Barend Juan Vorster

• Professor
• Professor (Associate) at University of Pretoria

Amaranthus hybridus L. is a major weed for summer crops. Although A. hybridus has been a known crop weed in the Republic of South Africa (RSA) for a long time, herbcide resistance has not been a problem. Nevertheless, A. hybridus populations from Kwa Zulu Natal (KZN) Province have caught the attention of farmers since glyphosate has been progressiv...

Weeds are attractive models for basic and applied research due to their impacts on agricultural systems and capacity to swiftly adapt in response to anthropogenic selection pressures. Currently, a lack of genomic information precludes research to elucidate the genetic basis of rapid adaptation for important traits like herbicide resistance and stre...

Common bean seeds are an excellent source of protein as well as of carbohydrates, minerals, vitamins, and bioactive compounds reducing, when in the diet, the risks of diseases. The presence of bioactive compounds with antinutritional properties (e.g., phytic acid, lectins, raffinosaccharides, protease inhibitors) limits, however, the bean’s nutriti...

Proteases, including serine proteases, are involved in the entire life cycle of plants. Proteases are controlled by protease inhibitors (PI) to limit any uncontrolled or harmful protease activity. The role of PIs in biotic and abiotic stress tolerance is well documented, however their role in various other plant processes has not been fully elucida...

Palmer amaranth ( Amaranthus palmeri S. Watson) is not native to Africa. Based on the presence and persistence of A. palmeri populations, its invasive status in southern Africa is classified as “naturalized”. Globally, A. palmeri is one of the most troublesome weed species in several crops including soybean [ Glycine max (L.) Merr.], maize ( Zea ma...

In recent decades, scarcity of available resources, population growth and the widening in the consumption of processed foods and of animal origin have made the current food system unsustainable. High-income countries have shifted towards food consumption patterns which is causing an increasingly process of environmental degradation and depletion of...

The International Weed Genomics Consortium is a collaborative group of researchers focused on developing genomic resources for the study of weedy plants. Weeds are attractive systems for basic and applied research due to their impacts on agricultural systems and capacity to swiftly adapt in response to anthropogenic selection pressures. Our goal is...

Six Conyza bonariensis (L.) Cronquist populations were screened in a pot experiment at the University of Pretoria's Hatfield experimental farm to evaluate and confirm the degree of glypho-sate response. Resistance factors ranged from 2.7-to 24.8-fold compared to the most susceptible biotype. Partial sequencing of the 5-enolpyruvylshikimate-3-phosph...

Abstract Recent focus on indigenous knowledge of plant species that have long been consumed by mankind, but not having a prominent place in organized agriculture, has raised the profile of what steps are needed to bring such potentially useful plant species into formal agriculture practice. Many of these orphan plants have been cultivated, albeit u...

The hypersensitive response is elicited by Agrobacterium infiltration of Nicotiana benthamiana, including the induction and accumulation of pathogenesis-related proteins, such as proteases. This includes the induction of the expression of several cysteine proteases from the C1 (papain-like cysteine protease) and C13 (legumain-like cysteine protease...

Global climate change, causing large parts of the world to become drier with longer drought periods, severely affects production of common beans (Phaseolus vulgaris L.). The bean is worldwide the most produced and consumed food grain legume in the human diet. In common beans, adapted to moderate climates, exposure to drought/heat stress not only re...

Protein engineering approaches have been proposed to improve the inhibitory properties of plant cystatins against herbivorous arthropod digestive proteases, generally involving the site‐directed mutagenesis of functionally relevant amino acids or the selection of improved inhibitor variants by phage display approaches. Here, we propose a novel appr...

South African soils generally lack native Bradyrhizobium strains that nodulate and fix atmospheric nitrogen (N2) in soybeans (Glycine max L.). It is therefore very important to inoculate soybeans with products that contain effective Bradyrhizobium strains as active ingredients. In this study, a field experiment was conducted on two bioclimatic zone...

Citation: Gatabazi, A.; Vorster, B.J.; Mvondo-She, M.A.; Mangwende, E.; Mangani, R.; Hassen, A.I. Efficacy of Peat and Liquid Inoculant Formulations of Bradyrhizobium japonicum Strain WB74 on Growth, Yield and Nitrogen Concentration of Soybean (Glycine max L.). Nitrogen 2021, 2, 332-346. https://doi.

Protein engineering approaches have been proposed to improve the inhibitory properties of plant cystatins against herbivorous arthropod digestive proteases. These approaches typically involve the site-directed mutagenesis of functionally relevant amino acids, the production and selection of improved inhibitory variants by molecular phage display pr...

Amaranthus palmeri is native to Mexico and the southeastern parts of the USA, and is reported as alien in subtropical regions of the Old World. Previous records from Africa were from the northern parts of the continent. This species was first found in South Africa in March 2018 with further records in different regions of the country as well as in...

International scientific partnerships are key to the success of strategic investments in plant science research and the farm-level adoption of new varieties and technologies, as well as the coherence of agricultural policies across borders to address global challenges. Such partnerships result not only in a greater impact of published research enha...

Broadly neutralising antibodies (bNAbs) against human immunodeficiency virus type 1 (HIV-1), such as CAP256-VRC26 are being developed for HIV prevention and treatment. These Abs carry a unique but crucial post-translational modification (PTM), namely O-sulfated tyrosine in the heavy chain complementarity determining region (CDR) H3 loop. Several st...

This article comments on: Ye H, Song L, Schapaugh WT, Ali MDL, Sinclair TR, Riar MK, Raymond RN, Li Y, Vuong T, Valliyodan B, Neto PA, Klepadlo M, Song Q, Shannon JG, Chen P, Nguyen HT. 2019. The importance of slow canopy wilting in drought tolerance in soybean, Journal of Experimental Botany 71, 642–652.

Moringa oleifera Lam. is becoming increasingly popular as an industrial crop due to its multitude of useful attributes as a water purifier, nutritional supplement and biofuel feedstock. Horticultural practices such as pruning that encourage improved production of M. oleifera in terms of flowers and fruits have been given little attention especially...

The most important chemicals common in Moringa oleifera Lam. leaves are polyphenols and tannins. They are synthesised during development and the amount and composition are primarily dependent on environmental conditions and factors such as leaf harvesting. Trials were conducted in the Gauteng Province at the University of Pretoria Experimental Farm...

Sclerotinia sclerotiorum (Lib.) de Barry, causal agent of Sclerotinia stem rot of soybeans, is one of the pathogens that could have a potentially devastating impact on the growth of the soybean industry in South Africa. Several quantitative trait loci (QTLs) that play a role in soybean resistance to Sclerotinia stem rot have been identifed and mapp...

Biological nitrogen fixation is an important attribute of legumes. The activity and lifespan of root nodules are however negatively affected by drought stress. Understanding nodule development and senescence is key in developing drought tolerant cultivars. Plant cysteine proteases of the C1 (papain-like) and C13 (legumain-like) families play key ro...

The symbiotic interaction between soybean plants and rhizobacteria can be severely affected by drought, which results in a reduction in symbiotic nitrogen fixation and ultimately decreased yields. The aim of our research was to determine whether symbiotically efficient rhizobia that can better tolerate soil water deficits can improve nodule perform...

Plant proteomes contain hundreds of proteases divided into different families based on evolutionary and functional relationship. In particular, plant cysteine proteases of the C1 (papain-like) and C13 (legumain-like) families play key roles in many physiological processes. The legumain-like proteases, also called vacuolar processing enzymes (VPEs),...

Advances have been recently made in the breeding and characterization of three major legume crops of the semiarid tropics, chickpea, pigeon pea, and groundnut. However, other wild-growing legumes, called "orphan legumes," with potential as crops, but are not yet cultivated would benefit from further attention. This review considers the domesticatio...

Advances have been recently made in the breeding and characterization of three major legume crops of the semiarid tropics, chickpea, pigeon pea, and groundnut. However, other wild‐growing legumes, called “orphan legumes,” with potential as crops, but are not yet cultivated would benefit from further attention. This review considers the domesticatio...

Edited by PN Hills Glyphosate, currently the world's most extensively used herbicide was on the market for more than 20 years since its introduction in 1975 without reported evolution of resistant weed cases. Glyphosate is the only reported herbicide to inhibit 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), and endogenous accumulation of shik...

There have been increased interest to propagate Moringa oleifera because of its multipurpose uses. However there are still no appropriate guidelines for long-term storage of Moringa seed because diverse results are reported in literature. Although progress has been made to understand the causes of seed deterioration, few studies have been made on n...

Plants have developed morphological, physiological, biochemical, cellular, and molecular mechanisms to survive in drought-stricken environments with little or no water caused by below-average precipitation. In this mini-review, we highlight the characteristics that allows marama bean [Tylosema esculentum (Burchell) Schreiber], an example of an orph...

The formation and lifespan of soybean root nodules is affected by drought-stress, compromising the nitrogen supply of soybean plants. Expression of nodule cysteine proteases, involved in the regulation of the bacterial symbiosis and leghemoglobin degradation, increases during nodule senescence. Changes in the root nodule transcriptome were studied...

Termites host a gut microbiota of diverse and essential symbionts that enable specialization on dead plant material; an abundant, but nutritionally imbalanced food source. To supplement the severe shortage of dietary nitrogen (N), some termite species make use of diazotrophic bacteria to fix atmospheric nitrogen (N2). Fungus-growing termites (subfa...

The United Nations declared 2016 as the International Year of Pulses (grain legumes) under the banner ‘nutritious seeds for a sustainable future’. A second green revolution is required to ensure food and nutritional security in the face of global climate change. Grain legumes provide an unparalleled solution to this problem because of their inheren...

There is a growing interest in applying tobacco agroinfiltration for recombinant protein production in a plant based system. However, in such a system, the action of proteases might compromise recombinant protein production. Protease sensitivity of model recombinant foot-and-mouth disease (FMD) virus P1-polyprotein (P1) and VP1 (viral capsid protei...

Drought is considered to be a major threat to soybean production worldwide and yet our current understanding of the effects of drought on soybean productively is largely based on studies on above-ground traits. Although the roots and root nodules are important sensors of drought, the responses of these crucial organs and their drought tolerance fea...

Pre-breeding information on the inheritance mechanism of important sweetpotato (Ipomoea batatas L.) agronomic traits is still limited. This study aimed at assessing the inheritance of five sweetpotato agronomic traits, viz. marketable fresh root yield (MFRY) and number (MNR), total fresh root yield (TFRY) and number (TNR) and root b-carotene conten...

The use of plants as expression hosts for recombinant proteins is an increasingly attractive option for the production of complex and challenging biopharmaceuticals. Tools are needed at present to marry recent developments in high-yielding gene vectors for heterologous expression with routine protein purification techniques. In this study, we desig...

Rice is an emerging food and cash crop in Eastern Africa. Thousands of germplasm accessions have been introduced from major rice breeding centers, such as the International Rice Research Institute (IRRI), and Africa Rice but the genetic variability among the introduced rice germplasm is unknown. Knowledge on genetic diversity would be useful in des...

Phytocystatins are a well-characterized class of naturally occurring protease inhibitors that function by preventing the catalysis of papain-like cysteine proteases. The action of cystatins in biotic stress resistance has been studied intensively, but relatively little is known about their functions in plant growth and defence responses to abiotic...

Background Nodules play an important role in fixing atmospheric nitrogen for soybean growth. Premature senescence of nodules can negatively impact on nitrogen availability for plant growth and, as such, we need a better understanding of nodule development and senescence. Cysteine proteases are known to play a role in nodule senescence, but knowledg...

Almost all protease families have been associated with plant development, particularly senescence, which is the final developmental stage of every organ before cell death. Proteolysis remobilizes and recycles nitrogen from senescent organs that is required, for example, seed development. Senescence-associated expression of proteases has recently be...

This study was done to identify random amplified polymorphic DNA (RAPD) markers that may associate with seven important traits in tea. Sixty RAPD primers were first screened using 18 cultivars under each of the 7 traits, followed by confirmatory screening of 20 promising primers with 32 tea cultivars. Six RAPD primers generated a total of nine spec...

Plants are increasingly used as alternative expression hosts for the production of recombinant proteins offering many advantages including higher biomass and the ability to perform post-translational modifications on complex proteins. Key challenges for optimized accumulation of recombinant proteins in a plant system still remain, including endogen...

Bacterial expression systems are one of the most effective expression systems for producing commercially important proteins due to low cost, high expression levels and well defined purification procedures. However, due to certain limitations, such as the inability to perform post-translational modifications and the exposure of heterologous protein(...

Herbivorous Coleoptera, such as the Colorado potato beetle (CPB) (Leptinotarsa decemlineata Say), compensate to dietary protease inhibitors in plant tissues via a multicomponent defensive strategy involving the overexpression of inhibitor-insensitive proteases. Nearly 40 digestive Cys digestive proteases have been identified in the CPB, belonging t...

Recent research has shown the possibility of tailoring the inhibitory specificity of plant cystatins towards cysteine (Cys) proteases by single mutations at positively selected amino acid sites. Here we devised a cystatin activity-based profiling approach to assess the impact of such mutations at the proteome scale using single variants of tomato c...

Plants are an effective and inexpensive host for the production of commercially interesting heterologous recombinant proteins. The Escherichia coli-derived glutathione reductase was transiently expressed as a recombinant model protein in the cytosol of tobacco plants using the technique of leaf agro-infiltration. Proteolytic cysteine protease activ...

Preparing students for future entrepreneurial activity in the biotechnology industry is an important issue in many parts of the world because most countries seek to reap the benefits of investments in university-based teaching and research through the development of a knowledge-based economy driven by a highly skilled work force 1,2. The current ge...

Seeds from an inbred Vigna unguiculata (cowpea) cultivar were gamma-irradiated with a dose of 180 Gy in order to identify and characterize possible mutations. Three techniques, ie, random amplified polymorphic DNA, microsatellites, and representational difference analysis, were used to characterize possible DNA variation among the mutants and nonir...

Export Date: 12 February 2013, Source: Scopus

Herbivorous Coleoptera, including the Colorado potato beetle, compensate to dietary protease inhibitors in plant tissues through a multicomponent defensive strategy involving the overexpression of inhibitor-sensitive digestive proteases, the expression of proteases insensitive to the inhibitors, and proteolytic inactivation of the inhibitory protei...

Plant cystatins have been the object of intense research since the publication of a first paper reporting their existence more than 20 years ago. These ubiquitous inhibitors of Cys proteases play several important roles in plants, from the control of various physiological and cellular processes in planta to the inhibition of exogenous Cys proteases...

Protease inhibitors are a promising complement to Bt toxins for the development of insect-resistant transgenic crops, but their limited specificity against proteolytic enzymes and the ubiquity of protease-dependent processes in living organisms raise questions about their eventual non-target effects in agroecosystems. After a brief overview of the...

Plant cell systems can be used as an efficient expression system for recombinant proteins. Protein yield however, is severely limited by endogenous degradation through plant proteases. We investigated the VP1 structural protein from the foot-and-mouth disease virus as a model for plant-based recombinant protein production with the co-expression of...

The general potential of plant cystatins for the development of insect-resistant transgenic plants still remains to be established given the natural ability of several insects to compensate for the loss of digestive cysteine protease activities. Here we assessed the potential of cystatins for the development of banana lines resistant to the banana...

Recombinant protease inhibitors represent useful tools for the development of insect-resistant transgenic crops, but questions have been raised in recent years about the impact of these proteins on endogenous proteases and chemical composition of derived food products. In this study, we performed a detailed compositional analysis of tubers from pot...

The presence of chloroplast-related DNA sequences in the nuclear genome is generally regarded as a relic of the process by which genes have been transferred from the chloroplast to the nucleus. The remaining chloroplast encoded genes are not identical across the plant kingdom indicating an ongoing transfer of genes from the organelle to the nucleus...

Representational difference analysis was applied to subtract the genomes of the two date palm varieties, Barhee and Medjool, for identification and characterization of unique genome differences suitable for discriminating between individual plants and the two varieties. Three different DNA difference products were isolated from Barhee representing...

Any company involved in micropropagation of plants must be able to demonstrate that the plants produced remain true-to-type as an important part of quality assurance. Modern approaches to detect undesired plant off-types in the in vitro propagation process might also include the application of the "DNA-microchip" technology using DNA microarrays ca...