Direct genetic transformation of Hibiscus sabdariffa L.

Transgenic Hibiscus sabdariffa plants have been produced by a tissue culture independent method using Agrobacterium tumefasciens transformation procedure. Embryo axes of mature seeds with one cotyledon excised were infected by immersion in a suspension of Agrobacterium LBA 4404 strain culture that carries pBal plasmid with β-glucuronidase p35SGUSINT and plant selectable marker Neomycin Phospho-Transferase gene (nptII). Following a 24 h co-cultivation with Agrobacterium strain and decontamination with cefotaxime, embryos were grown on soil rite containing MS medium added with a killer concentration of kanamycin (100 μg/ml) during 4 weeks at room conditions and thereafter transferred to greenhouse. 54.3% of the seedlings grew well on the selective medium; 68% of the explants excised from putative transformed plants were found to be GUS positive. After 60 days evaluation point, the assessment of the transformation by PCR revealed that H. sabdariffa line tested, carried the nptII gene. Key Words: Hibiscus sabdariffa; genetic transformation. African Journal of Biotechnology Vol. 3 (4), 2004: 226-22

Screening cowpea [Vigna unguiculata (L.) Walp.] varieties by inducing water deficit and RAPD analyses

The effects of water deficit induced by polyethylene glycol-6000 on some cowpea varieties, which belong to the national germplasm in Senegal are reported. Our results showed that, the length of the epicotyl was not affected by water deficit but the length of primary root was influenced only in Mouride variety. Water deficit influenced mostly the number of lateral roots. The 985 variety showed a great increase of its lateral root numbers and could be considered a drought tolerant variety. In contrast, the IT81D-1137 variety is very sensitive to water deficit because its lateral root number were reduced 3.8 fold compared to the control. These physiological studies were complemented by analyzing the genetic diversity of these varieties with random amplified polymorphic DNA (RAPD). The RAPD analysis suggested that the samples were also genetically diverse. Key Words: Vigna unguiculata, drought tolerance, PEG, RAPD. African Journal of Biotechnology Vol.3(3) 2004: 174-17

Influence of Growth Regulators on Callogenesis and Somatic Embryo Development in Date Palm (Phoenix dactylifera L.) Sahelian Cultivars

This study provides a physiological analysis of somatic embryogenesis in four elite cultivars of date palms: Ahmar, Amsekhsi, Tijib, and Amaside, from the initial callogenesis to establishment and proliferation of embryogenic suspension cultures. Somatic embryos development and in vitro plants rooting were also studied. For each step, auxins and cytokinins concentrations were optimised. The primary callogenesis from leaf explants of seedlings appeared highly dependent on genotype. Ahmar (80%) and Amsekhsi (76%) appeared highly callogenic, whereas Tijib (10%) and Amaside (2%) produced low amounts of calluses. 2,4-Dichlorophenoxyacetic acid appeared favorable to the induction of primary callogenesis and its effect was enhanced by the addition of benzyl adenine or adenine sulfate. Secondary friable calli obtained from chopped granular calli were used to initiate embryogenic cell suspensions in media supplied with 2,4-dichlorophenoxyacetic acid. Suspension cultures showed a growth rate of fourfold after four subcultures in presence of 2,4-dichlorophenoxyacetic acid 2 mg/L. Our results showed that a seven-day transitory treatment with benzyl adenine 0,5 mg/L was necessary to optimize embryos development. Naphthalene acetic acid induced the development of primary orthogravitropic roots during embryos germination. The comparison with cytofluorometry of nuclear DNA amounts showed no significant difference in ploidy level between regenerated plants and seedlings

Full Length Research Paper - Direct genetic transformation of Hibiscus sabdariffa L.

Transgenic Hibiscus sabdariffa plants have been produced by a tissue culture independent method using Agrobacterium tumefasciens transformation procedure. Embryo axes of mature seeds with one cotyledon excised were infected by immersion in a suspension of Agrobacterium LBA 4404 strain culture that carries pBal plasmid with b-glucuronidase p35SGUSINT and plant selectable marker Neomycin Phospho-Transferase gene (nptII). Following a 24 h co-cultivation with Agrobacterium strain and decontamination with cefotaxime, embryos were grown on soil rite containing MS medium added with a killer concentration of kanamycin (100 µg/ml) during 4 weeks at room conditions and thereafter transferred to greenhouse. 54.3% of the seedlings grew well on the selective medium; 68% of the explants excised from putative transformed plants were found to be GUS positive. After 60 days evaluation point, the assessment of the transformation by PCR revealed that H. sabdariffa line tested, carried the nptII gene

Induction in vitro de l'enracinement de microboutures d'Acacia tortilis subsp. raddiana par traitement transitoire à l'auxine

Transient auxin treatment for in vitro rooting of microcuttings of Acacia tortilis subsp. raddiana. An auxin in vitro pretreatment (IBA or NAA at 10 to 20 mg L$^{-1}$) combined with a low concentration of Kinetin (0.01 mg L$^{-1}$) during 10 or 20 days allowed to improve the rooting (number and root length) of Acacia tortilis raddiana microcuttings after transfer on Lloyd and Mc Cown medium (WPM) without hormone. After microcuttings transfer in expression medium, 56% are rooted and the rooting frequency can reach 80% after pretreatment with IBA at 10 mg L$^{-1}$. Measurements made after 28 days show that the auxin type used for inducing rhizogenesis has a significant effect, both on rooting percentage and rooting system morphology. For 80% of plantlets, the number of roots is low with NAA (1 to 5) but roots are strong and orthotropic (4.5 to 5 cm on average) when with IBA roots are numerous (10 to 15), but thin and plagiotropic (3 to 3.7 cm) for 68% of rooted plantlets.Chez Acacia tortilis raddiana, l'application transitoire d'auxine (acide indol butyrique (AIB) ou acide naphtalène acétique (ANA) à 10 ou 20 mg L$^{-1}$) combinée ou non avec une cytokinine (kinétine à 0,01 mg L$^{-1}$) pendant 10 ou 20 jours a permis d'améliorer l'enracinement (nombre et longueur moyenne des racines) après le transfert des microboutures sur un milieu Lloyd et McCown (WPM) dépourvu d'hormone. Le pourcentage des microboutures enracinées sur milieu d'expression est de 56 % en moyenne et atteint 80 % avec un traitement inductif à 10 mg L$^{-1}$ d'AIB. Les mesures effectuées après 28 jours de culture ont montré que la nature de l'auxine utilisée pour induire la rhizogenèse a une influence significative aussi bien sur la fréquence de l'enracinement que sur la morphologie du système racinaire qui se met en place. Avec l'ANA les racines sont peu nombreuses (1 à 5 racines par bouture) et robustes et orthotropes (4,5 à 5 cm en moyenne) dans 80 % des cas et avec l'AIB, elles sont très nombreuses (10 à 15 racines par bouture) et fines et plagiotropes (3 à 3,7 cm) dans 68 % des cas