Prof Juan Vorster



Associate Professor

Department

FABI
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Research Profiles

 

I am currently appointed as an Associate Professor in the Department of Plant and Soil Sciences in the Faculty of Natural and Agricultural Sciences.

and have led the Molecular Plant Physiology research group in FABI since 2010. I also lead the molecular research aspects related to herbicide resistance mechanisms in the South African Herbicide Resistance Initiative (SAHRI).

My research focus on plant stress physiology, and in particular, how plants adapt to stress. Sustainable crop production in dryer environments is becoming increasingly important under changing climate conditions. Over the last 10 years, my research group has studied the impact of drought on soybean and its ability to fix nitrogen under drought conditions. This has led to the identification of key genes that regulate development under stress that can be used to select more drought tolerant cultivars. More recently, my research has also included the study of herbicide resistance mechanisms in weeds and the development of effective management strategies to ensure effective and sustainable crop production.

I currently also serve as the president of the South African Society of Crop Production and on the management board of the South African Journal of Plant and Soil.

In the Soybean Research Program we are focused on understanding and improving biological nitrogen fixation in root nodules under drought stress. Over the years we have used transcriptome analysis to develop a profile of gene expression during nodule development and senescence under both optimal as well as drought conditions. We have been particularly interested in how cysteine proteases and cysteine protease inhibitors (cystatins) regulate natural as well as stress-induced senescence. We have identified a specific member of this gene family that is unregulated during the initiation of drought-induced senescence and is evaluating its potential as a marker but also a target to delay senescence in root nodules.

We are also interested in the role that specific Rhizobium strains play in regulating nodule initiation, development and overall biological nitrogen fixation. We are currently testing different species and strains to see how they perform under water-limiting conditions compared to current commercial strains.

In the South African Herbicide Resistance Initiative we are working closely with Industry partners to identify cases of herbicide resistance in South African weed populations and to determine the physiological mechanisms resulting in resistance. This allows us to develop specific management strategies to effectively control these populations. We are also actively involved in farmer outreach to help farmers improve their control programs in cases of herbicide resistance.

 

 

 


I am responsible for teaching the Weed Science component of Crop Protection (PLG 251), Crop Physiology (APS 461 and APS 761) and Weed Science (OKW413 and PPK 712).

 


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Book Chapters
Kunert K, Vorster J, Bester C, Cullis C, Rajasekaran K, Jacks T, Finley J. 2002. DNA microchip technology in the plant tissue culture industry. In: Crop Biotechnology, ACS Symposium Series, Vol. 829. American Chemical Society, USA, pp 86-96.
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Publication
Kunert KJ, Botha A-M, Oberholster PJ, Yocgo R, Chimwamurombe P, Vorster J, Foyer CH. (2020) Factors facilitating sustainable scientific partnerships between developed and developing countries. Outlook on Agriculture 49(3):204-214. 10.1177/0030727020939592 PDF
Singh AA, Tsekoa TL, Morris L, Steinkellner H, Mach L, Whaley K, Zeitlin L, Pauly M, Vorster J, Bhiman JN, Gerber I, Alexandra K, Stoychev SH, Lotter-Stark T, Kwezi L, Pooe O, Chikwamba R. (2020) Plant-based production of highly potent anti-HIV antibodies with engineered posttranslational modifications. Scientific Reports 10:6201. 10.1038/s41598-020-63052-1 PDF
Kunert K, Vorster BJ . (2020) In search for drought-tolerant soybean: is the slow-wilting phenotype more than just a curiosity?. Journal of Experimental Botany 71(2):457-460. 10.1093/jxb/erz235 PDF
Mbedzi PP, Van den Hooven L, Vorster BJ , Van der Waals J. (2019) Screening for Sclerotinia sclerotiorum resistance using detached leaf assays and simple sequence repeat markers in soybean cultivars. Crop Protection 215:104909. 10.1016/j.cropro.2019.104909 PDF
Kibido T, Kunert K, Makgopa M, Greve M, Vorster BJ . (2019) Improvement of rhizobium‐soybean symbiosis and nitrogen fixation under drought. Food and Energy Security :e117. 10.1002/fes3.177 PDF
Juan Vorster, Chris Cullis, Karl Kunert. (2019) Plant Vacuolar Processing Enzymes. Frontiers in Plant Science :00497. 10.3389/fpls.2019.00479 PDF
Cullis C, Lawler DW, Chimwamurombe P, Kunert K, Bbebe N, Vorster J. (2019) Development of marama bean, an orphan legume, as a crop. Food and Energy Security e00164:1-12. 10.1002/fes3.164 PDF
NM Okumu, BJ Vorster, CF Reinhardt. (2019) Growth-stage and temperature influence glyphosate resistance in Conyza bonariensis (L.) Cronquist.. South African Journal of Botany 121:248-256. 10.1016/j.sajb.2018.10.034 PDF
Cristopher Cullis, Percy Chimwamurombe, Nigel Barker, Karl Kunert, Juan Vorster. (2018) Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study. Frontiers in Plant Science 9:11999. 10.3389/fpls.2018.01199 PDF
Magdeleen Cilliers, Stefan van Wyk, Phillipus van Heerden, Karl Kunert, Juan Vorster. (2018) Identification and changes of the drought-induced cysteine protease transcriptome in soybean (Glycine max) root nodules. Journal of Experimental and Environmental Botany 148:59-69. 10.1016/j.envexpbot.2017.12.005
Priyen Pillay, Karl Kunert, Eugene Makgopa, Chris Cullis, Juan Vorste. (2016) Agroinfiltration contributes to VP1 recombinant protein degradation. Bioengineered 7(6):459-477. 10.1080/21655979.2016.1208868 PDF
Foyer CH, Lam H-M, Nguyen HT, Siddique KHM, Varshney RK, Colmer TD, Cowling W, Bramley H, Mori TA, Hodgson JM, Cooper JW, Miller AJ, Kunert K, Vorster J, Cullis C, Ozga JA, Wahlqvist ML, Liang Y, Shou H, Shi K, Yu J, Fodor N, Kaiser BN, Wong F-L, Valliyodan B, Considine MJ. (2016) Neglecting legumes has compromised human health and sustainable food production. Nature Plants 2:16112. 10.1038/nplants.2016.112
Pillay P, Kunert KJ, van Wyk S, Makgopa ME, Cullis CA, Vorster BJ. (2016) Agroinfiltration contributes to VP1 recombinant protein degradation. Bioengineered 7(6):459-477. 10.1080/21655979.2016.1208868
Kunert K, Vorster BJ, Fenta BA, Kibido T, Dionisio G, Foyer CH. (2016) Drought stress responses in soybean roots and nodules. Frontiers in Plant Science 7(1015) 10.3389/fpls.2016.01015 PDF
Sapountzis P, de Verges J, Rousk K, Cilliers M, Vorster BJ, Poulsen M. (2016) Potential for Nitrogen Fixation in the Fungus-Growing Termite Symbiosis. Frontiers in Microbiology 7:1993. 10.3389/fmicb.2016.01993 PDF
Naidoo SIM, Laurie SM, Odeny DA, Vorster BJ, Mphela WM, Greyling MM, Crampton BG. (2016) Genetic analysis of yield and flesh colour in sweetpotato. African Crop Science Journal 24(1):61-73. 10.4314/acsj.v24i1.5 PDF
Sainsbury F, Jutras PV, Vorster J, Goulet MC , Michaud D. (2016) A Chimeric Affinity Tag for Efficient Expression and Chromatographic Purification of Heterologous Proteins from Plants. Frontiers in Plant Science 7:141. 10.3389/fpls.2016.00141
Van Wyk SG, Kunert KJ, Cullis CA, Pillay P, Makgopa ME, Schluter U , Vorster BJ. (2016) The future of cystatin engineering. Plant Science 246:119-127. 10.1016/j.plantsci.2016.02.016 PDF
van Wyk SG, Du Plessis M, Cullis CA, Kunert KJ, Vorster BJ. (2014) Cysteine protease and cystatin expression and activity during soybean nodule development and senescence. BMC Plant Biology 14(294) 10.1186/s12870-014-0294-3
Pillay P, Schlüter U, van Wyk S, Kunert KJ, Vorster BJ. (2014) Proteolysis of recombinant proteins in bioengineered plant cells. Bioengineered 5(1):15-20. 10.4161/bioe.25158
Vorster BJ, Schlüter U, du Plessis M, van Wyk S, Makgopa ME, Ncube I, Quain MD, Kunert K, Foyer CH. (2013) The Cysteine Protease – Cysteine Protease Inhibitor System Explored in Soybean Nodule Development. Agronomy 3(3):550-570. 10.3390/agronomy3030550
Vorster B, Schlüter U, du Plessis M, van Wyk S, Makgopa M, Ncube I, Quain M, Kunert K, Foyer C. (2013) The cysteine protease–cysteine protease inhibitor system explored in soybean nodule development. Agronomy 3(3):550-570. 10.3390/agronomy3030550
Mphangwe NIK, Vorster J, Steyn JM, Nyirenda HE, Taylor NJ, Apostolides Z. (2013) Screening of Tea (Camellia sinensis) for Trait-Associated Molecular Markers. Applied Biochemistry and Biotechnology 171:437-449. 10.1007/s12010-013-0370-4
Vorster BJ, Schlüter U, du Plessis M, van Wyk S, Makgopa M, Ncube I, Quain M, Kunert KJ, Foyer C. (2013) The Cysteine Protease–Cysteine Protease Inhibitor System Explored in Soybean Nodule Development. Agronomy 3(3):550-570.
Kunert KJ, Okole B, Vorster BJ, Brewin NJ, Cullis CA. (2012) A general model for training the next generation of biotechnology entrepreneurs based on recent experience of USA-UK-South Africa collaborations. Journal of Commercial Biotechnology 18:62-66. 10.5912/jcb.525
Pillay P, Kibido T, Du Plessis M, Van der Vyver C, Beyene G, Vorster BJ, Kunert KJ, Schlueter U. (2012) Use of Transgenic Oryzacystatin-I-Expressing Plants Enhances Recombinant Protein Production. Applied Biochemistry and Biotechnology 168(6):1608-1620. 10.1007/s12010-012-9882-6
Sainsbury F, Rheaume A-J, Goulet M-C, Vorster J, Michaud D. (2012) Discrimination of Differentially Inhibited Cysteine Proteases by Activity-Based Profiling Using Cystatin Variants with Tailored Specificities. Journal of Proteome Research 11:5983-5993. 10.1021/pr300699n
Afiukwa CA, Kunert KJ, Vorster J, Cullis CA, Ubi BE. (2011) Microsatellite association with seed protein content and flowering time in Nigerian cowpea cultivars. African Journal of Biotechnology 10:18057-18064. 10.5897/AJB10.2537
Van der Vyver C, Vorster BJ, Kunert KJ, Cullis CA. (2011) Analysis of radiation-induced genome alterations in Vigna unguiculata. Research and Reports in Biology 2:89-99. 10.2147/RRB.S22790
Benchabane M, Schluter U, Vorster J, Goulet M, Michaud D. (2010) Plant cystatins. Biochimie 92(11):1657-1666. 10.1016/j.biochi.2010.06.006
Khalf M, Goulet C, Vorster BJ, Brunelle F, Anguenot R, Fliss I, Michaud D. (2010) Tubers from potato lines expressing a tomato Kunitz protease inhibitor are substantially equivalent to parental and transigenic controls. Plant Biotechnology Journal 8(2):155-169. 10.1111/j.1467-7652.2009.00471.x
Kiggundu A, Muchwezi J, Van der Vyver C, Viljoen A, Vorster BJ, Schluter U, Kunert KJ, Michaud D. (2010) Deleterious effects of plant cystatins against the Banana weevil Cosmopolites sordidus. Archives of Insect Biochemistry and Physiology 73(2):87-105. 10.1002/arch.20342
Schluter U, Benchabane M, Munger A, Kiggundu A, Vorster J, Goulet M, Cloutier C, Michaud D. (2010) Recombinant protease inhibitors for herbivore pest control: a multitrophic perspective. Journal of Experimental Botany 61(15):4169-4183. 10.1093/jxb/erq166
Cullis CA, Vorster BJ, van der Vyver C, Kunert KJ. (2009) Transfer of genetic material between the chloroplast and nucleus: how is it related to stress in plants?. Annals of Botany 103(4):625-633. 10.1093/aob/mcn173
Vorster BJ, Kunert KJ, Cullis CA. (2002) Use of representational difference analysis for the characterization of sequence differences between date palm varieties. Plant Cell Reports 21(3):271-275. 10.1007/s00299-002-0501-9