Caractérisation phénotypique et génotypique des souches de <em>Botrytis cinerea</em> ; agent causal de la pourriture grise sur tomate

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

Comparison of<em> Botrytis cinerea</em> populations collected from tomato greenhouses in Northern Algeria

International audienceTo 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 B. cinerea populations is discussed and should be taken into consideration for the management of grey mould

Genetic diversity and inoculum exchange of Botrytis cinerea between tomato greenhouses in northern Algeria

To estimate the genetic diversity 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

Fecal Carriage of Extended-Spectrum β-Lactamase and Carbapenemase-Producing Enterobacterales Strains in Patients with Colorectal Cancer in the Oncology Unit of Amizour Hospital, Algeria: A Prospective Cohort Study

International audienceThe prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) is now disseminated worldwide. This study aims to describe the prevalence of ESBL and CPE fecal carriage in colorectal cancer patients. Methods: All patients admitted to the oncology service of Amizour hospital (Algeria) for colorectal cancer chemotherapy from March to May 2019 were screened for ESBL-E or CPE fecal carriage. After culturing on chromogenic media, the presumptive colonies were identified by mass spectroscopy. Antibiotic susceptibility testing was performed according to the European Committee on Antimicrobial Susceptibility Testing. The β-lactamases encoding genes and plasmid-mediated quinolone-resistant genes were screened by PCR and sequencing. Results: ESBL-E strains were recovered from rectal swabs in 6 patients (14.3%) and only 1 patient (2.4%) was found a carrier for OXA-48-producing Klebsiella pneumoniae. The most frequently encountered species among ESBL-E was Escherichia coli (n = 5), followed by K. pneumoniae (n = 1). PCR and sequencing showed that four isolates harbored the blaCTX-M-15 gene and two strains harbored the blaCTX-M-14 gene. Also, one strain of K. pneumoniae was found to harbor both qepA and qnrS genes. Conclusion: This study highlighted the fecal carriage of ESBL-E and OXA-48-producing Enterobacterales strains in colorectal cancer patients