Agrobacterium-mediated barley transformation.

More than ten years have passed since the first successful Agrobacterium-mediated barley transformation experiment, however it is still quite challenging to establish a stably functioning agroinfiltration protocol. Efficiency of the method depends mainly on the transformation and co-cultivation conditions, and also the components of the tissue-culture media. With the use of an optimized media we have been able to set up a reliable, properly functioning transformation protocol. The first generation of transgenic barley plants, transformed with a transformation cassette carrying an aldo-keto-reductase gene from Arabidopsis thaliana and the hpt marker gene, were analyzed at nucleic acid (both DNA and RNA) and at protein levels. The key factors of success proved to be the use of Silwet L-77 (surfactant) in transformation inoculum, the Cu-content of regenerating media and the continuous visual monitoring of the transformed callus during the somatic embryogenesi

TRAUCO, a Trithorax-group gene homologue, is required for early embryogenesis in Arabidopsis thaliana

Embryogenesis is a critical stage during the plant life cycle in which a unicellular zygote develops into a multicellular organism. Co-ordinated gene expression is thus necessary for proper embryo development. Polycomb and Trithorax group genes are members of evolutionarily conserved machinery that maintains the correct expression patterns of key developmental regulators by repressing and activating gene transcription. TRAUCO (TRO), a gene homologous to the Trithorax group of genes that can functionally complement a BRE2P yeast mutant, has been identified in Arabidopsis thaliana. It is demonstrated that TRO is a nuclear gene product expressed during embryogenesis, and loss of TRO function leads to impaired early embryo development. Embryos that arrested at the globular stage in the tro-1 mutant allele were fully rescued by a TRO expression clone, a demonstration that the tro-1 mutation is a true loss-of-function in TRO. Our data have established that TRO is the first trithorax-group gene homologue in plants that is required for early embryogenesi

Cryoconservation d'embryons somatiques de palmier à huile (Elaeis guineensis Jacq.) : Résultats et perspectives d'application

La cryoconservation de jeunes embryoïdes de palmier à huile est réalisée en utilisant une vitesse de congélation rapide (200¼C min-1). Les taux de survie obtenus varient de 50 à 80 p. 100 et l'embryogenèse adventive reprend sur 10 à 20 p. 100 des massifs congelés. Après le traitement rhizogène des pousses feuillées issues des embryoïdes congelés, les vitroplants sont acclimatés en serre et leur développement s'effectue normalement jusqu'à présent. L'utilisation d'un congélateur programmable pour la congélation des massifs d'embryoïdes, qui permet d'obtenir des vitesses de refroidissement plus précises et parfaitement reproductibles, conduit aux mêmes résultats. La reprise de l'embryogenèse adventive a été observée sur des massifs d'embryoïdes stockés respectivement 7 et 15 mois dans l'azote liquide. Ces résultats permettent d'envisager l'application rapide de cette technique de cryoconservation pour le stockage des lignées d'embryoïdes produits par la culture in vitro et son extension par la suite à la conservation des ressources génétiques du palmier à huil

Morphological and Physiological Abnormalities in Tissue Culture-Derived Date Palm (Phoenix dactylifera L.) Plants

The UAE attaches great importance to agricultural development with a sound focus on date palms. This special attention is obvious in the ongoing expansion of agricultural resources and investments, the growing number of palm trees, and in the extensive use of modern technologies. Mass cultivation of date palm trees is required to continue according to the country\u27s agricultural plans. In order to achieve these agricultural expansion of date palm, new techniques of propagation other than traditional techniques (seed and offshoot propagation) are critically required. Tissue culture is a modern and reliable technology being one of the main methods for date palm propagation. However, such technique seems to be expensive and has a few problems that still need to be studied carefully. Trueness-to-type and appearance of abnormalities are the most serious problems associated with the tissue culture derived plants. These problems can be solved and perhaps eliminated by further study on developing the conditions used in this technique. The aim of the present investigation is to study the morphological abnormalities in tissue culture-derived date palm plants and to relate these abnormalities to the applied conditions during the in vitro multiplication process. These results will contribute to avoiding such shortcomings in the future and avoid the occurrence and propagation of such abnormalities

Effects of sucrose and methylglyoxal bis-(guanylhydrazone) on controlling grape somatic embryogenesis

The effects of sucrose and methylglyoxal bis-(guanylhydrazone) (MGBG) on grape (Vitis vinifera L. cv. Thompson Seedless) somatic embryogenesis was examined by subculturing somatic embryos and embryogenic cells monthly to embryo maintenance medium (MMS) containing 60, 90, 120, 150, or 180 g/l sucrose; or 0, 0.1, 1, or 10 mM MGBG for three months. The growth and development of grape embryogenic cultures was inhibited by incubating them on MMS with 150 or 180 g/l sucrose compared to 60, 90, or 120 g/l. Culture dry weight was significantly greater for embryogenic cells grown on MMS with 90 or 120 g/l sucrose compared with those reared on standard MMS (60 g/l sucrose), indicating that embryogenic cells grew better on MMS with 90 or 120 g/l sucrose and were less hydrated. The number of cotyledonary-stage somatic embryos that resembled zygotic embryos was improved 10.8- to 21.3-fold by incubating grape embryogenic cells on MMS with 90 or 120 g/l sucrose, respectively. Germination-and plant development of grape somatic embryos was improved following incubation on MMS with 150 g/l sucrose before transfer to germination medium with benzyladenine. However, fewer embryos were produced on this medium compared to all other sucrose levels, suggesting that maintaining embryogenic cultures on MMS with 120 g/l sucrose followed by one transfer onto MMS with 150 g/l sucrose may improve embryo development and plant regeneration. MGBG at 1 to 10 mh I inhibited the growth and development of grape embryogenic cultures. Exposure of embryogenic cells to 10 mM MGBG inhibited their growth and development through the course of the experiment and caused their death by the third month of culture. In contrast, a 3-month exposure was required to inhibit embryo growth in the presence of 1 mM MGBG. Addition of MGBG to MMS did not improve embryo quality or plant development

Differential Gene Expression Analysis of Zebrafish Embryos Exposed to Simulated Microgravity and Insights into Cellular Effects

Spaceflight consists of many dangers which adversely affects the health of astronauts through hazards such as microgravity and cosmic radiation. One area that is still poorly understood is how spaceflight impacts human reproductive health. This study aims to shed insight into how microgravity may impact the development of embryos. Differential gene expression analysis was performed via Jupyter Notebook and SLURM scripts and run on SJSU’s HPC server as a method of implementing NASA GeneLab’s RNA-Seq Consensus Pipeline. Data for this project utilized RNA-Seq files for early-stage embryonic zebrafish (Danio rerio), stored under GLDS-373. Gene Set Enrichment Analysis was performed to gain a clearer understanding of which types of genes are impacted by microgravity, and to provide greater statistical significance to the differential gene expression results. The findings in this study found that there was a relationship between microgravity and upregulation in genes related to cell proliferation, differentiation, and development. However more studies are required before a mechanism can be identified to explain these observations and risks mitigated for future astronauts and their children. Keywords: Differential gene expression, gene enrichment analysis, microgravity, embryogenesi