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In the present study, eight single-spore strains of Botrytis cinerea were isolated from tomato greenhouses located in Bejaia regions (Northern Algeria). Isolates were molecularly characterized by nine microsatellite markers. Isolates were assigned to B. cinerea and B. pseudocinerea with four isolates of each species. Morphological characterization was established using two cultures media Potato Dextrose Agar and Malt Extract Agar. All isolates inoculated on PDA medium were exclusively Sclerotial and Mycelial on MEA medium. Aggressiveness of both species was similar on tomato leaves and apple fruits. Moreover, B. cinerea isolates were more aggressive than B. pseudocinerea on lettuce leaves. Tomato and lettuce leaves were significantly more susceptible to the both fungi. A negative correlation was established between aggressiveness and morphological type. Phenotypic variability is considered of major importance to explain the epidemiology of the two cryptic species.

Bacteria endophytes are living microorganisms that live inside plant tissues without visible harmful symptoms, providing a mutualistic interaction. In this study, different bacterial endophytic strains were isolated from different plants primed to live in an arid area, namely, the Sahara Desert. Up to 27 of these strains were selected based on their ability to inhibit Botrytis cinerea growth in dual-culture assay and by bacterial volatiles. The results presented in this study show the capacity of most of the bacterial strains to protect Solanum lycopersicum against the pathogenic fungus B. cinerea, under different experimental conditions. Five of these strains induced susceptibility in tomato plants and no callose accumulation upon fungal infection, pointing to callose deposition as a protective mechanism mediated by endophytic bacteria. Moreover, there was a significant correlation between the bacterial strains inducing callose and the level of protection against B. cinerea. On the other hand, hormone production by bacteria does not explain the relationship between protection and the differences between the phenotypic results obtained in vitro and those obtained in plant experiments. Induced resistance is highly specific in the inducer-plant-stress interaction.

Bacteria endophytes are living microorganisms that live inside plant tissues without visible harmful symptoms, providing a mutualistic interaction. In this study, different bacterial endophytic strains were isolated from different plants primed to live in an arid area, namely, the Sahara Desert. Up to 27 of these strains were selected based on their ability to inhibit Botrytis cinerea growth in dual-culture assay and by bacterial volatiles. The results presented in this study show the capacity of most of the bacterial strains to protect Solanum lycopersicum against the pathogenic fungus B. cinerea, under different experimental conditions. Five of these strains induced susceptibility in tomato plants and no callose accumulation upon fungal infection, pointing to callose deposition as a protective mechanism mediated by endophytic bacteria. Moreover, there was a significant correlation between the bacterial strains inducing callose and the level of protection against B. cinerea. On the other hand, hormone production by bacteria does not explain the relationship between protection and the differences between the phenotypic results obtained in vitro and those obtained in plant experiments. Induced resistance is highly specific in the inducer-plant-stress interaction.

Poster présenté au 15. IOBC-WPRS meeting of the working group "Biocontrol products: From lab testing to product development", Lleida, ESP (2018/04/23-26) https://prodinra.inra.fr/record/434756; International audience; The strain Pseudomonas helmanticensis CT22 isolated from tomato stem in a tomato greenhouse in Bejaia (Algeria) has shown a good protective efficacy against Botrytis cinerea in controlled conditions but its effect against various strains of B. cinerea was not assessed. In this study, we evaluated the diversity in the sensitivity of sixty two strains of B. cinerea strains to P. helmanticensis CT22 both in vitro and on tomato. In vitro effect of the biocontrol agent is variable according to the strain of B. cinerea, both in dual culture assay or in volatile assay. Due to the very high level of efficacy against all tested strains of B. cinerea on detached tomato stem when P. helmanticensis CT22 was applied at 107 CFU/ml, the dose of application was reduced 10-fold at 106 CFU/ml. In this condition, the protective efficacy of the biocontrol agent is significantly influenced by B. cinerea strains with protection levels ranging from 24% to 100%. These results suggest a diversity in the sensibility of the different strains of B. cinerea to the biological control agent and emphasize the importance to consider several strains of a given plant pathogen species when screening a biocontrol agent.

45 bacterial isolates from potatoes and wheat rhizospheres near Setif (Algeria) pre-selected for their antagonistic activity against three fungal plant pathogens, two necrotrophic Fusarium solani var. coeruleum and Phytophtora infestans, and a systemic F. oxysporum f. sp. albedinis. Molecular typing of the isolates showed abundance of Bacillus compared to Pseudomonas. Some of the tested strains have shown very high biofilm formation. Among the 24 Gram-positive bacilli screened for four cyclic lipopeptides genes, some isolates harbor two or more genes, while others have a single gene or have none. Four selected isolates were able to regulate the expression of six defense-related genes in Arabidopsis and produce salicylic acid. Upon the features assessed in this study, strain B. amyloliquefaciens A16 was selected for a subsequent use as seed treatment and biocontrol agent in semi-arid region fields. This strain showed important biofilm formation, regulation of Arabidopsis defenses, and harbored three cLPs genes.

International audience; In order to find biocontrol agents that are both efficient against Botrytis cinerea Pers. and adapted to tomato growing conditions in Algeria, 121 bacterial strains were collected from tomato plants and nearby soils in two Bejaia greenhouses. A total of 37 strains were selected based on their ability to grow on agar medium and on their different level of B. cinerea mycelial growth inhibition in dual-culture tests. These strains were identified at the species level and those that corresponded to potential pathogens for humans or mammals were discarded. Among the remaining 25 candidates, three strains were selected among the Pseudomonas genus for their significant protective efficacy against B. cinerea on tomato, their ability to grow at 15–25 °C and their inability to grow at 37 °C. These three strains significantly reduced the development of necrotic lesion and the sporulation of B. cinerea in a dose-dependent manner. This study constitutes a first step towards the biological control of B. cinerea in tomato greenhouses in Algeria.

Two samples of essential oils from the leaves and cones of wild Tetraclinis articulata (Vahl.) Masters from two different sites in Algeria were isolated by hydrodistillation and investigated by gas chromatography (GC) and GC/mass spectrometry (GC/MS). A total of forty compounds were identified representing 98.6–99.8% of the oils. The main components of the volatile oils were α-pinene (19.8–24.9%) and bornyl acetate (40.2–59.2%) for the leaves, α-pinene (57.5–75%), limonene (10.6–20.9%) and β-myrcene (3.6–10.6%) for the cones. The antioxidant efficiency was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging method. In comparison with butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), which were used as positive controls, all samples showed weak activity. The antimicrobial activities of the essential oils were assayed by using the disc diffusion method and agar dilution technique on Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus...

Improving transportation efficiency without increasing urban traffic congestion, requires to carry out new services such as ridesharing which contributes to reduce operating cost and to save road resources. In this paper, we provide users of a ridesharing system greater flexibility: given a set of drivers’ offers already in the system, and a new rider’s request, we determine a best driver, a best pick-up and drop-off locations, and a sharing cost rate between rider and driver for their common path. The main idea of our approaches consists in labelling interesting nodes of a geographical map with information about drivers, in so-called buckets. Based on the information contained in these buckets, when a rider enters the system we determine a best driver, as well as a best pick-up and drop-off locations that minimize the total travel cost of rider and driver. Exact and heuristic approaches to identify a best driver, as well as a best pick-up and drop-off locations are proposed. Finally, we perform a comparative evaluation using real road network of the Lorraine region (FR) and real data provided by a local company. Experimental analysis shows a running time of a few seconds while improving participants’ cost-savings and matching rate compared to the recurring ridesharing.

In this work, we investigate the potential benefits of introducing relay stations in the round-trip ridesharing problem. In the classical round-trip ridesharing system, the pick-up and drop-off locations for the rider don’t differ from his origin and destination, respectively, for both outgoing and return trips. This system is straightforward but inflexible and unbalanced as it puts the whole detour effort on the driver’s shoulders. In this paper, we propose to consider a meeting location as flexible and to determine its optimal position minimizing total travel cost for the round-trip. The meeting locations correspond to relay stations in which riders find ridesharing vehicles. The introduction of relay stations in the round-trip ridesharing problem creates dependency between the outgoing and return trips, in the sense that the relay stations must be chosen in such a way as to minimize the combined travel cost of the outgoing and return trips. In this setting, the rider is supposed to drive to the relay station with his private car and to park it there, so the return trip has to drop him there to get his car back. We present efficient algorithms to solve this problem and, finally, we perform a comparative evaluation using a real road network and real dataset provided by a local company. Our numerical results show the effectiveness of our system, which improves participants’ cost-savings and matching rate compared to the classical round-trip ridesharing system.

We propose a new aspect of mobility that combines in a same journey and in real time a carpooling service and a traditional multi-modal transportation. This mix allows to improve and complete both services. The main idea of our approach is based on the traditional multi-modal path, in which we try to sequentially substitute some sub-paths of traditional multi-modal transportation to carpooling, in order to decrease the rider’s arrival time at his destination. For this purpose, we first define a closeness estimation between the user’s itinerary and available drivers. This allows to select a subset of potential drivers. We then compute sets of driving quickest paths, and design a substitution process. Finally, among all admissible solutions, we select a best one based on the earliest arrival time. We provide numerical results using geographical maps, real data and public transportation timetabling. Our numerical results show the effectiveness of our system, which improves rider’s arrival time compared to the traditional multi-modal path. The running time of our approach remains reasonable to use real-time transportation application.

International audience; To estimate the genetic diversity and population structure for a better understanding of the spread of Botrytis cinerea, we genotyped with nine microsatellite markers 174 isolates collected from four greenhouses during three growing seasons in the region of Bejaia. Four of these isolates were detected as Botrytis pseudocinerea according to the allele size at locus Bc6. For all other isolates further studied, all loci were polymorphic, with the mean number of alleles per locus ranging from 2.77 to 5.22. Considerable genetic variability was detected in all subpopulations (D* > 0.87; Hnb > 0.40). Based on the standardized index of association analysis, significant but low levels of clonality occurred, not excluding the possibility of recombination (rD = 0.07, P < 0.001). A total of 109 haplotypes were characterized among the isolates, few of which were shared between subpopulations. This, together with moderate genetic differentiation among subpopulations according to the geographical origin (0.080 < FST < 0.167), suggested a low level of inoculum exchange among greenhouses and little carry-over of inoculum from one sampling season to the next. The importance of genetic structure of B. cinerea populations is discussed and should be taken into consideration for the management of grey mould.

We consider a mix transportation problem, which allows to combine a multi-modal public and a ride-sharing transports, in a dynamic environment. The main idea of our approach consists in labelling interesting nodes of a geographical map with information about either riders or drivers, in so-called buckets. Based on the information contained in these buckets, we compute admissible ride-sharing possibilities. To restrict the needed amount of memory, among the different stops along a public transportation path, we only consider the transshipment nodes, where travellers have to make a change between two modes. Each of those stops are potential pick-up or drop-off stops for ride-sharing. We consider a drivers’ maximal waiting time, as well as the maximal driving detour time depending on the actual drive. Each new drive activates a search for new ride-sharing of existing riders. Each new ride activates another process which searches for potential drivers. Among all admissible ride-sharing possibilities, only those which best improve the earliest arrival time are selected. We provide numerical results using real road network of the Lorraine region (FR) and real data provided by a local company. Our numerical experiment shows a running time of a few seconds, suitable for a new real-time transportation application.

Traditional medicine has been used worldwide for centuries to cure or prevent disease and for male or female contraception. Only a few studies have directly investigated the effects of herbal compounds on spermatozoa. In this study, essential oil from Thymus munbyanus was extracted and its effect on human spermatozoa in vitro was analysed. Gas chromatography and Gas chromatography – mass spectrometry analyses identified 64 components, accounting for 98.9% of the composition of the oil. The principal components were thymol (52.0%), γ-terpinene (11.0%), ρ-cymene (8.5%) and carvacrol (5.2%). Freshly ejaculated spermatozoa was exposed from control individuals to various doses of the essential oil for different time periods, and recorded the vitality, the mean motility, the movement characteristics (computer-aided sperm analysis), the morphology and the ability to undergo protein hyperphosphorylation and acrosomal reaction, which constitute two markers of sperm capacitation and fertilizing ability. In vitro , both the essential oil extracted from T. munbyanus and thymol, the principal compound present in this oil, impaired human sperm motility and its capacity to undergo hyperphosphorylation and acrosome reaction. These compounds may, therefore, be of interest in the field of reproductive biology, as potential anti-spermatic agents.

Ridesharing concerns people that are willing to intelligently ride in order to save money and protect environment. The idea is based on a better use of private car. More precisely, it aims to bring together individuals that share, even partially, a trip. In the recurring ridesharing problem, when an offer is matched with a demand, the driver picks-up the rider at his starting location, drops him off at his ending location and continues to his target location. This approach lacks of flexibility and misses some possible matchings. In this paper, we propose a new ridesharing approach in which a driver and a rider accept to meet in an intermediate starting location and to separate in another intermediate ending location. This allows to reduce both the driver's detour and the total travel cost. We propose exact and heuristic methods to compute meeting points that minimize the total travel cost of the driver and the rider. We analyze their empirical performance on a set of real road networks consisting of up to 3,5 million nodes and 8,7 million edges. Our experimental analysis shows that our heuristics provide efficient performances within short CPU times and improves the recurring ridesharing approach.

International audience; Several methods can be used to provide water to plants in cropping systems where irrigation is necessary. For instance, drip irrigation has recently received much attention due to its advantages for water conservation. The type of irrigation can also impact the development of several pathogens responsible for soilborne diseases. Here, we studied the effect of drip irrigation and furrow irrigation on the development of grey mould, caused by the airborne fungus Botrytis cinerea, on tomato plants. A field experiment was conducted in 2004 in five unheated greenhouses. Plants were examined individually every 8 days and the proportion of plants attacked by grey mould on leaves, stems or fruits was recorded from the end of March until the end of June. Our results show that the attacks of Botrytis on the stems occurred earlier in furrow irrigation, 98.8 days after planting on average, than in drip irrigation: 106.3 days after planting. The kinetics of plant infection on stems, leaves and fruits were higher under furrow than under drip irrigation. Disease severity was measured by the average number of stem lesions per plant. Disease severity was higher in plants under furrow than under drip irrigation, reaching 1.32 and 0.99, respectively, at the end of June. Plant mortality due to grey mould was first recorded at 94 and 110 days after planting, respectively, in the furrow- and in the drip- irrigated greenhouses. These results suggest that drip irrigation could be a useful tool for the implementation of integrated protection schemes and for reducing the use of pesticides in unheated tomato greenhouses. They may also provide an additional incentive for growers to switch from furrow to drip irrigation in sheltered tomato production

Gray mold, caused by Botrytis cinerea fungus, is a major aerial fungal disease, which affects various important agronomical crops. Phenotypic and genotypic diversity of B. cinerea is very strong and its quick adaptability to selective pressure was reported, which makes the control methods very limited. The objectives of this work aim to study the phenotypic variability exhibited by isolates of B. cinerea in response to high temperatures. This by studying firstly the development of gray mold and temperature fluctuations in commercial tomato greenhouses in the region of Bejaia during two seasons (2012 and 2013), and then, by studying of the effect of temperature on the mycelial growth and spore germination of local isolates. The effect of high temperatures on the development in vitro, aggressiveness on tomato leaflets of B. cinerea isolates collected from different geographical regions (Algeria, France and Norway), as well as the aggressiveness of these isolates on tomato plant in optimal conditions were reported. A final objective aims to study the genotypical variability of B. cinerea populations isolated in tomato greenhouses of Bejaia region. The development of gray mold in tomato greenhouse, despite the high air temperatures recorded inside unheated greenhouse, which is confirmed by the rate of infected plants from the beginning (3.02%) and end of the experiment (25%), respectively. A significant difference was found between local isolates on spore germination and mycelial growth rate differences. Over 90% of the spores were germinated at 21 °C, whereas at 28 °C and 30 °C, spore germination was reduced to less than 79% and 50% respectively after 10 hours. The mycelial growth rate was significantly reduced at 28 °C and 30 °C for all tested isolates. No isolates were developed at 32 °C. The effect of temperature on the aggressiveness of B. cinerea isolates on tomato leaflets and full plants revealed considerable variability between tested isolates. Temperature of 30 °C corresponds to the inhibition of aggressiveness on tomato leaflets. No significant differences in aggressiveness were detected among isolates of B. cinerea collected in Algeria, France and Norway. Finally, a genotypic analysis of 174 isolates using nine microsatellite markers identified four of these isolates as Botrytis pseudocinerea based on the size of the allele at locus Bc6. For all other isolates studied, all loci are polymorphic, with an average number of alleles per locus from 2.77 to 5.22. Considerable genetic variability was detected in all subpopulations (D*>0.87; HNB>0.40). Based on the analysis of the standardized index association, a significant low level of clonality was observed, without excluding the possibility of recombination (rD=0.07, P B. cinerea populations was discussed and should be considered for the management of gray mold., La pourriture grise, causée par le champignon Botrytis cinerea, est l'une des principales maladies fongiques aériennes qui touche diverses cultures d’importance agronomique. La diversité phénotypique et génotypique de B. cinerea est très grande et la capacité d’adaptation de ce champignon à une pression sélective est rapide, ce qui limite considérablement les méthodes de lutte entreprises. Les objectifs de ce travail visent à étudier la variabilité phénotypique montrée par des isolats de B. cinerea en réponse aux températures élevées. Ceci est conduit par l'étude du développement de la pourriture grise et les fluctuations de températures à l’intérieur des serres commerciales de tomates de la région de Bejaia durant deux saisons (2012 et 2013), ainsi que par l'étude de l’effet de la température sur la croissance mycélienne et la germination des spores des isolats locaux. L’effet des températures élevées sur le développement in vitro, l’agressivité sur des folioles de tomate des isolats de B. cinerea isolés dans les différentes régions géographiques (Algérie, France et Norvège), ainsi que l’agressivité de ces isolats sur la plante entière de tomate en conditions optimales sont également abordés. Un dernier objectif vise à étudier la variabilité génotypique des populations de B. cinerea isolés dans les serres de tomates de la région de Bejaia. Le développement de la pourriture grise sous les serres de tomates augmente malgré les températures élevées de l'air à l'intérieur de serre non chauffée, ce qui est confirmé par le taux de plantes infectées depuis le début (3,02%) et la fin de l'expérimentation (25%), respectivement. Des différences significatives sont enregistrées entre les isolats locaux sur la germination des spores, et la vitesse de croissance mycélienne. Plus de 90% des spores sont germées à 21 °C, tandis qu'à 28 °C et 30 °C, la germination des spores a été réduite à moins de 79% et 50% respectivement au bout de 10 heures. La vitesse de croissance mycélienne a été significativement réduite à 28 °C et 30 °C pour tous les isolats testés. Aucun des isolats ne s'est développé à 32 °C. L’effet de la température sur l’agressivité des isolats de B. cinerea sur folioles de tomates et sur les plantes entières a révélé une grande variabilité entre les isolats testés. 30 °C, correspond à la température d’inhibition de l’agressivité sur les folioles de tomate. Aucune différence significative de l’agressivité n’a été détectée entre les isolats de B. cinerea collectés en Algérie, France et Norvège. Enfin, nous avons analysé génotypiquement 174 isolats avec neuf marqueurs microsatellites. Quatre d'entre eux ont été identifiés comme Botrytis pseudocinerea en fonction de la taille de l'allèle au locus Bc6. Pour tous les autres isolats étudiés, tous les loci ont été polymorphes, avec un nombre moyen d'allèles par locus allant de 2,77 à 5,22. Une variabilité génétique considérable a été détectée dans toutes les sous-populations (D*>0,87 ; HNB>0,40). Sur la base de l’analyse de l'indice l'association standardisé, un faible niveau de clonalité a été observé, sans exclure la possibilité d'une recombinaison (rD=0,07, PB. cinerea a été discutée et devrait être pris en considération pour la gestion de la pourriture grise.