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Biochemical and molecular characterization of a new glycoside hydrolase family 17 from Sclerotinia sclerotiorum.

A. Ezzine 1*

H. Chahed 1

M. Hannachi 1

J. Hardouin 2

T. Jouenne 2 

M.N. Marzouki 1


1 Laboratoire d’Ingénierie des Protéines et Molécules Bioactives (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, Tunis cedex 1080, Tunisia.

2 Laboratoire Polymères Biopolymères Surfaces (PBS), UMR 6270 CNRS, Université de Rouen, F-76821 Mont-Saint-Aignan cedex


Abstract - β-1,3-glucanases are known to be involved in different morphogenetic processes in fungi. Here, we perform a rapid proteomic analysis of the induced secretome of Sclerotinia sclerotiorum using Label free mass spectrometry analysis to identify a new laminarinase belonging to the family 17 of glycoside hydrolases so called Lam17_S.sc. Only one extracellular enzyme with laminarinase activity has been identified and then biochemically characterized. The genomic DNA and cDNA sequences were amplified by PCR and RT-PCR respectively, cloned and sequenced to reveal a gene with two intron sequences. The open reading frame of 909 bp encoded a polypeptide of 302 amino acids having a calculated molecular mass of 32312.06 Da. Yet, the molecular modeling and comparative investigation of different resolved structures showed that this laminarinase belongs to the family 17 of glycoside hydrolases. Further studies using the recombinant form of this enzyme for biotechnological applications are investigated.


Keywords: Computational biology, Filamentous fungi, Glucanases, Protein modelling, Sclerotinia sclerotiorum.


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Soil microorganisms alleviates the negative effect of salinity on morphophysiological characteristics during growth stages of durum wheat genotypes

K. Boudabous1*

N. Ben Aissa1

Y. Trifa1

A. Sahli1

H. Slim Amara1


1 National Institute of Agriculture of Tunisia, 43, Avenue Charles Nicole, 1082 Tunis, Tunisia.


Abstract - The rhizosphere is a biologically active zone in the soil around the roots of plants. Root microorganism interaction in the rhizosphere can be beneficial to the plant mainly in stress conditions. In order to investigate their interactions, contrasted tests were carried out. Four durum wheat varieties, too are landraces (Agili glabre and Bayadha) and too are improved (Razzek and Maali) were planted in greenhouse under sterilized and non-sterilized soil to evaluate their physiological comparative performance under water saline and non-saline irrigation conditions. Morpho-physiological responses to salinity (0 and 12dSm-1) were evaluated for contrasting genotypes: the chlorophyll uorescence (Fv/Fm); relative water content (RWC) and leaf area (LA), during vegetative and reproductive stages. Results showed that salinity affected negatively all parameters mainly in sterilized conditions. The leaf area index was much less affected by salinity. However, (Fv/Fm) and WRC were significantly affected by salinity (P<0.01) and microbial activity mainly at vegetative stage. Agili glabre and Maali found to be the most tolerant even in sterilized conditions. Correlations studies showed significant positive correlations (r=0.54, P<0.01; r=74, P<0.01) between MBC and both the Fv/Fm and WRC respectively. These results suggested that microorganisms might be usefull for salinity tolerant genotypes primarily at vegetative stages.


Keywords: Salinity, durum wheat, microbial biomass, growth stages, physiological parameters.


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Improving yield and fruit quality of peach cv. ‘Flordastar’ by potassium foliar spray associated to regulated deficit irrigation

S. Dbara1*

T. Gader2

M. Ben Mimoun3


1 Centre régional des recherches en horticulture et agriculture biologique, Chott Mariem, BP 57 Chott Mariem 4042 Tunisia.

2 Institut Supérieur Agronomique de Chott Mariem, Tunisia.

3 Institut National Agronomique de Tunisie, 43 Avenue Charles Nicolle, 1082 Tunisia.

Abstract - The importance of potassium leaf application was highlighted in this study. A field experiment was carried out in a commercial orchard of early peach cultivar ‘Flordastar’. Trees were subjected to combination of two irrigation regimes (FI and DI were respectively full and deficit irrigation) and foliar potassium spray (K+) and no potassium supply (K-). Four treatments were consequently considered such as FI/K+, FI/K-, DI/K+ and DI/K-. Yield, fruit quality and vegetative growth were measured for each treatment. Results showed differences between treatments. At harvest, the highest yield was observed in trees which received potassium application especially with FI. For both treatments FI/K+ and DI/K+ fruit diameter and total soluble solids were increased however firmness was reduced. Measurements of vegetative growth showed slight differences between treatments except FI/K+ which increased shoot length. Potassium leaf content was high in K+ treatments.



Keywords: potassium, irrigation, yield, quality, peach.


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Effet du mode de semis et de la rotation culturale sur les paramètres de croissance et les composantes de rendement du blé dur (Triticum durum Desf.) variété « Karim »







¹Laboratoire des sciences horticoles, Institut National Agronomique de Tunisie, Université de Carthage.

² Laboratoire des sciences horticoles, Ecole Supérieure d’Agriculture de Mateur, Université de Carthage.

³Institut National des Grandes Cultures


Abstract - This work was performed at the Koudiat Experimental Station of the National Institute of field crops. He studied different cropping systems practiced in the upper semi arid north western Tunisia. These systems have durum wheat (Triticum durum Desf.) "Karim" variety as the main crop with a biennial rotation previous legume (faba beans) and cereals (barley or oats), which forms the major previous crops of durum wheat in rainfed cereal systems north west Tunisia. The aim of the work is to study the behavior of durum wheat (growth parameters and yield components) under two planting methods (conventional cropping (SC) and No till (SD)) and with three different previous crops (barley ( O), oats (Av) and faba bean (February). This study showed that the effect of No till seeding can be significant on growth parameters and components yields than when bound to a previous crop oats or faba bean ( height Bd / Fev direct seeding is higher than in conventional croping with over 12.5% and the content of protein in the same seeding mode with over 4.66%) and direct seeding effect becomes significant from the third and fourth year of cultivation (the case of the leaf surface, the weight of thousand seeds and efficiency of water use straw and seed). In addition to that, this study confirmed the previous barley does not improve the components of durum wheat yields is driving some of the crop.


Keywords: No tillage, previous crop, growth, yield components


Résumé - Ce travail a été réalisé à la station expérimentale Kodiat de l’institut national des grandes cultures. Il a étudié différents systèmes de culture pratiqué dans le semi aride supérieur du nord ouest de la Tunisie. Ces systèmes ont le blé dur (Triticum durum Desf.) variété « Karim » comme culture principale avec une rotation biennale à précédent légumineuse (féverole) et céréale (orge ou avoine) qui forme les principales cultures précédentes du blé dur dans les systèmes céréaliers pluviale du nord ouest de la Tunisie. L’objectif du travail est d’étudier le comportement du blé dur (paramètres de croissance et composantes de rendement) sous deux modes de semis (semis conventionnel (SC) et semis direct (SD)) et avec trois différents précédents culturaux (orge (O), avoine (Av) et féverole (Fev). Cette étude a montré que l’effet du semis direct peut être significatif sur les paramètres de croissance et composantes de rendements que lorsqu’il est lié à un précédent cultural avoine ou féverole (hauteur de Bd/Fev en semis direct est élevée à celui en semis conventionnel avec plus de 12.5 % et en teneur en protéine dans le même mode de semis avec plus de 4.66 % ) et que l’effet semis directe est devient significatif à partir de la troisième et quatrième année de culture (cas de la surface foliaire, le poids de mille graine et de l’efficience de l’utilisation de l’eau de la paille et de graine). De plus, cette étude a confirmé que le précédent orge n’améliore pas les composantes de rendements de blé dur quelques soit la conduite de culture.


Mots clés: Semis direct. Précédent cultural. Croissance. Composantes de rendement


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Effet du solvant et de la méthode d’extraction sur la teneur en composés phénoliques et les potentialités antioxydantes d’Euphorbia helioscopia






1Laboratoire des Plantes Aromatiques et Médicinales, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-Lif; Tunisie.

2Ecole Supérieure des Sciences et Techniques de la Santé de Tunis, BP 176, Bab Souika, Tunisie.


Abstract - This work proposes to optimize the parameters extraction of phenolic compounds from the aerial part of Euphorbia helioscopia native Sidi Thabet. The following first stage was designed to study to study the effect of solvent polarity and extraction technique on antioxidant capacities of the species. The results showed that the mixed aqueous extracts and have high levels of phenolic compounds, irrespective of the solvent used. Moreover, depending on the solvent studied, it was noted that the decoction showed high levels of the compounds. As against, the acetone and 70% ethanol extracts show strong antioxidant capabilities. The second step was devoted to the study of the effect of three extraction techniques on the antioxidant capacity of E. helioscopia. The results revealed that the sonication is most suitable for the extraction of phenolic compounds and thus showing high levels of polyphenols and very high antioxidant capacities relative to soxhlet and simple maceration extraction.



Keywords: Euphorbia helioscopia, phenolic compounds, antioxidant activity, solvent extraction, extraction techniques.


Résumé - Ce travail propose d’optimiser les paramètres d’extraction des composés phénoliques de la partie aérienne d’Euphorbia helioscopia originaire de Sidi Thabet. La première étape suivante fut destinée à l’étude de l’effet des différents solvants d’extraction sur les teneurs des composés phénoliques et les capacités antioxydantes de cette espèce. Les résultats ont montré que les extraits aqueux et ceux mixtes possèdent des teneurs élevées en composés phénoliques, ceci indépendamment du solvant utilisé. D’autre part, en fonction du solvant étudié, on a remarqué qu’au niveau de la partie aérienne, le décocté a montré les fortes teneurs en composés. Par contre, les extraits acétoniques et éthanoliques à 70% montrent les fortes capacités antioxydantes. La deuxième étape a été consacrée à l’étude de l’effet de 3 techniques d’extraction sur la capacité antioxydante d’E. helioscopia. Les résultats ont révélé que la sonication est la plus convenable pour l’extraction des composés phénoliques et montrant ainsi les fortes teneurs en polyphénols et des activités antioxydantes très élevées par rapport au soxhlet et à la macération.


Mots clés: Euphorbia helioscopia, composés phénoliques, activité antioxydante, solvant d’extraction, techniques d’extraction.


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This article is published under license to Journal of New Sciences. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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