The Molecular Plant Physiology group was established in 1998 when Professor Karl Kunert joined FABI. Since then the group has grown and is currently headed by Dr Juan Vorster. We collaborate with various groups from around the world, each brining unique specialities, to understand plant development and the response of plant towards stress. Using a multi-disciplinary approach we hope to obtain a holistic view of the changes in the plant under stress. On a genomic level we have studies stress induced mutations and rearrangements of the genome, we are also using transcriptomics to study and identify genes and pathways that are important during the stress response. On a protein level we are especially interested in the role cysteine proteases as well as cysteine protease inhibitors play during development and senescence. Here we make use of in silico protein modelling to study protein-protein interactions as well as to predict the effect of mutations on inhibitor binding. Through protein engineering and enzyme kinetics we then evaluate the effect of these changes on inhibitor strength and specificity. We also measure protease activity and changes in the REDOX state in different tissues and under different stress conditions. To complement the molecular data we also follow and characterize various physiological and phenotypic changes in the plants we study. The ultimate aim is to identify usable molecular, biochemical or phenotypic markers that can be used to develop plants better adapted to stress in a changing environment.

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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
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
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.
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