Building a bi-directional promoter binary vector from the intergenic region of Arabidopsis thaliana cab1 and cab2 divergent genes useful for plant transformation

The ability to express genes in a controlled and limited domain is essential to succeed in targeted genetic modification. Having tools by which to rapidly and conveniently generate constructs which can be assayed in a diverse array of plant species expedites research and end-product development. Targeting specifically green plant tissues offers an opportunity to effect changes to diverse processes such as water use efficiency, photosynthesis, predation and nutrition. To facilitate the generation of transgenes to be expressed in this domain, we created a series of plasmids called p2CABA based on the Arabidopsis thaliana chlorophyll a/b gene promoter, a single natural bidirectional promoter that can drive and express two different genes at the same time. Studies we carried out showed reporter gene, GUS expressed in leaves and stems but not in the roots, as expected since this endogenous promoter controls the expression of two photosynthetic genes in A. thaliana. We, therefore, utilized the intergenic region between the A. thaliana cab1 and cab2 divergent genes to design and construct a bidirectional promoter vector containing two multiple cloning sites and a gateway recombination cassette. This in turn will help minimize gene silencing and achieve desirable expression pattern of transgenes, a critical issue in plant genetic engineering and in this report we show their use in Medicago and tomato.Key words: Arabidopsis cab genes, bidirectional promoters, gene expression, plant genetic engineering, reporter genes, photosynthetic genes

Characteristics and changes in SON rainfall over Uganda (1901-2013)

This study investigated the characteristics and changes in September-November (SON) rainfall over Uganda. The dominant mode of variability of SON rainfall was identified by performing Empirical orthogonal functions (EOF) analysis, using rainfall data from Climate Research Unit (CRU) for the period 1901 to 2013. Results indicate that the dominant mode of variability of SON rainfall exhibits a unimodal pattern, explaining 50.2% of the total variance. Mann-Kendall analysis was deployed to examine sudden changes in SON rainfall over the country. The findings show that the abrupt change in SON rainfall occurred in 1994. Further analysis reveal that SON rainfall over Uganda has a correlation pattern with the sea surface temperature (SST) over Indian, which depicts the positive phase of the Indian Ocean Dipole (IOD). Positive correlation is exhibited in the western IOD subregion, while negative correlation is shown in the southeastern IOD sub-region. Further study of the both driest and wettest years during the investigated time span indicate that throughout the wettest year, there were positive anomalies in the western sub-region, contrary to the driest year, when same subregion observed distinct negative anomalies. This illustrates that the positive phase of IOD enhances SON rainfall over Uganda, as opposed to the negative phase which inhibits SON rainfall. The evolution of the IOD can therefore be monitored for the improvement of SON rainfall forecasts, especially over Uganda so as to avoid the losses associated with weather extremes

'NABIO808' (Syn. 'NAROBAN5'): A tasty cooking banana cultivar with resistance to pests and diseases

Abstract 'NABIO808' is a newly released, conventionally-bred triploid cooking banana cultivar in Uganda. It produces an average bunch yield of 54.5 t ha-1 yr-1 and is resistant to weevils, nematodes, and black Sigatoka. Additionally, its food is yellow, soft, and tasty, like that of most preferred landrace cultivars, making it more acceptable to end-users

Studies of generic and specific delimitation of the genera Drimiopsis and Ledebouria (Hyacinthaceae)

The monocot genera Ledebouria and Drimiopsis belong to the family Hyacinthaceae in the order Asparagales. The aim of this study was to investigate the generic delimitation between the two genera using DNA sequencing, and to investigate the specific delimitation within Ledebouria using both morphological and molecular characters. For the molecular analysis the Drimiopsis and Ledebouria specimens were sequenced for three chloroplast regions; trnL intron, trnL-F intergenic spacer and trnS-G intergenic spacer. In the strict consensus tree of the combined analysis of the three regions, the two genera each form a monophyletic group (though without any bootstrap or jackknife support), supporting the recognition of two separate genera. For the morphological investigation 22 Ledebouria specimens were investigated using univariate and multivariate analyses of altogether 19 qualitative and quantitative characters. The analyses of the morphological data provided not enough information for the proposal of a final specific delimitation within Ledebouria, but together with the molecular phylogeny they suggested that six tentative taxa may be identified within the genus Ledebouria; L. kirkii, two groups of broad leaved taxa (L. cordifolia and one unnamed taxon), and three groups within the L. revoluta complex. The characters leaf width, leaf length, perianth segment length, leaf threads, spotting pattern of the leaves and ovary shape seem to be the most important morphological characters for delimiting these taxa. However, more investigations (morphological and molecular) including more specimens from all geographical regions is needed to confirm this result. Keywords; Drimiopsis, Ledebouria, morphology, DNA sequencing, generic and specific delimitation

Pro-vitamin A biofortified 'Cavendish' banana: Trait stability in the field

Vitamin A deficiency (VAD) is a major public health problem in the developing world affecting an estimated 250 million people worldwide. The majority of these people live in developing countries and are dependent on starchy staples such as cassava, maize, potato, rice and banana which are largely deficient in critical micronutrient such as pro-vitamin A. The research in this PhD Thesis demonstrates that pro-vitamin carotenoid content can be enhanced in the fruit of genetically modified 'Cavendish' banana plants through the over-expression of a single banana gene. Importantly, the newly conferred trait was stable for several years in the field and the expression of other endogenous carotenoid biosynthesis genes remained unchanged. This research provides important background information for the successful expansion of this technology to Uganda where bananas are the major staple

The potential of in-situ hyperspectral remote sensing for differentiating 12 banana genotypes grown in Uganda

Bananas and plantains provide food and income for more than 50 million smallholder farmers in East and Central African (ECA) countries. However, banana productivity generally achieves less than optimal yield potential

Techniques for measuring dynamic tire forces generated by heavy vehicles

Summary\ud \ud Vitamin A deficiency remains one of the world's major public health problems despite food fortification and supplements strategies. Biofortification of staple crops with enhanced levels of pro-vitamin A (PVA) offers a sustainable alternative strategy to both food fortification and supplementation. As a proof of concept, PVA-biofortified transgenic Cavendish bananas were generated and field trialed in Australia with the aim of achieving a target level of 20 μg/g of dry weight (dw) β-carotene equivalent (β-CE) in the fruit. Expression of a Fe'i banana-derived phytoene synthase 2a (MtPsy2a) gene resulted in the generation of lines with PVA levels exceeding the target level with one line reaching 55 μg/g dw β-CE. Expression of the maize phytoene synthase 1 (ZmPsy1) gene, used to develop “Golden Rice 2”, also resulted in increased fruit PVA levels although many lines displayed undesirable phenotypes. Constitutive expression of either transgene with the maize polyubiquitin promoter increased PVA accumulation from the earliest stage of fruit development. In contrast, PVA accumulation was restricted to the late stages of fruit development when either the banana 1-aminocyclopropane-1-carboxylate oxidase or the expansin 1 promoters were used to drive the same transgenes. Wild-type plants with the longest fruit development time had also the highest fruit PVA concentrations. The results from this study suggest that early activation of the rate-limiting enzyme in the carotenoid biosynthetic pathway, as well as extended fruit maturation time, are essential factors to achieve optimal PVA concentrations in banana fruit