Banana (Musa spp.) is an important staple food as well as cash crop in tropical and subtropical countries. Various bacterial, fungal, and viral diseases and pests such as nematodes are major constraints in its production and are currently destabilizing the banana production in sub-Saharan Africa. Genetic engineering is a complementary option used for incorporating useful traits in banana to bypass the long generation time, polyploidy, and sterility of most of the cultivated varieties. A robust transformation protocol for farmer preferred varieties is crucial for banana genomics and improvement. A robust and reproducible system for genetic transformation of banana using embryogenic cell suspensions (ECS) has been developed in this study. Two different types of explants (immature male flowers and multiple buds) were tested for their ability to develop ECS in several varieties of banana locally grown in Africa. ECS of banana varieties “Cavendish Williams” and “Gros Michel” were developed using multiple buds, whereas ECS of “Sukali Ndiizi” was developed using immature male flowers. Regeneration efficiency of ECS was about 20,000–50,000 plantlets per ml of settled cell volume (SCV) depending on variety. ECS of three different varieties were transformed through Agrobacterium-mediated transformation using gusA reporter gene and 20–70 independent transgenic events per ml SCV of ECS were regenerated on selective medium. The presence and integration of gusA gene in transgenic plants was confirmed by PCR, dot blot, and Southern blot analysis and expression by histochemical GUS assays. The robust transformation platform was successfully used to generate hundreds of transgenic lines with disease resistance. Such a platform will facilitate the transfer of technologies to national agricultural research systems (NARS) in Africa.

Background Trypanosoma brucei, the causative agent of Human African Trypanosomiasis (HAT), expresses two proteins with homology to human glycogen synthase kinase 3β (HsGSK-3) designated TbruGSK-3 short and TbruGSK-3 long. TbruGSK-3 short has previously been validated as a potential drug target and since this enzyme has also been pursued as a human drug target, a large number of inhibitors are available for screening against the parasite enzyme. A collaborative industrial/academic partnership facilitated by the World Health Organisation Tropical Diseases Research division (WHO TDR) was initiated to stimulate research aimed at identifying new drugs for treating HAT.Methodology/Principal FindingsA subset of over 16,000 inhibitors of HsGSK-3 β from the Pfizer compound collection was screened against the shorter of two orthologues of TbruGSK-3. The resulting active compounds were tested for selectivity versus HsGSK-3β and a panel of human kinases, as well as in vitro anti-trypanosomal activity. Structural analysis of the human and trypanosomal enzymes was also performed.Conclusions/SignificanceWe identified potent and selective compounds representing potential attractive starting points for a drug discovery program. Structural analysis of the human and trypanosomal enzymes also revealed hypotheses for further improving selectivity of the compounds.

A reproducible regeneration protocol for ICGV 12991, CG 7 and Red Valencia groundnut genotypes using Cotyledonary Node explants has been optimized. The effect of different BAP concentrations combined with either 2,4-D or TDZ was tested to determine optimum conditions for high shoot induction. Different BAP concentrations were tested to determine an optimum concentration for shoot elongation. Different NAA concentrations were similarly evaluated to determine the best concentration for rooting. Media containing combination of 5 mg/L BAP and 1 mg/L TDZ was the best concentration for shoot induction while media containing BAP at 5 mg/L was the best for elongation of shoots. NAA concentration of 1 mg/L gave the highest number of plants with roots. This works provides a very good protocol which will be beneficial during groundnut tissue culture as well as genetic transformation of groundnuts.

Drought is the most perilous abiotic stress that affects finger millet growth and productivity worldwide. For the successful production of finger millet, selection of drought tolerant varieties is necessary and critical stages under drought stress, germination and early seedling growth, ought to be fully understood. This study investigated the physiological and biochemical responses of six finger millet varieties (GBK043137, GBK043128, GBK043124, GBK043122, GBK043094 and GBK043050) under mannitol-induced drought stress. Seeds were germinated in sterile soil and irrigated with various concentrations of mannitol (200, 400 and 600 mM) for 2 weeks. In a comparative analysis relative water content (RWC), chlorophyll, proline and malondialdehyde (MDA) contents were measured to obtain the physiological and biochemical characteristics of drought stress. The results showed that increased levels of drought stress seriously decreased germination and early seedling growth of finger millet varieties. However, root growth was increased. In addition, exposition to drought stress triggered a significant decrease in relative water content and chlorophyll content reduction, and the biochemical parameters assay showed less reduction in RWC. Furthermore, oxidative damage indicating parameters, such as proline concentration and MDA content, increased. Varieties GBK043137 and GBK043094 were less affected by drought than the other varieties as shown by significant changes in their physiological parameters. Our findings reveal the differences between the physiological and biochemical responses of finger millet to drought and are vital for breeding and selecting drought tolerant varieties of finger millet. Further, genomic and molecular investigations need to be undertaken to gain a deeper insight into the detailed mechanisms of drought tolerance in finger millet.

Sweetpotato is a significant crop which is widely cultivated particularly in the developing countries with high and stable yield. However, drought stress is a major limiting factor that antagonistically influences the crop's productivity. Dehydration stress caused by drought causes aggregation of reactive oxygen species (ROS) in plants, and aldose reductases are first-line safeguards against ROS caused by oxidative stress. In the present study, we generated transgenic sweetpotato plants expressing aldose reductase, XvAld1 isolated from Xerophyta viscosa under the control of a stress-inducible promoter via Agrobacterium-mediated transformation. Our results demonstrated that the transgenic sweetpotato lines displayed significant enhanced tolerance to simulated drought stress and enhanced recuperation after rehydration contrasted with wild-type plants. In addition, the transgenic plants exhibited improved photosynthetic efficiency, higher water content and more proline accumulation under dehydration stress conditions compared with wild-type plants. These results demonstrate that exploiting the XvAld1 gene is not only a compelling and attainable way to improve sweetpotato tolerance to drought stresses without causing any phenotypic imperfections but also a promising gene candidate for more extensive crop improvement.