Improvement of Callogenesis Ability by Selecting a Better Hormonal Balance in Potato (Solanum tuberosum L).

Response in tissue culture is highly genotype dependent, significant genotypic diferences in callus initiation response were observed among both potato genotype investigated. The Spunta variety devleops the best calogenesis in all media compared to Kondor variety depending on hormones concentration,there is a range of variations in days needed for callus initiation,percentage of explant that developed callus, its texture, color and the degre of its formation.Our resutls chow that the callus depends on explant type.Sprout explant respond best to callus formation. the amount of callus ranges from 60% to 90 % for Spunta .Callus color after eight weekwas light green or green yelow for both varieties.The higest amount of callus 100% was obtained with the combination (NAAxBAP)(0.5/1, medium M2) and (2/2 ,medium M3) with Kondor bud explant .In media M1(1/0.5 mg/l),M2 (0.5/1 mg/l) and M3 (2/2 mg/l) with sprout explant of Spunta the amount of 80 %was noted,callus in media M1 and M2 produced microtubers,shoots and roots

Etude Des Effets Des Régulateurs De Croissance Sur La Les Stades De Prolifération Et De Développement De La Pomme De Terre (Solanum Tuberosum. L) In Vitro

The aim of this study is to determine the effects of different concentrations and combinations of the phytohormones, 1-naphthaleneacetic acid (NAA), and 6-benzylaminopurine (BAP): M1 (0.5 mg / l +1 mg / l), M2 (1 mg / l + 0.5 mg / l) , M3 (2 mg / l +2 mg / l), M4 (0.5 mg / l + l mg / l, NAA), M5 (1.0 mg / l + l mg / l , NAA), and M6 (2.0 mg / l + l mg / l, NAA). This study was carried out in dark condition on callus induction of potato plants (Solanum tuberosum L.) cultivars from potato tuber bud so as to demonstrate the role of light. The callus initiation begins after 7 days of incubation for all studied media. After two months of incubation, the better development of callus was noted in Spunta variety by using medium M1, M2, M3, and M6. The calluses took a compact structure of brown-white color for both varieties with a callus induction rate of 20- 40%. This was collected with kondor variety for M2 and (M3, M4, M5) media respectively and 10-30% for M4 (M1, M2, M3) for Spunta variety also. The highest fresh weight was recorded on M2 medium with 0.26g for Kondor variety and 0.93g for Spunta variety

Study of root para-nodules formation in wheat (Triticum durum) inoculated with Frankia strain CcI3 and treated with 2, 4-dichlorophenoxyacetate (2, 4-D)

Frankia strains can induce N2-fixing root nodules on certain non-leguminous plants. It is known that exogenous application of 2,4-dichlorophenoxyacetate (2,4-D) affects root morphology. In this work, wheat roots were treated with 2,4-D and inoculated with the actinomycete Frankia. Wheat plants grew in a growth chamber with hydroponic medium. Binocular observation revealed that para-nodules were formed when wheat roots were inoculated with Frankia and the root length was enhanced. When the inoculation with Frankia was combined to 2,4-D treatment, the para-nodules formed were bigger and more numerous, while the root length was shortened.Keywords: Frankia, wheat, roots, para-nodules, 2,4-dichlorophenoxyacetateAfrican Journal of Biotechnology Vol. 12(35), pp. 5427-543

Composite Actinorhizal Plants with Transgenic Roots for the Study of Symbiotic Associations with Frankia

More than 200 species of dicotyledonous plants belonging to eight different families and 24 genera can establish actinorhizal symbiosis with the nitrogen-fixing soil actinomycete Frankia. Compared to the symbiotic interaction between legumes and rhizobia, little is known about the molecular basis of the infection process and nodule formation in actinorhizal plants. Here, we review a gene transfer system based on Agrobacterium rhizogenes that opens the possibility to rapidly analyze the function of candidate symbiotic genes. The transformation protocol generates ?composite plants? that consist of a nontransgenic aerial part with transformed hairy roots. Composite plants have already been obtained in three different species of actinorhizal plants, including the tropical tree species Casuarina glauca, the Patagonian shrub Discaria trinervis, and the nonwoody plant Datisca glomerata. The potential of this technique to advancing our understanding of the molecular mechanisms underlying infection by Frankia is demonstrated by functional analyses of symbiotic genes.Fil: Meriem Benabdoun, Faiza. Université Mentouri; ArgeliaFil: Nambiar Veetil, Mathish. No especifíca;Fil: Imanishi, Leandro Ezequiel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Svistoonoff, Sergio. No especifíca;Fil: Ykhlef, Nadia. Université Mentouri; ArgeliaFil: Gherbi, Hassen. No especifíca;Fil: Franche, Claudine. No especifíca

QTL analysis of yield-related traits in sunflower under different water treatments

A set of sunflower recombinant inbred lines (RILs) was used to study agronomical traits under greenhouse and field conditions each with two water treatments and three replications. The difference among RILs was significant for all the traits studied in all conditions; and water treatment × RILs interaction was also observed for most of the traits in both field and greenhouse conditions. Because of the low rate of drought stress, this part of field data are not informative. Several quantitative trait loci (QTLs) were identified for yield‐related traits with the percentage of phenotypic variance explained by QTLs (R 2) ranging from 4% to 40%. Several QTLs for grain yield per plant (GYP) under four water treatments were identified on different linkage groups, among which two were specific to a single treatment (GYPN.4.1 , GYPI.7.1 ). Three QTLs for GYP were overlapped with several QTLs for drought‐adaptative traits detected in our previous study (Poormohammad Kiani et al. 2007b). The whole results do highlight interesting genomic regions for marker‐based breeding programmes for drought tolerance in sunflower

Role of Glutamate-Derived Amino Acids under Stress Conditions: The Case of Glutamine and Proline

A number of metabolic adaptive processes have been evolved in higher plants to cope with environmental stresses. Being sessile organisms unable to escape stressful conditions, plant survival is critically dependent by the rapid establishment of metabolic and physiologic responses that collectively attenuate or block the harmful effects of environmental injuries. Drought, cold and salt stress, in particular, are major threats for plant life, and cause, on a worldwide scale, dramatic losses in crop yields, especially in many developing countries and arid or semi-arid regions. The amino acids derived from glutamic acid, such as proline, γ-amino butyric acid (GABA), glutamine, arginine, as well as their close derivatives polyamines and nitric oxide (NO), play a special role in the metabolic adaptations of plants during abiotic stress. Glutamate itself seems to be not directly affected by stress conditions, but in reality plays an essential role as a donor of stress-related amino acids and metabolites as well as signal molecule involved in stress responses. Indeed most amino acids belonging to the glutamate family accumulate in large amounts under stress conditions and are thought to improve plant stress tolerance, although the molecular mechanisms through which these amino acids exert their action are still poorly understood. The study of the molecular and biochemical mechanisms by which this class of amino acids can improve plant tolerance to environmental stresses is of paramount importance in basic biology and can be regarded as a preliminary step towards the development of stress-tolerant and high-yield crop plants. The development of stress-tolerant crops of high productivity is a major issue in current research because of the increasing food demand of a growing world population, combined with the harmful effects of global warming, particularly drought, salinity and extreme temperatures. In this chapter the current state of the art of the glutamate-derived amino acids under stress conditions will be thoroughly revised and critically discussed with particular attention to the role of glutamine and proline for possible amelioration of yield and stress tolerance of agricultural crops

Pigments photosynthétiques, enzymes antioxydantes et potentiel osmotique foliaire de dix génotypes de blé dur (Triticum durum) : effet du stress hydrique

L’ajustement osmotique, les pigments photosynthétiques et les changements d’activités des antioxydants enzymatiques ont été évalués chez dix génotypes de blé dur (Triticum durum) soumis à des conditions de stress hydrique. Les plantules de blé ont germé en hydroponie, en chambre de culture. Le stress hydrique a été appliqué aux quatrième et cinquième stades de la feuille par l’ajout d’une solution de polyéthylène glycol (PEG 6000) (-0,49 MPa). Le potentiel osmotique ainsi que la teneur en chlorophylle totale (Chl a+b) et en caroténoïdes (Car) ont été déterminés. Des analyses électrophorétiques ont été effectuées pour trois enzymes antioxydantes, soit la superoxyde dismutase (SOD), la guaïacol peroxydase (GPOX) et la catalase (CAT), en utilisant l’électrophorèse sur gel de polyacrylamide (PAGE) en conditions natives. Les résultats obtenus montrent une réduction du potentiel osmotique foliaire et une diminution de Chl a+b et Car sous l’effet du stress hydrique. Toutefois, il existe des différences significatives entre les génotypes étudiés en réponse au traitement imposé. PAGE a permis de montrer une augmentation dans l’intensité des enzymes étudiées et une apparition d’isoformes supplémentaires, dont une de CAT et trois de SOD, en conditions de stress. Ces différences dans les réponses au stress hydrique pourraient être des indices utiles et fiables pour la sélection de génotypes tolérants de blé dur.Osmotic adjustment, photosynthetic pigments and changes in antioxidant enzyme activities were evaluated in ten durum wheat (Triticum durum) genotypes under water stress conditions. The wheat seedlings germinated in hydroponic conditions in a growth chamber. Water deficit was performed at the fourth and fifth leaf stages using a polyethylene glycol (PEG 6000) solution (-0.49 MPa). Osmotic potential as well as total chlorophyll (Chl a+b) and carotenoid (Car) contents were investigated. Electrophoretic analyses were performed for three antioxidant enzymes: superoxide dismutase (SOD), guaiacol peroxidase (GPOX) and catalase (CAT) using native polyacrylamide gel electrophoresis (PAGE). The results obtained show a reduction in leaf osmotic potential and a decrease in Chl a+b and Car contents under water stress conditions. However, there are significant differences between the genotypes studied in their response to the treatment. PAGE showed an increased intensity in the enzymes studied and the appearance of additional isoforms, including one CAT and three SOD, under stress conditions. These differences in water stress response could be useful and reliable indices for the selection of tolerant durum wheat genotypes