First report of banana mild mosaic virus infecting plantain in Ivory Coast

in Plant Disease (in press)

Development of a test to assess the Banana Bunchy Top Virus transmissibility through direct analysis of its aphid vector Pentalonia nigronervosa

in Communications in Agricultural and Applied Biological Sciences (2013, February), 78(1), 49-54

The susceptibility of bananas to crown rot disease is influenced by geographical and seasonal effects

in Canadian Journal of Plant Pathology = Revue Canadienne de Phytopathologie (2013)

Crown rot of banana fruits is caused by a complex of fungal pathogens, the most common of which is Colletotrichum musae, and is one of the main quality defects of exported bananas. Susceptibility of ... [more ▼]

Crown rot of banana fruits is caused by a complex of fungal pathogens, the most common of which is Colletotrichum musae, and is one of the main quality defects of exported bananas. Susceptibility of banana fruits to crown rot is influenced by many pre-harvest factors. The aim of this study was to improve on the methodology for the evaluation of fruit susceptibility and to verify whether cultivation areas in Cameroon as well as seasonal variations have an influence on the susceptibility to crown rot. Fruit susceptibility was evaluated on a monthly basis throughout a year (including the dry and rainy seasons) in three banana plantations located at very different agro-ecological conditions (two in a lowland area and one in a highland area). Fruit susceptibility was determined through an internal necrotic surface (INS) assessment after artificial inoculation with C. musae. The standardization of post-inoculation environmental conditions enabled more reliable INS assessments. Fruit susceptibility was found to be significantly influenced by cultivation area (P<0.001) since fruits grown in low altitude (Dia-dia, Koumba, 80 m) were more susceptible than fruits grown in high altitude (Ekona, 500 m). Although no seasonal effect was observed (P=0.075), there was a highly significant date effect (P<0.001). This was specifically the case in low altitude plantations where fruit susceptibility was higher for some harvest dates within the rainy season. In Ekona, fruit grade and number of leaves on the banana plant were found to be significantly higher than in the two other locations, while black leaf streak disease severity was significantly lower. The potential relationship with fruit susceptibility is fully discussed. [less ▲]

Banana macropropagation: an alternative way of producing seedlings for the farmers in Burundi

Poster (2012, May 22)

Effect of a fungal infection on the spectrum of volatile organic compounds emitted by plant roots

Conference (2012, May 22)

Development and application of a microplate method to evaluate the efficacy of essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens of fruits

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 325-336

A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two ... [more ▼]

A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two 96-well ELISA plates was used as a reproducible and standardized design to identify the in vitro effectiveness of these essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens, on fruits. Growth of mycelium was monitored by measuring optical density (492 nm). Cinnamomum zeylanicum, Cinnamomum verum and Eugenia caryophyllus were found to be still active against all the three pathogens even at 100 ppm. Compared to other methods, this microbioassay proved to be a rapid, reproducible, and efficient method for testing the efficacy of essential oils that inhibit spore germination in P. italicum, P. digitatum and C. musea. The assay requires relatively small amounts of essential oils. [less ▲]

cDNA-AFLP analysis of gene expression changes in apple trees induced by phytoplasma infection during compatible interaction

in European Journal of Plant Pathology (2012), 134

Abstract In order to gain insight into molecular and physiological changes in apple trees during compatible interaction with two ‘Candidatus Phytoplasma mali’ strains (AP and AT), cDNA-Amplified Fragment ... [more ▼]

Abstract In order to gain insight into molecular and physiological changes in apple trees during compatible interaction with two ‘Candidatus Phytoplasma mali’ strains (AP and AT), cDNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) technique was used. A rootstock of apple (MM106) susceptible to ‘Ca. P. mali’ was used to extend the range of the potential host responses by the maximum number of identified genes that will be deregulated by phytoplasma in apple. Gene expression comparisons were studied in three directions: healthy versus infected samples, symptomatic versus nonsymptomatic sample, and AP-infected versus ATinfected sample. Forty-five genes whose steady-state levels of expression significantly changed in response to phytoplasma infection were identified. Among their partial cDNA sequences, only 27 showed similarity to DNA or protein data bases; of these, 18 were related to known genes in plants, and the rest were related to unknown or hypothetical proteins. Eighteen out of 45 did not show any similarity with sequences in data bases (potential novel genes). Quantitative real-time RT-PCR (qRT-PCR) was used to confirm differential expression of AFLP identified genes, and showed the similar profile expression for 11 known genes among 18, and for 13 unknown, hypothetical or novel genes among 27. Changes in gene expression involved a wide spectrum of biological functions, including processes of metabolism, cell defence, senescence, photosynthesis, transport, transcription, signal transduction and protein synthesis. This is the first study of global gene profiling in plants in response to phytoplasma infections using cDNA-AFLP, and a model is proposed to explain the mode of action of the ‘Ca. P. mali’ in apple. [less ▲]

Models to predict the combined effects of temperature and relative humidity on Pectobacterium Atrosepticum and Pectobacterium carotovorum subsp. Carotovorum population density and soft rot disease development at the surface of wounded potato tubers

in Journal of Plant Pathology [=JPP] (2012), 94(1), 181-191

The main objectives of this study were to evaluate and model the influence of temperature (10, 15 and 20°C), relative humidity (86, 96 and 100%) and initial concentration of bacterial inoculum (105, 107 ... [more ▼]

The main objectives of this study were to evaluate and model the influence of temperature (10, 15 and 20°C), relative humidity (86, 96 and 100%) and initial concentration of bacterial inoculum (105, 107 et 109 CFU ml-1) on the population density of Pectobacterium atrosepticum (Pba) and Pectobacterium carotovorum subsp. carotovorum (Pcc) which are important potato pathogens in temperate climates, and on the development of soft rot symptoms caused by these bacteria at the surface of wounded potatoes tubers under controlled conditions. Experiments were carried out according to a Box-Behnken experimental design, simplifying prediction of the combined effects of three controlled factors. With both bacterial species, statistical analysis showed a significant effect of temperature, relative humidity and initially applied bacterial concentration on population dynamics and soft rot development at the surface of wounded potato tubers. Multiple regression analyses and the contour plots showed that the temperature is the most important factor, followed by the initially applied bacteria concentration and relative humidity. More than 64% of the variability of the soft rot symptoms observed could be explained by the presence of Pba and Pcc at the level of wounded potato tubers under the combined effect of tested factors. The quadratic polynomial models developed in our research should integrate the heterogeneity of tested bacteria belonging to the same species (which was not evaluated in this preliminary investigation) in further research. [less ▲]

Interactions volatiles entre les racines d’orge et quelques agents pathogènes

Poster (2011, October 13)

Biocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple.

Conference (2011, August 31)

Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala ... [more ▼]

Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A molecular study revealed implication of exo-β-1,3-glucanases in the mode of action of P. anomala but suggested implication of other factors. The present study aims to increase our knowledge of the mode of action of P. anomala strain Kh6 against B. cinerea using an in situ approach allowing interactions between organisms, and the proteomic tool allowing to study the ultime expression of the genome. One wound per apple were covered by a membrane and inoculated by P. anomala then by B. cinerea or not. Samples were collected at different incubation times to identify the responses of P. anomala to the presence of B. cinerea. After extraction, proteins were separated on 2-D gels. Spots influenced were identified by MALDI-ToF. In exponential phase, P. anomala Kh6 orientates its energetic metabolism from the glycolysis to the oxidative phosphorylation and sets up the pentose phosphate pathway. Thanks to this new pathway, P. anomala probably obtains energy and nucleic acids allowing to colonize the wound as fast as in absence of B. cinerea. In stationary phase, no differences in the P. anomala energetic metabolism, in absence and in presence of B. cinerea were observed. During that phase, P. anomala seems to use the alcoholic fermentation in order to face the nutrients impoverishment of the substrate. [less ▲]