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 ▲]

Screening Elisa method to assess in vitro efficacy of new agents based on Lactoperoxydase system against phytopathogens

Poster (2011, May 24)

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of ... [more ▼]

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of hydrogen peroxide in hypoiodite (OI-) and hypothiocyanite (OSCN-) ions. Both ions have inhibitory action against pathogenic bacteria, fungi and viruses. Until now, the ions OI- and OSCN- applied separately from the LPS were not tested against plant pathogens. Seventeen KI/KSCN/H2O2 ratios with 3 dilutions for each one were tested against Botrytiscinerea. Results showed that the ions OI- and OSCN- gives a better % of inhibition with: -high concentration of KI+KSCN, -a ratio of KI/KSCN of 4.5 and -a ratioof (KI+KSCN)/H2O2 near 1. Increased dilution combined with lower KI+KSCN concentration reduced the efficacy of the ions. From the screening against B.cinerea, 4 ratios of KI+KSCN were selected and tested against 6 other phytopathogens. Results showed that the OI- and OSCN- ions give 87 and 100% inhibition against Penicillium expansum and Verticillium dahlia respectively. The inhibitory activity of the ions solution was ranged between 70 and 79% regarding Fusarium avenaceum, Phytophthora infestans and Colletotrichum lindemuthanium. The ions OI- and OSCN- showed an insufficient inhibitory activity against Septoria tritici. The screening method highlighted that high KI/KSCN ratios and low dilution were more efficient against phytopathogens. The efficient ratios will be further evaluated in vivo. [less ▲]

Novel Application of the Lactoperoxydase system against postharvest diseases of the apple

Poster (2011, May)

Development of a Quick Quantitative Real-Time PCR for the In Vivo Detection and Quantification of Peach latent mosaic viroid

in Plant Disease (2011), 95(2), 137-142

Viroids are plant pathogens infecting a broad range of herbaceous and tree crops. Among them, the Peach latent mosaic viroid (PLMVd) infects mainly peach trees, causing a loss of production with no ... [more ▼]

Viroids are plant pathogens infecting a broad range of herbaceous and tree crops. Among them, the Peach latent mosaic viroid (PLMVd) infects mainly peach trees, causing a loss of production with no curative options. Detecting this viroid is thus important for certification procedures aiming to avoid the release of infected material into orchards. Presented here is a complete detection method based on reverse transcription (RT) followed by a quantitative real-time polymerase chain reaction (PCR). New primers were selected and optimal reaction conditions determined for routine application of the method. The technique is 105 times more sensitive than the endpoint RT-PCR used for PLMVd detection, and permits earlier detection of PLMVd in infected plants. The quick, low-cost extraction procedure used and the quality of the results obtained make this method suitable for routine testing. [less ▲]

Predictive modelling of the combined effect of temperature and water activity (aw) on the in vitro growth of Erwinia spp infecting potato tubers in Belgium

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(3), 378-386

Phenotypic evaluation of interspecific recombinant inbred lines (RILs) of Phaseolus species for their resistance to aluminum and tolerance to aluminum-toxic acid soil under greenhouse conditions

in Euphytica : International Journal of Plant Breeding (2011)

Aluminium (Al) toxicity limits common bean productivity in acid soil regions of the tropics. To improve Al resistance of common bean, Al-sensitive Phaseolus vulgaris (SER16) was crossed to Alresistant P ... [more ▼]

Aluminium (Al) toxicity limits common bean productivity in acid soil regions of the tropics. To improve Al resistance of common bean, Al-sensitive Phaseolus vulgaris (SER16) was crossed to Alresistant P. coccineus (G35346-3Q) to create 94 F5:6 recombinant inbred lines (RILs) of the pedigree SER16 9 (SER16 9 G35346-3Q). RILs were characterized for resistance to Al in a hydroponic system with 0 and 20 lM Al in solution, and for shoot and root growth response to Al-toxic infertile acid soil in 75 cm long soil cylinder system using an oxisol of low Al- (12.5%; pH 4.6; fertilized) and high Al-saturation (77%; pH 4.1; unfertilized). G35346-3Q increased its taproot elongation rate by 3.5% between 24 and 48 h under 20 lM Al in solution, while the best RIL, Andean genotype ICA Quimbaya, and sensitive genotype VAX1 expressed reductions of 2.6, 12.5, and 69.5%, respectively. In the acid soil treatment the correlation between leaf area and total root length was highly significant under high Al saturation (r = 0.70***). Genotypes that were Al resistant in the hydroponic system were not necessarily tolerant to Al-toxic acid soil conditions based on shoot and root growth responses. Phenotypic evaluation using both systems allows the identification of genotypes with Al resistance combined with acid soil adaptation. Two genotypes (ALB88 and ALB91) emerged as lines with multiple traits. Results suggest that inheritance of Al resistance and acid soil tolerance in G35346-3Q is complex. Results from this work will be useful for identification of molecular markers for Al resistance in Phaseolus species and to improve acid soil adaptation in common bean. [less ▲]

Evaluation of three essential oils as potential source of botanical fungicide

Conference (2010)

Pre-indexing Musa accessions and sanitation of the infected ones

Report (2010)

A Simple And Rapid Protocol Of Crude Dna Extraction From Apple Trees For Pcr And Real-Time Pcr Detection Of 'Candidatus Phytoplasma Mali'

in Journal of Virological Methods (2009), 156(1-2), 96-101

Pre-indexing Musa accessions and sanitation of the infected ones

Report (2009)