Several sub-projects in this field aim to increase our understanding of the inhibition and regulation of cysteine protease activity by plant cystatins. This includes the role of cysteine proteases and cystatins during nodule development and senescence in soybean as well as the possibility of using cystatins to increase abiotic stress resistance in nodules. A further project relates to the inhibition of insect digestive proteases by plant cystatins and their potential for use in developing insect resistant crops.

We study the function and importance of specific amino acids in the cystatin proteins using techniques such as homology modelling and protein-protein docking to study and predict specific interactions in silico. We also change specific amino acids in the proteins through site-directed mutagenesis in order to study their effect on the inhibition potential of the modified cystatins in vitro. Selected cystatins have also been recombinantly expressed in various plants to evaluate their role in vivo particularly in repressing senescence and protein degradation.

New Publications

Cullis C, Chimwamurombe P, Kunert K, Vorster J. (2022) Perspective on the present state and future usefulness of marama bean (Tylosema esculentum). Food and Energy Security :1-11. 10.1002/fes3.422 PDF
Reinhardt CF, Vorster BJ, Kupper A, Peter F, Simelane A, Friss S, Magson J, Aradhya C. (2022) A nonnative Palmer amaranth (Amaranthus palmeri) population in the Republic of South Africa is resistant to herbicides with different sites of action. Weed Sience 10.1017/wsc.2022.9 PDF
Tremblay J, Goulet M-C, Vorster J, Goulet C, Michaud M. (2021) Harnessing the functional diversity of plant cystatins to design inhibitor variants highly active against herbivorous arthropod digestive proteases. The FEBS Journal 10.1111/febs.16288 PDF
Sukhorukov AP, Kushunina M, Reinhardt CF, Bezuidenhout H, Vorster BJ. (2021) First records of Amaranthus palmeri, a new emerging weed in southern Africa with further notes on other poorly known alien amaranths in the continent . BioInvasion Records 10(1):1-9. 10.3391/bir.2021.10.1.01 PDF
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