Implication of microRNAs in the response of Brachypodium distachyon (L.) Beauv. root system architecture to rhizobacterial volatiles

Scientific conference (2013, February)

The metabolic roles of volatile organic compounds (VOCs) emitted by plant growth-promoting rhizobacteria (PGPR) and the identity of the molecules responsible for the growth promotion are still poorly ... [more ▼]

The metabolic roles of volatile organic compounds (VOCs) emitted by plant growth-promoting rhizobacteria (PGPR) and the identity of the molecules responsible for the growth promotion are still poorly documented. As well, the implication of microRNAs in root development is a recent discovery that deserves to be explored. In this study, the implication of microRNAs in the response of Brachypodium distachyon (L.) Beauv. Bd21 root architecture to rhizobacterial VOCs was investigated. Nineteen PGPR strains were screened to select those showing the strongest phenotypic effects. The strain Bacillus subtilis AP305-GB03 induced the most important promotion of biomass production and root development. Total RNA extraction and RT-qPCR analysis of microRNAs were performed on Bd21 root samples. The expression of miR160 a-d, miR164 f, miR167 c-d, miR397 b and miR399 a-b was measured in roots every 2 days during the first 10 days of Bd21 development, in the presence or absence of the bacterial VOCs. Differences in the expression profile of miR164 f and miR167 c-d were observed in the roots exposed to GB03 VOCs, as compared to the control. These differences could be correlated to the root system architecture modifications observed after 10 days of growth with GB03. miR397 b and miR399 a-b also showed differences in the expression profile of roots exposed to the bacterial VOCs. These microRNAs have been respectively involved in cold stress tolerance and in the response to phosphate starvation. [less ▲]

Improvement of Ylang-Ylang Essential Oil Characterization by GCxGC-TOFMS

in Molecules (2013), 18(2), 1783-1797

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography ... [more ▼]

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used to improve the chemical characterization of ylang-ylang essential oil fractions recently reported in a previous one-dimensional (1D) GC study. Based on both, the enhanced chromatographic separation and the mass spectral deconvolution, 161 individual compounds were identified and labeled as potentially characteristic analytes found in both low and high boiling fractions issued from distillation of mature ylang-ylang flowers. Compared to the most recent full GC-MS characterization, this represents 75 new compounds, essentially consisting of terpenes, terpenoid esters, and alcohols. [less ▲]

Comparative Chemical and Molecular Variability of Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Ylang-Ylang) in the Western Indian Ocean Islands: Implication for Valorization

in Chemistry & Biodiversity (2012), 9(7), 13891402

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite ... [more ▼]

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang-ylang grown in semi-managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang-ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations. [less ▲]

Improvement of Ylang-ylang essential oil characterization by GC×GC-TOFMS.

Poster (2012, February 02)

Variations in the essential oils from ylang-ylang (Cananga odorata [Lam.] Hook f. & Thomson forma genuina) in the Western Indian Ocean islands

in Flavour and Fragrance Journal (2012), 27(5), 356-366

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical ... [more ▼]

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical polymorphism of the different production areas. This underestimated variability is an interesting source of raw material for perfumers. That is why the variation in the chemical composition of four fractions of the essential oils extracted from Cananga odorata, grown in four locations Grande Comore, Mayotte, Nossi Bé and Ambanja, was studied. A total of 119 compounds, representing 85.7–96.4%of the total essential oil composition, were identified using gas chromatography–mass spectrometry and quantified by gas chromatography with a flame ionization detector. Thirty-two compounds previously unreported in ylang-ylang essential oil were identified. The distinction between the Comoros and Madagascar groups wasmade on the basis of the chemical classes. It was possible to significantly distinguish the Grande Comore and Mayotte essential oil samples, as well as the Ambanja and Nossi Bé essential oil samples, on the basis of their main compounds. The aromatic compounds profile for the origin of each essential oil fraction was established. Regression trees were built, allowing the provenance of the essential oils prepared at the laboratory level to be easily differentiated on the basis of a limited number of major compounds. [less ▲]

Scaphandre La science rencontre l'art: L'alimentation

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

Organ-dependent oxylipin signature in leaves and roots of salinized tomato plants (Solanum lycopersicum)

in Journal of Plant Physiology (2012), 169

Les volatils racinaires de l’orge: un langage souterrain entre plantes?

Poster (2011, October 13)

Rhizobacterial volatile organic compounds modulate biomass production and root architecture in Arabidopsis thaliana (L.) Heynh. and Brachypodium distachyon (L.) P. Beauv.

Conference (2011, October)

Volatile organic compounds of the roots of barley and their role in the rhizosphere

Poster (2011, May 24)

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates ... [more ▼]

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates. Very few researches have been completed concerning belowground volatiles released into the rhizosphere despite their potential capacity to carry information between organisms. The Rhizovol project, started in autumn 2010, involves 5 different units of Gembloux Agro-Bio Tech collectively studying the production of belowground volatiles by barley roots underlying various biotic interactions in the rhizosphere. Some preliminary results of each partner of the project will be presented. To achieve this goal, analytical methods allowing the sampling, separation, identification and quantification of belowground volatile compounds have to be developed, taking into account their potential modifications in the rhizosphere once released by the roots. They enable the subsequent characterization and study of the interactions between barley and its rhizospheric partners chosen for this study. These interactions imply three types of organisms: beneficial organisms, pathogenic agents and plant and insect pests. Beneficial organisms can promote the growth of barley by the emission of volatiles; on the other hand barley can support their growth and metabolism. These phenomenons will be assessed by the study of 19 strains of plant growth-promoting bacteria (PGPR). Three pathogenic agents - two fungi (Fusarium culmorum and Cochliobolus sativus) and one virus (Barley yellow dwarf virus) - were chosen as they are known to cause various diseases on barley, especially on roots. The attractive or repellent effects of barley root volatiles on the pathogenic agents or their vectors, as well as the effect of volatiles on the diseases evolution will be evaluated. The project also includes several types of pests such as plants and insects. Plants can compete with barley for space and nutrients through volatile interactions. This will be assessed by the study of autotoxicity by barley itself and allelopathy with 8 weeds and a hemiparasitic plant (Rhinanthus minor). The effects of barley volatiles can also impact the severity of the attacks by insects. This part will be conducted with wireworms as they represent worldwide known pests, and aphids, through their viral vector role. Eventually, as soil characteristics can strongly influence the diffusion of volatile compounds, the diffusion behaviour of the identified volatile biomolecules through the soil will be modelled. Tritrophic interactions (e.g. insect-plant-pathogenic fungi) will be studied based on each bitrophic interaction results. Over-all, the Rhizovol project aims at improving the knowledge of interactions mediated by volatile compounds in the rhizosphere and at establishing new biocontrol methods that could contribute to integrated disease and pest management systems. [less ▲]