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

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
Malefo M, Mathibela O, Makgopa E, Crampton BG. (2020) Investigating the role of Bowman-Birk serine protease inhibitor in Arabidopsis plants under drought stress. Plant Physiology and Biochemistry 149:286-293. 10.1016/J.PLAPHY.2020.02.007
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