adventives

Suite aux etudes conduites au champ sur les nodules aeriens (protuberances portant des nodules) qui se developpent spontanement a l'ile de la Reunion sur les troncs des Casuarina cunninghamiana de 40 a 50 ans, une etude experimentale a ete conduite pour reproduire en serre et in vitro les conditions conduisant a la formation des nodules aeriens. En serre, les racines adventives ont pu etre produites sur la tiges des sl C. cunninghamiana et C. equisetifolia vieux d'un an en maintenant un taux eleve d'humidite sur la tige et apres inoculation par des nodules aeriens broyes preleves au champ. In vitro, 90% des plantules de C. cunninghamiana cultivees axeniquement ont developpe une moyenne de 2,5 racines adventives par tige pour les meilleurs traitements, y compris l'addition d'AIB. Les donnees experimentales confirment les conclusions des etudes au champ sur la conjonction de facteurs favorables pour induire chez Casuarina la formation de nodules aeriens fixateurs d'azote

The production of secondary metabolites from cell suspensions of P. arguta , an endangered endemic plant from  Mauritius has never been reported. In order to identity the optimum culture conditions, the effect of light and cytokinins on phenylpropanoid products was studied. These conditions were, exposure of cells to a 16hr photoperiod and culture in MS basic medium containing TDZ (2mg/l) +NAA (0.5mg/l). Under such conditions, the production of tannins and flavonoids was higher than observed in crude leaf extracts. These data show that TDZ, like in any morphogenic process, acts as a powerful cytokinin enhancing the phenylpropanoid pathway. Nevertheless, TDZ activity seems to be contradictory with respect to the production of 2-phenyl-4-H-1- benzopyran-4-one and tannic acid as opposed to 1,2 benzopyrone synthesis. Keywords : Psiadia arguta (Pers.)Voigt, Asteraceae , phenylpropanoid, 1,2- benzopyrone, 2-phenyl- 4-1-benzopyran-4-one, tannic acid, phenol, PAL, TDZ, BAP.

All files were generated, and can be opened, on MEGA 5.0 (http://www.megasoftware.net/) + MS Powerpoint. Phylogenetic relationships among the 23 identified MOTUs from fungal endophytes isolated from Vanilla planifolia. The analysis was based on LSU rDNA sequences

Background The objective of the work was to characterize fungal endophytes from aerial parts of Vanilla planifolia. Also, to establish their biotransformation abilities of flavor-related metabolites. This was done in order to find a potential role of endophytes on vanilla flavors. Results Twenty three MOTUs were obtained, representing 6 fungal classes. Fungi from green pods were cultured on mature green pod based media for 30 days followed by 1H NMR and HPLC-DAD analysis. All fungi from pods consumed metabolized vanilla flavor phenolics. Though Fusarium proliferatum was recovered more often (37.6 % of the isolates), it is Pestalotiopsis microspora (3.0 %) that increased the absolute amounts (quantified by 1H NMR in μmol/g DW green pods) of vanillin (37.0 × 10−3), vanillyl alcohol (100.0 × 10−3), vanillic acid (9.2 × 10−3) and p-hydroxybenzoic acid (87.9 × 10−3) by significant amounts. Conclusions All plants studied contained endophytic fungi and the isolation of the endophytes was conducted from plant organs at nine sites in Réunion Island including under shade house and undergrowth conditions. Endophytic variation occured between cultivation practices and the type of organ. Given the physical proximity of fungi inside pods, endophytic biotransformation may contribute to the complexity of vanilla flavors

Des prospections ont ete effectuees de 1998 a 2000 pour determiner la distribution et l'evolution du syndrome de la feuille jaune (YLS) a la Reunion. La technique des immuno-empreintes (IE) a ete utilisee pour detecter le sugarcane yellow leaf virus (SCYLV) dans trois principales varietes (R570. R575 et R579). Le virus etait largement repandu sur l'ile. Les taux d'infection ont varie de 10% a 100% selon la variete et le lieu, et sont restes relativement stables sur une periode de deux ans. Ces resultats suggerent qu'a la Reunion le niveau de resistance a la maladie differe en fonction des cultivars; que la canne a sucre infectee ne recupere pas de la maladie apres la recolte et que le virus est principalement transmis par la plantation de boutures infectees et non par l'intermediaire d'insectes vecteurs. La dynamique du SCYLV dans la plante a ete etudiee grâce a l'aide de boutures infectees de quatre varietes (R570, R575, R577 et R579) et deux techniques ...

Antimicrobial and molecular studies of three endemic medicinal plants from Mauritius L. tomentorii and L. purpureum and Lomatophyllum macrum from Reunion Island was carried out to differentiate them from Aloe vera which belongs to the same family Asphodelaceae. These endemic Aloes are used in the Mauritian and Reunion pharmacopoeia to treat bacterial infections and as antispasmodic.3 Phytochemical screening of the crude extracts revealed the common presence of alkaloids, anthraquinones, coumarins, phenols, saponins and tannins. Anthraquinones and saponins had also been reported as bioactive compounds present in Alooideae and in Aloe vera 1,4 .Antimicrobial activity was tested against Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus using the microplate dilution method. Extracts of Lomatophyllum species showed more potent antimicrobial activity than Aloe vera with MIC ranging 0.003-0.006mg/L as compared to 0.012-.0.028mg/L for Aloe vera .The antimicrobial properties of L. tormentorii and L. purpureum were attributed to the presence of alkaloids, coumarins, and saponins which are known to possess antimicrobial attributes. In this study we also used a modified RAPD-PCR technique. to elucidate the genetic closeness of Lomatophyllum to Aloe. Genomic DNA was extracted using a modification of the method used by Govinden-Soulange et al (2007)2. RAPD-PCR technique has revealed that Lomatophyllum species and Aloe vera share some genetic similarities. Consequently we report the genetic diversity of the Lomatophyllum species by measuring the genetic distance, which they have with Aloe vera. Moreover some biologically active compounds within the Lomatophyllum were identified and their possible similarities with Aloe vera were unveiled. Key Words: Biological activities, Lomatophyllum, Aloes, genetic distance References: 5. Atherton, P. (1999). Aloe vera: myth or medicine? Positive Health, 20 June/July. 6. Govinden-Soulange J, Ranghoo-Sanmukhiya M, Seeburrun SD. (2007). Tissue culture and RAPD analysis of Cinnamomum camphora and Cinnamomum verum. Biotechnology. 6(2):239-244 7. Gurib-Fakim, A. Gueho, J., Sewraj, M. and Dulloo, E. (1994). Plantes Medicinales de l’Ile Rodrigues. Editions de l’Ocean Indien, Maurice. 8. Mark, W.C., Anette, Y.D., Anthony, V.C., Gail, R., Paula, J.R. Margaret, A.T. and Lui, E.E. (2000). Phylogenetics of Asphodelaceae (Asparagales): Analysis of Plastid rbcL and trn-L-F DNA Sequences. Annals of Botany, 86: 935-951.

The metabolomic analysis of developing Vanilla planifolia green pods (between 3 and 8 months after pollination) was carried out by nuclear magnetic resonance (NMR) spectroscopy and multivariate data analysis. Multivariate data analysis of the (1)H NMR spectra, such as principal component analysis (PCA) and partial least-squares-discriminant analysis (PLS-DA), showed a trend of separation of those samples based on the metabolites present in the methanol/water (1:1) extract. Older pods had a higher content of glucovanillin, vanillin, p-hydroxybenzaldehyde glucoside, p-hydroxybenzaldehyde, and sucrose, while younger pods had more bis[4-(beta-D-glucopyranosyloxy)-benzyl]-2-isopropyltartrate (glucoside A), bis[4-(beta-D-glucopyranosyloxy)-benzyl]-2-(2-butyl)tartrate (glucoside B), glucose, malic acid, and homocitric acid. A liquid chromatography-mass spectrometry (LC-MS) analysis targeted at phenolic compound content was also performed on the developing pods and confirmed the NMR results...

Global trade increases plant introductions, but joint introduction of associated microbes is overlooked. We analyzed the ectomycorrhizal fungi of a Caribbean beach tree, seagrape (Coccoloba uvifera, Polygonacaeae), introduced pantropically to stabilize coastal soils and produce edible fruits. Seagrape displays a limited symbiont diversity in the Caribbean. In five regions of introduction (Brazil, Japan, Malaysia, Réunion and Senegal), molecular barcoding showed that seagrape mostly or exclusively associates with Scleroderma species (Basidiomycota) that were hitherto only known from Caribbean seagrape stands. An unknown Scleroderma species dominates in Brazil, Japan and Malaysia, while Scleroderma bermudense exclusively occurs in Réunion and Senegal. Population genetics analysis of S. bermudense did not detect any demographic bottleneck associated with a possible founder effect, but fungal populations from regions where seagrape is introduced are little differentiated from the Caribb...

The spread of Sugarcane yellow leaf virus (SCYLV) in sugarcane plants was studied on Reunion using virus-infected cuttings from four cultivars (R570, R575, R577 and R579). One month after the germination of cuttings in an insect-proof glasshouse, SCYLV was detected by reverse-transcription polymerase chain reaction (RT-PCR) and tissue-blot immunoassay (TBIA) in the leaves, shoots and roots of all cultivars. The distribution of SCYLV in the whole plant did not vary over a 10- to 11-month period of growth. In addition, the spread of SCYLV in sugarcane fields on Reunion was investigated during a survey conducted from 1998 to 2001. Samples were taken in three sugarcane-growing areas, and TBIA was used to detect SCYLV in the three major cultivars (R570, R575 and R579). The percentage of infected stalks varied according to cultivar and growing area, but remained relatively stable for a given cultivar in a given growing area over the 30-month survey period. Cultivar R575 was the most infec...

INTRODUCTION Aloe tormentorii, A. purpurea and A. macra are used as multipurpose folk medicines in Réunion and Mauritius Islands and are mistaken for the introduced Aloe vera. OBJECTIVE To compare the phytochemical, antimicrobial and DNA profiles of Aloe endemic to Mauritius and Réunion with the profiles of A. vera. Methodology - Leaf extracts of these Aloe species were analysed using standard phytochemical screening techniques, TLC and by HPLC. These extracts were also assayed for antimicrobial activity using microdilution techniques. Genetic diversity was studied using RAPD markers. RESULTS Phytochemical and antimicrobial assays and RAPD analysis showed that Mascarene Aloe species were very different from A. vera. CONCLUSION This study is the first report highlighting the differences between Aloe sp.p from Mascarene and Aloe vera at the metabolic and genomic level.

Psiadia arguta (Asteraceae) is endemic to the island of Mauritius in the Indian Ocean. The species is traditionally used to treat various ailments, such as its use as an expectorant or for the treatment of bronchitis and asthma. Preliminary biological screenings have displayed the antimalarial (Plasmodium falciparum) and anticancer (HeLa human cell line) potential of P. arguta leaves. The phytochemical investigation of this plant has led to the isolation and characterization of sixteen compounds including five antiplasmodial molecules. The accumulation of the antiplasmodial compounds during the growth of the plant was studied by a 1H NMR-based metabolomic approach. In order to identify factors influencing the production of bioactive compounds, young plants of P. arguta were multiplied using in vitro culture techniques, and micro-propagated plants at different stages of development were acclimatized and followed for the experiments. The multivariate data analysis showed an accumulation of four bioactive compounds in the leaves of P. arguta when these plants were challenged with a biotic stress: labdan-13(E)-en-8α-ol-15-yl acetate, labdan-8α-ol-15-yl acetate, labdan-13(E)-ene-8α-ol-15-diol, and (8R,13S)-labdan-8,15-diol.

An ethyl acetate extract of Psiadia arguta leaves showed in vitro antiplasmodial activity against Plasmodium falciparum with IC50 values of 12.3 ± 2.4 μg/mL (3D7 strain) and 13.5 ± 3.4 μg/mL (W2 strain). Phytochemical investigation led to the isolation and characterization of 16 compounds including four new diterpenoids: labdan-8α-ol-15-yl-(formate) (1), labdan-8α-ol-15-yl-(2-methylbutanoate) (2), labdan-8α-ol-15-yl-(3-methylpentanoate) (3), and labdan-8α-ol-15-yl-(labdanolate) (4). The latter compounds were characterized by spectroscopic methods (1D and 2D NMR, HRMS, and IR). The in vitro antiplasmodial activities of all compounds were evaluated. The known compounds labdan-13( E)-en-8α-ol-15-yl acetate (5), labdan-8α-ol-15-yl acetate (6), 13- epi-sclareol (7), labdan-13( E)-ene-8α,15-diol (8), and (8 R,13 S)-labdane-8α,15-diol (9) exhibited antiplasmodial effects, with IC50 values of 29.1, 33.2, 35.0, 36.6, and 22.2 μM, respectively.

Global trade increases plant introductions, but joint introduction of associated microbes is overlooked. We analyzed the ectomycorrhizal fungi of a Caribbean beach tree, seagrape (Coccoloba uvifera, Polygonacaeae), introduced pantropically to stabilize coastal soils and produce edible fruits. Seagrape displays a limited symbiont diversity in the Caribbean. In five regions of introduction (Brazil, Japan, Malaysia, Réunion and Senegal), molecular barcoding showed that seagrape mostly or exclusively associates with Scleroderma species (Basidiomycota) that were hitherto only known from Caribbean seagrape stands. An unknown Scleroderma species dominates in Brazil, Japan and Malaysia, while Scleroderma bermudense exclusively occurs in Réunion and Senegal. Population genetics analysis of S. bermudense did not detect any demographic bottleneck associated with a possible founder effect, but fungal populations from regions where seagrape is introduced are little differentiated from the Caribb...

The genus Psiadia Jacq. ex. Willd. belongs to the Asteraceae family and includes more than 60 species. This genus grows in tropical and subtropical regions, being especially well represented in Madagascar and the Mascarene Islands (La Réunion, Mauritius and Rodrigues). Several Psiadia species have been used traditionally for their medicinal properties in Africa and the Mascarene Islands. Based on traditional knowledge, various phytochemical and pharmacological studies have been conducted. However there are no recent papers that provide an overview of the medicinal potential of Psiadia species. Therefore, the aim of this review is to provide a comprehensive summary of the botany, phytochemistry and pharmacology of Psiadia and to highlight the gaps in our knowledge for future research opportunities. The available information on traditional uses, phytochemistry and biological activities of the genus Psiadia was collected from scientific databases through a search using the keyword 'Psiadia' in 'Google Scholar', 'Pubmed', 'Sciencedirect', 'SpringerLink', 'Web of Science', 'Wiley' and 'Scifinder'. Additionally, published books and unpublished Ph.D. and MSc. dissertations were consulted for botanical information and chemical composition. Historically, species of the genus Psiadia have been used to treat a wide range of ailments including abdominal pains, colds, fevers, bronchitis, asthma, rheumatoid arthritis, skin infections and liver disorders among others. Phytochemical works led to the isolation of flavonoids, phenylpropanoids, coumarins and terpenoids. Furthermore, phytochemical compositions of the essential oils of some species have been evaluated. Crude extracts, essential oils and isolated molecules showed in vitro pharmacological activities, such as antimicrobial, anti-viral, anti-inflammatory, antiplasmodial and antileishmanial activities. Crude extracts of Psiadia dentata and Psiadia arguta have specifically been found to be potentially useful for inhibition of growth of Plasmodium falciparum. However, pharmacological data on this particular genus is quite limited. Further research is necessary to determine the active compounds and the underlying mechanisms.

Vanilla planifolia embryogenic calli were cultured for two years on a medium containing thidiazuron (TDZ). Due to the presence of TDZ, these calli were under permanent chemical treatment and the differentiation of adventitious shoots from protocorm-like-bodies (PLBs) was blocked. When embryogenic calli were transferred onto a medium without TDZ, shoot organogenesis and plantlet regeneration occurred. To gain better knowledge about the biochemical and molecular processes involved in the morphoregulatory role of TDZ, hormonal and metabolomic analyses were performed. Our results indicate that in the presence of TDZ, embryogenic calli contained a high amount of abscisic acid (ABA) essentially metabolized into abscisic acid glucosyl ester (ABAGE) and phaseic acid (PA), which was the most abundant. When transferred onto a medium without TDZ, shoot regeneration and development take place in four stages that include: embryogenic calli growth, differentiation of PLBs from meristmatic cells zones (MCZ), shoot organogenesis from PLBs and the elongation of well-formed shoots. From a hormonal perspective, the significant reduction in ABA metabolism and its readjustment in the ABAGE pathway triggered PLBs formation. However, this first morphogenesis was stimulated by a strong reduction in IAA metabolism. The organogenesis of PLBs into shoots is associated with an increase in ABA catabolism and a gradual shift in cellular metabolism towards shoot differentiation. Thus, the initiation of the elongation process in shoots is correlated with an alteration in metabolite composition, including an increase in energy reserves (sucrose/starch) and a rapid decrease in alanine content. Our data highlighted the relationship between endogenous hormone signalling, carbohydrate metabolism and shoot organogenesis in Orchid plants.

The objective of the work was to characterize fungal endophytes from aerial parts of Vanilla planifolia. Also, to establish their biotransformation abilities of flavor-related metabolites. This was done in order to find a potential role of endophytes on vanilla flavors. Twenty three MOTUs were obtained, representing 6 fungal classes. Fungi from green pods were cultured on mature green pod based media for 30 days followed by (1)H NMR and HPLC-DAD analysis. All fungi from pods consumed metabolized vanilla flavor phenolics. Though Fusarium proliferatum was recovered more often (37.6 % of the isolates), it is Pestalotiopsis microspora (3.0 %) that increased the absolute amounts (quantified by (1)H NMR in μmol/g DW green pods) of vanillin (37.0 × 10(-3)), vanillyl alcohol (100.0 × 10(-3)), vanillic acid (9.2 × 10(-3)) and p-hydroxybenzoic acid (87.9 × 10(-3)) by significant amounts. All plants studied contained endophytic fungi and the isolation of the endophytes was conducted from plant...

Bacterial wilt, caused by Ralstonia solanacearum, is one of the most devastating plant diseases, affecting some economically important Solanaceae crops. In contrast, Solanum torvum, also known as wild eggplant, does not wilt when infested with R. solanacearum. In order to describe the mechanism underlying the response of S. torvum, it was compared with the cultivated eggplant, S. melongena, when both were infected with the same R. solanacearum strain. No wilting occurred in S. torvum, although the bacteria colonised roots and stems in both species within the first 24 h. There were marked differences beyond 24 h, consisting of high bacterial mortality in S. torvum. Using the calli model, our investigations revealed an increase in cell wall monoamine oxidase activity in S. torvum after R. solanacearum inoculation, which did not occur in S. melongena.

Sugarcane yellow leaf virus (SCYLV) was first detected in sugarcane of Réunion Island in 1997. A field experiment was undertaken to assess the potential impact of this virus on sugarcane production. The agronomic characteristics of SCYLV-infected plants were compared to those of virus-free plants of three sugarcane cultivars (R570, R577 and R579) which occupy more than 90% of the cultivated