K. Ennouri¹

R. Ben Ayed^1*

H. Ben Hassen²

¹ Centre of Biotechnology of Sfax, PB ‘1177’, 3018 Sfax, Tunisia

² Laboratory of Physics, Mathematics and Applications. Faculty of Sciences of Sfax, Tunisia

Abstract - The bacterium Bacillus thuringiensis (Bt) is a spore forming microorganism that produces an insecticidal crystalline protein (ICP) making it a famous biopesticide. The ICPs are also referred to as Cry proteins and include delta-endotoxins, which cause mortality of insects classified to several orders, namely, Coleoptera, Diptera and Lepidoptera.

Statistical methods were carried out to ameliorate the fermentation medium composition for the production of bacterial delta-endotoxins in submerged cultures. An experimental statistical design was used to measure the effects of different components in the medium. The concentrations of starch and soybean meal, considered as the main carbon and nitrogen sources for bacterial growth, respectively, FeSO₄ and MgSO₄ were found to increase Bacillus sp. delta-endotoxin production. Different mathematical models were developed and interaction between all ingredients was studied. In concordance with coefficient of determination (R²) value, well known as the most important criterion for predictive models success, the best model was validated and thus demonstrated the effect of interaction and then can precisely predict the production of delta-endotoxins by studied bacterium. With a limited number of experiments, this method allowed to obtain promoting results.

Keywords: Bacillus thuringiensis / delta-endotoxins / coefficient of determination / interaction / statistical design.

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N. Abdi*

I. Hmissi

M. Bouraoui

B. L’taief

B. Sifi

National Institute for Agricultural Research, Laboratory of Agricultural Science and Technology, Av. Hédi Karray 2080 Ariana, Tunis, Tunisia.

Abstract - The present work describes whether the changes in the activities of antioxidant enzymes and the levels of some non-enzymatic antioxidants could be used as markers of salt tolerance in common bean (Phaseolus vulgaris L.) inoculated by rhizobia strain (Ar02) that belonging to the sinorhizobium genera. Common bean-rhizobia symbiosis was exposed to NaCl i.e., (100mM) in perlite culture. Nodulation, plant dry weight, total phenols, proline content, hydrogen peroxide (H₂O₂), peroxidase (PO), polyphenol oxidase (PPO) were analyzed. The results indicated that salt stress decreased nodulation and growth parameters. Under salt stress, shoot exhibiting the highest in N content (60%). In addition, K⁺ and Na⁺ uptake in shoot under salt stress was increased significantly by 8.55% and 53.17% respectively. This constraint (100mM) affected levels of H₂O₂ remained. Salt stress markedly enhanced the activities of H₂O₂ and PPO in leaves of common bean-rhizobia symbiosis. Salt stress exhibited the root phenols secretion and proline accumulation. Extent increase was noted at flowering stage (10.93 %) that show the highest values of phenol content (160mg.g^-1 FM). Increase of different parameters in plant need many investigations of mechanisms that improve the Common bean-rhizobia symbiosis efficiency under salt stress.

Keywords: Common bean / rhizobia / salt stress / oxidative stress / peroxidase / proline.

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M. Jemni ^1,2,*

M. Otón ³

M. Souza ⁴

M.H. Dhouibi ⁵

A. Ferchichi ⁶

F. Artés ^3,7

¹ Regional Research Center in Oasis Agriculture Degache

² Aridlands and Oases Cropping Laboratory, the Arid Regions Institute of Medenine, Tunisia

³ Institute of Plant Biotechnology, Universidad Politécnica de Cartagena (UPCT), Campus Muralla del Mar, Cartagena, Murcia, Spain

⁴ University of Mato Grosso/Alta Floresta, Brazil

⁵ Laboratory of Entomology. National Institute of Agronomic of Tunisia

⁶ Rural Laboratory. National Institute of Agronomic of Tunisia

⁷ Postharvest and Refrigeration Group, Department of Food Engineering, UPCT, Cartagena, Murcia, Spain

Abstract - Among the vast insect pest attacks suffered by date palm, the carob moth (Ectomyelois ceratoniae) is the most destructive causing the largest damages every season. Methyl bromide is the most effective insecticide for date palm but its use will be shortly forbidden and sustainable alternatives must be found. The current work firstly evaluated the efficacy of the eco-friendly ozone gas treatment against E. ceratoniae at larvae stage on intentionally infected Deglet Nour dates. Results showed that the mortality of E. ceratoniae depended on the ozone level and the exposure time. In fact, with 12.2 mg L^-1 for 80 min the carob moth mortality was ten-fold higher (82 ± 3%) than in control samples (8 ± 3%). This allows advancing in knowing the effect of ozone gas as an emergent alternative to methyl bromide on larvae of E. ceratoniae and on its possible application at commercial scale by the handling industry of fresh date palm. But, further studies are required to reach a 100% of carob moth mortality.

Keywords: Postharvest sustainable fumigant / Ectomyelois ceratoniae / Alternative to methyl bromide / Deglet Nour cv.

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H. Snoussi Trifa ^*

E. Jedidi

M. Ben Slimane Harbi

Horticultural Laboratory, Tunisian National Agronomic Research Institute (INRAT), Rue Hedi Karray, 1004 Tunis, Tunisia

Abstract - Tunisia harbor an interesting germplasm of cultivated grapes and their wild relatives. Within this wide diversity, Razzegui has the biggest berry size and can, therefore, be considered as one of the most promising cultivars for commercial production or as a genitor in improvement programs. Razzégui, is part of genetic heritage of value, which should well be characterized and developed. It is a grapevine with flowers, which are morphologically hermaphrodites but physiologically females with reflex stamens. This floral type occurs most often in dioecious Vitis sylvestris, contrary to Vitis vinifera L. with flowers predominantly hermaphrodites. Our study aims at understand the relation between Razzégui and the other cultivated and Tunisian wild native grapevines. We have studied the ampelographic characteristics of Razzégui by means of 34 descriptors of the International Organization of the Vine and the Wine (OIV) for which 20 levels of expression were tested. In addition, cytogenetics of this grapevine were carried out and allowed the evaluation of its chromosomal constitution. Finally, 9 microsatellites loci VVS2, VVMD5, VVMD7, ssrVrZAG21, ssrVrZAG47, ssrVrZAG62, ssrVrZAG64, ssrVrZAG79 and ssrVrZAG83 were used on 54 genotypes including Razzégui. We have shown an intermediate position of Razzégui between cultivated and wild grapevines, arguing for a single type that could be considered as an intrinsically wild grapevine with characters of cultivated variety.

Keywords: Vitis vinifera / Vitis sylvestris / floral type / descriptors / ploidy / microsatellites / grapevine of Tunisia / domestication.

Résumé - Les origines des cépages cultivés de Tunisie demeurent très mal connues. Au sein d'une large diversité d'un encépagement autochtone tunisien se distingue le Razzégui considéré comme étant le meilleur cépage de la gamme des vignes autochtones cultivées puisqu'il est décrit comme le plus gros des raisins de table de Tunisie. Le Razzégui, fait partie d’un patrimoine génétique de valeur, qui devrait être bien caractérisé et valorisé. C'est un cépage à fleurs morphologiquement hermaphrodites mais physiologiquement femelles à étamines reflexes. Ce type floral est retrouvé le plus souvent chez les Vitis sylvestris dioïques, contrairement aux Vitis vinifera L. à fleurs à prédominance hermaphrodites. Au sein d’une collection de vignes autochtones tunisiennes cultivées et spontanées, la position de ce cépage demeure confuse. Cette étude a d'abord visé la précision des caractéristiques ampélographiques du Razzégui moyennant 34 descripteurs du code de l'Organisation internationale de la vigne et du vin (OIV) pour lesquels 20 niveaux d'expression ont été testés. On a par ailleurs, réalisé la cytogénétique de ce cépage qui a permis d'évaluer sa constitution chromosomique. Enfin, on s'est proposé de rechercher une éventuelle proximité génétique au sein d'une gamme de variétés cultivées et d'écotypes spontanés de Tunisie. Le Razzégui, avec 54 autres vignes autochtones ont été analysés avec l’outil moléculaire. Pour cela, 9 locus microsatellites VVS2, VVMD5, VVMD7, ssrVrZAG21, ssrVrZAG47, ssrVrZAG62, ssrVrZAG64, ssrVrZAG79 et ssrVrZAG83 ont été analysés. Au total, 54 génotypes uniques ont été observés. Les résultats ayant montré une position intermédiaire du Razzégui, entre vignes cultivées et spontanées, militent en faveur d'un cépage unique pouvant être considéré comme une vigne intrinsèquement spontanée avec des caractères de vigne cultivée.

Mots-clés: Vitis vinifera / Vitis sylvestris / type floral, descripteurs / ploïdie / microsatellites / cépage de Tunisie / domestication.

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