Mr Tshepo Joseph Mmushi

PhD student


Biochemistry, Genetics and Microbiology
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Primary Supervisor
Thabiso Motaung

My interest in studying the interactions between microbes and plants started when I undertook my Honours degree. This was followed by my Masters study in the later years, which focused on antimicrobial activities of a wide variety of plants against different types of microorganisms. The main aim of the study was to isolate and characterise bioactive molecules from plants. This has resulted in a curiousity to seek an understanding of these interactions at a molecular level.

This background seamlessly aligns with my current interest in naturally released nanoparticles known as extracellular vesicles (EVs), specifically plant-derived extracellular vesicles (PDEVs). PDEVs encapsulate a rich repertoire of bioactive molecules, including coding (mRNAs) and noncoding RNAs (microRNAs, siRNAs), proteins, lipids, and secondary metabolites.

The accessibility of protocols for vesicle isolation and purification, coupled with the biocompatibility of EVs with diverse recipients, including fungal cells, and the stability exhibited by EVs, positions their exogenous application well within our grasp. My Ph.D. research, conducted under the supervision of Dr. Thabiso Motaung, will therefore focus on exogenous PDEVs from planted Pinus elliottii (slash pine) across South African provinces.

This work will look into co-cultivating PDEVs with Fusarium circinatum, a worrisome pathogen of pines, and other unrelated filamentous species with key economic importance. The goal is to assess the broad applicability of PDEVs in various plant-fungal interaction scenarios. In addition, I will explore whether PDEVs showcase holistic curative properties for overall plant health, given that their pre-emptive properties have already been demonstrated by our team. My project is part of the ongoing with the overarching objective of unravelling the mechanisms governing EVs in pine-pathogen interactions, ascertaining the value of isolated EVs as a source of antifungal compounds, and identify potential novel antifungal targets for managing pine pitch canker effectively in the future.