Mohsen Hanana

Chemical composition, phytotoxic and antifungal activities of Pinus pinea essential oil

The chemical composition of essential oils isolated by hydrodistillation from the aerial parts of Tunisian Pinus pinea Linn. was analyzed by GC and GC/MS. Sixty-six compounds were identified, representing 98.5% of total oil, which was found to be rich in monoterpene hydrocarbons (73.1%) particularly limonene (54.1%), α-pinene (7.7%), and β-pinene (3.4%). The yield and the physico-chemical properties were determined. Results of the antifungal activity study by in vitro contact assay showed that P. pinea oil significantly inhibited the growth of ten plant pathogenic fungi. Moreover, herbicidal properties of the oil, tested on Sinapis arvensis L., Lolium rigidum Gaud., and Raphanus raphanistrum L., indicated that the oil completely inhibited the seed germination at a high concentration, while at low doses the oil acted by decreasing and delaying the germination and inhibiting the seedling growth of all tested weeds unlike the commercial herbicide. Our results showed that P. pinea essential oil could be valorized as bioproduct for biocontrol of weeds and fungal plant diseases.

Copper Transport and Compartmentation in Grape Cells

Copper-based fungicides have been widely used against several grapevine (Vitis vinifera L.) diseases since the late 1800s when the Bordeaux mixture was developed, but their intensive use has raised phytotoxicity concerns. In this study, physiological, biochemical and molecular approaches were combined to investigate the impacts of copper in grape cells and how it is transported and compartmented intracellularly. Copper reduced the growth and viability of grape cells (CSB, Cabernet Sauvignon Berry) in a dose-dependent manner above 100 µM and was accumulated in specific metal ion sinks. The copper-sensitive probe Phen Green SK was used to characterize copper transport across the plasma membrane of CSB cells. The transport system (K(m) = 583 µM; V(max) = 177 × 10(-6) %ΔF min(-1) protoplast(-1)) was regulated by copper availability in the culture medium, stimulated by Ca(2+) and inhibited by Zn(2+). The pH-sensitive fluorescent probe ACMA (9-amino-6-chloro-2-methoxyacridine) was used to evaluate the involvement of proton-dependent copper transport across the tonoplast. Cu(2+) compartmentation in the vacuole was dependent on the transmembrane pH gradient generated by both V-H(+)-ATPase and V-H(+)-pyrophosphatase (PPase). High copper levels in the growth medium did not affect the activity of V-H(+)-PPase but decreased the magnitude of the H(+) gradient generated by V-H(+)-ATPase. Expression studies of VvCTr genes showed that VvCTr1 and VvCTr8 were distinctly affected by CuSO(4) availability in grape cell cultures and that both genes were highly expressed in the green stage of grape berries.

Identification et caractérisation d'un gène de réponse à la déshydratation « rd22 » chez la vigne (Vitis vinifera L.)

To identify and isolate genes related to abiotic stresses (salinity and drought) tolerance in grapevine, a candidate gene approach was developed and allowed isolating a full-length cDNA of rd22 gene from the Cabernet Sauvignon variety. The latter, named Vvrd22, is a dehydration-responsive gene that is usually induced by the application of exogenous ABA. Details of the physicochemical parameters and structural properties (molecular mass, secondary structure, conserved domains and motives, putative post-translational modification sites...) of the encoded protein have also been elucidated. The expression study of Vvrd22 was carried out at the berry growth stages and at the level of plant organs and tissues as well as under both drought and salt stresses. The results showed that Vvrd22 is constitutively expressed at a low level in all analyzed tissues. Moreover, salt stress induced Vvrd22 expression, particularly for the tolerant variety (Razegui), contrary to the sensitive one (Syrah), which did not display any expression variation during the stress, which means that Vvrd22 is involved in salt stress response and that its expression level depends on regulatory mechanisms that are efficient only for the tolerant variety. On the other hand, under drought stress, Vvrd22 is induced in an identical manner for both tolerant and sensitive varieties. In addition, stress signal molecules such as ABA (lonely applied or in combination with sucrose) induced Vvrd22 expression, even at a low level. A minimal knowledge about the role and the functionality of this gene is necessary and constitutes a prerequisite condition before starting and including Vvrd22 in any program of improvement of grapevines abiotic stress tolerance.

Copper homeostasis in grapevine: functional characterization of the Vitis vinifera copper transporter 1

Main conclusionTheVitis viniferacopper transporter 1 is capable of self-interaction and mediates intracellular copper transport.AbstractAn understanding of copper homeostasis in grapevine (Vitis vinifera L.) is particularly relevant to viticulture in which copper-based fungicides are intensively used. In the present study, the Vitis vinifera copper transporter 1 (VvCTr1), belonging to the Ctr family of copper transporters, was cloned and functionally characterized. Amino acid sequence analysis showed that VvCTr1 monomers are small peptides composed of 148 amino acids with 3 transmembrane domains and several amino acid residues typical of Ctr transporters. Bimolecular fluorescence complementation (BiFC) demonstrated that Ctr monomers are self-interacting and subcellular localization studies revealed that VvCTr1 is mobilized via the trans-Golgi network, through the pre-vacuolar compartment and located to the vacuolar membrane. The heterologous expression of VvCTr1 in a yeast strain lacking all Ctr transporters fully rescued the phenotype, while a deficient complementation was observed in a strain lacking only plasma membrane-bound Ctrs. Given the common subcellular localization of VvCTr1 and AtCOPT5 and the highest amino acid sequence similarity in comparison to the remaining AtCOPT proteins, Arabidopsis copt5 plants were stably transformed with VvCTr1. The impairment in root growth observed in copt5 seedlings in copper-deficient conditions was fully rescued by VvCTr1, further supporting its involvement in intracellular copper transport. Expression studies in V. vinifera showed that VvCTr1 is mostly expressed in the root system, but transcripts were also present in leaves and stems. The functional characterization of VvCTr-mediated copper transport provides the first step towards understanding the physiological and molecular responses of grapevines to copper-based fungicides.

Chemical composition, physico-chemical properties, antifungal and herbicidal activities of Pinus halepensis Miller essential oils

The chemical composition, physico-chemical properties, and antifungal and herbicidal activities of essential oils obtained by hydrodistillation from needles, stems and cones of Pinus halepensis Miller were investigated. The chemical composition analysed by GC and GC/MS varied significantly among organs. Among the 67 identified components, α-pinene (63% and 51.7%, respectively, in stems and cones) and (Z)-caryophyllene (33.9% in needles) were found to be the major ones. Moreover, it was found that chemical composition of essential oils extracted from different organs of P. halepensis Miller growing in Tunisia showed noteworthy differences with the same species cultivated in Algeria, Morocco, Greece and Italy based on a comparison with published results. In addition, the physico-chemical properties of essential oils from different organs of P. halepensis were analysed. The analysis of the refraction index, density and acid index of different oil samples showed a weak variability among organs. The in vitro antifungal activity of the essential oil samples evaluated against 10 cultivated crop fungi was found to be low, probably due to the low level of oxygenated compounds in P. halepensis oils. In contrast, the herbicidal activity investigated towards three common weeds in Tunisian cereal crops was very strong and seed germination was inhibited at 2 μl ml− 1. Thus, P. halepensis essential oil appears to have more value as a bioherbicide than as a biofungicide.

Comparative study of two coniferous species (Pinus pinaster Aiton and Cupressus sempervirens L. var. dupreziana [A. Camus] Silba) essential oils: chemical composition and biological activity

Maritime pine ( Pinus pinaster Aiton) and Saharan cypress ( Cupressus sempervirens L. var. dupreziana [A. Camus] Silba) are two cone-bearing seed coniferous woody plants. The chemical composition of their essential oils, isolated from needles and leaves by hydrodistillation, was analyzed with gas chromatography (GC) and gas chromatography mass spectrometry (GC/MS). A total of 66 and 28 compounds were identified, which represented 99.5% and 98.9% of total pine and cypress oils, respectively. Pinus pinaster oil was found to be rich in α-pinene (31.4%), (Z)-caryophyllene (28%), and α-humulene (6.7%); it was characterized by relatively high amounts of monoterpene and sesquiterpene hydrocarbons (44.5% and 46.3%, respectively). The major components identified in cypress oil were manoyl oxide (34.7%), α-pinene (31.8%), α-humulene (9%), and 6-3-carene (8.7%). Results of in vitro antifungal test assays showed that both oils significantly inhibit the growth of 10 plant pathogenic fungi. Herbicidal effects of the oils on seed germination, seed vigor, and seedling growth of three common crop weeds Sinapis arvensis L., Phalaris paradoxa L., and Raphanus raphanistrum L. were also determined; the oils completely inhibited seed germination and seedling growth of all the weeds.

Essential oil composition, phytotoxic and antifungal activities of Ruta chalepensis L. leaves from High Atlas Mountains (Morocco)

This study aimed at the determination of chemical composition of essential oil obtained by hydrodistillation, and to evaluate their phytotoxic and antifungal activities. Leaves of Ruta chalepensis L. were collected from the region of Tensift Al Haouz (High Atlas Mountains) Marrakech, Morocco. The essential oil (oil yield is 0.56%) was analysed by GC-FID and GC/MS. Twenty-two compounds were identified and accounted for 92.4% of the total oil composition. The major components were undecan-2-one (49.08%), nonan-2-one (33.15%), limonene (4.19%) and decanone (2.71%). Antifungal ability of essential oils was tested by disc agar diffusion against five plant pathogenic fungi: Fusarium proliferatum, Fusarium pseudograminearum, Fusarium culmorum, Fusarium graminearum and Fusarium polyphialidicum. The oils were also tested in vitro for herbicidal activity by determining their influence on the germination and the shoot and root growth of two weed species, Triticum durum and Phalaris canariensis L.

Chemical composition, phytotoxic and antifungal properties of Ruta chalepensis L. essential oils.

The chemical composition, and phytotoxic and antifungal activities of the essential oils isolated by using hydrodistillation from the aerial parts of Tunisian rue were evaluated. Significant variations were observed among harvest periods. The analysis of the chemical composition by gas chromatography/mass spectrometry showed that 2-undecanone (33.4–49.8%), 2-heptanol acetate (13.5–15.4%) and α-pinene (9.8–11.9%) were the main components. The antifungal ability of rue essential oils was tested by using disc agar diffusion against ten plant pathogenic fungi. A high antifungal activity was observed for the essential oil isolated at flowering developmental phase. Furthermore, rue essential oils showed high level of herbicidal activity against several weeds.

Allelopathic effects of essential oils of Pinus halepensis Miller: chemical composition and study of their antifungal and herbicidal activities

The chemical composition, phytotoxic and antifungal activities of the essential oils isolated by hydrodistillation from the needles of Tunisian Aleppo pine harvested from different provenances were evaluated. The chemical composition analysed by gas chromatography/mass spectrometry (GC/MS) revealed variability among provenances displaying interesting chemotypes, (Z)-caryophyllene (16.16–28.9%), β-myrcene (8.5–22.9%), α-pinene (11.7–13.14%), β-pinene (3.13–11.8%), bicyclogermacrene (5.2–12.37%), α-terpinolene (8.11–11.01%) and α-humulene (2.85–5.2%), which were the main components in the oil. Antifungal ability of Aleppo pine oils was tested by disc agar diffusion against 10 phytopathogenic fungi. Weak antifungal activity was observed for the essential oils isolated. Furthermore, in contrast, the herbicidal activity investigated for three common weeds in Tunisian cereal crops was very strong and seed germination was inhibited at a low concentration and their herbicidal effects were higher than those of a commercial herbicide.

Propriétés antifongiques des huiles essentielles de Biota orientalis L.

RésuméLa composition chimique des huiles essentielles d’aiguilles et de cônes de Biota orientalis L. extraites par hydrodistillation a été analysée par chromatographie gazeuse associée à une détection à ionisation de flamme (CG-DIF) et par chromatographie gazeuse couplée à la spectrométrie de masse (CG-SM). Vingt et un composés ont été identifiés chez l’huile essentielle de Biota orientalis, qui s’est avérée particulièrement riche en monoterpènes hydrocarbonés. Des différences quantitatives principalement ont été observées entre les aiguilles et les cônes, quoiqu’ils affichent le même chémotype. Pour les deux huiles, α-pinène (67 et 47 % respectivement chez les cônes et les aiguilles), β-phellandrène (5,1 et 10,9 %) et α-cédrol (4,6 et 7,5 %) constituent les composés majeurs identifiés. L’étude de leur activité antifongique vis-à-vis d’une dizaine de champignons phytopathogènes a révélé des propriétés intéressantes qui pourraient être valorisées en tant que biofongicide.AbstractThe chemical composition of essential oils isolated by hydrodistillation from needles and cones of Biota orientalis L. was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Twenty one compounds were identified in Biota orientalis essential oil which appeared to be rich in monoterpene hydrocarbons. Quantitative differences mainly, between cone and needle oils, were observed, although they displayed the same chemotype. For both oils, α-pinene (67 and 47% respectively in cones and needles), β-phellandrene (5.1 and 10.9%) and α-cedrol (4.6 and 7.5%) were the major constituents. The study of their antifungal activity towards ten plants pathogenic fungi revealed interesting properties that could be applied as biofungicide.