Lilitha Mwasi Njobe is a PhD candidate in the School of Agriculture, Food and Wine at the University of Adelaide. Based in the Herbicide and Antimicrobial Innovation Laboratory, her research investigates the role of extracellular vesicles in the transfer of herbicide resistance in Lolium rigidum, one of the world’s most problematic agricultural weeds. Her broader research interests include sustainable agriculture and science communication.

Lilitha obtained her Master of Science Wine Biotechnology in 2024 with a SAGWRI research project on the influence of antifungal interkingdom microbial consortia on wine fermentation kinetics and chemical composition, funded by South Africa Wine.

Lilitha Njobe
Lilitha Mwasi Njobe

Please give a brief overview of your SAGWRI research project?

Biological control agents (BCAs) are gaining increasing interest as sustainable alternatives to synthetic fungicides for managing grapevine pathogens, particularly because they can be applied closer to harvest and reduce the risk of harmful agrochemical residues. While the effects of synthetic fungicide residues on wine quality have been well documented due to their transfer from grapes to must during winemaking, the impact of BCAs on wine production remains largely unexplored, despite their increasing use in vineyards.

This study therefore investigated the oenological impact of two microbial consortia with biocontrol potential against Botrytis cinerea. The research focused on how these consortia influence wine yeasts and fermentation kinetics. Population dynamics and fermentation performance were assessed in a synthetic grape juice medium, both in the absence and presence of commercial strains of Saccharomyces cerevisiae, Torulaspora delbrueckii, and Lachancea thermotolerans. In addition, the microbial consortia were applied to Vitis vinifera L. cv. Merlot grapes, and their persistence and behaviour were evaluated during both spontaneous and inoculated fermentations.

The study specifically examined the effects of these antifungal consortia on bacterial and fungal community dynamics as well as on alcoholic and malolactic fermentation processes. Analyses included measurements of primary metabolites, volatile aroma compounds, and biogenic amines produced during alcoholic fermentation, providing a comprehensive understanding of how these antifungal microbial consortia influence the overall winemaking process.

How did the project align with industry priorities?

The project aligned closely with industry priorities by addressing the global shift towards sustainable agricultural practices that aim to reduce chemical inputs while maintaining high-yielding, high-quality crops. In viticulture, managing plant diseases remains a critical challenge because they can significantly affect both yield and grape quality. At the same time, the industry faces increasing pressure to reduce reliance on synthetic fungicides due to their environmental impact, risks to human health, the development of fungicide-resistant pathogens, and concerns about chemical residues in grapes and wine.

In response to these challenges, there is a strong industry focus on integrated pest management strategies, including the use of biological control agents. BCAs are increasingly recognised as environmentally friendly alternatives for disease management in vineyards and are already applied at key stages of grapevine development. However, despite their growing adoption, there is limited understanding of how these agents influence downstream winemaking processes and final wine quality.

This project addressed this gap by evaluating the oenological impact of microbial consortia with biocontrol potential, providing insights highly relevant to industry concerns around fermentation performance, microbial community dynamics, and wine quality. Furthermore, the use of microbial consortia reflects emerging industry interest in improving the consistency and efficacy of BCAs under variable vineyard conditions.

How could your research be applied in the industry?

This research provides practical insights for the wine industry, supporting the adoption of more sustainable disease management strategies without compromising wine quality. Understanding the persistence and behaviour of these biocontrol agents during fermentation, especially when applied close to harvest, enables producers to integrate them effectively into vineyard practices and minimise risks such as sluggish fermentations or unintended changes in aroma profiles.

The study highlights the oenological characteristics of antifungal microbial consortia, including their impact on fermentation kinetics and organoleptic properties, and provides an important early investigation into the role of microbial consortia as emerging practices shape the future of viticulture. By demonstrating that BCAs can be applied in vineyards without compromising wine quality, the study supports their practical implementation and bridges the gap between sustainable viticulture and consistent, high-quality wine production.

What is innovative about your research?

This research is innovative in that it moves beyond the traditional evaluation of the effectiveness of biological control agents in the vineyard to examine their downstream effects on winemaking processes and wine quality. While most studies focus primarily on the efficacy of BCAs in controlling plant pathogens, this work addresses a critical and underexplored question of how these agents influence fermentation dynamics and oenological outcomes.

A key aspect of the study is the focus on microbial consortia rather than single strain BCAs. By investigating combinations of microorganisms with biocontrol potential, the research reflects emerging strategies aimed at improving efficacy and stability of BCAs under variable environmental conditions, while also capturing the complexity of microbial interactions during fermentation.

What are you currently working on?

My current research at the University of Adelaide, titled “Extracellular Vesicles as Potential Mediators of Herbicide Resistance,” investigates whether extracellular vesicles (EVs) facilitate the transfer of herbicide resistance in Lolium rigidum, a major and highly resistant agricultural weed. The project explores a previously uncharacterised mechanism of resistance, assessing whether EVs can transport resistance-associated molecules between cells and whole plants, thereby enabling the spread of resistance traits. It also examines whether inhibiting EV secretion can restore herbicide sensitivity.

In addition, the project involves identifying and characterising the molecular targets of EV inhibitors to guide the development of more effective, plant-specific inhibitors. Ultimately, this research aims to provide insights into a potential novel herbicide resistance mechanism and evaluate whether targeting EVs could extend the effectiveness of existing herbicides, supporting more sustainable weed management strategies.

What prompted you to pursue this topic?

My interest in this research stems from the growing challenge of chemical resistance in agriculture. While my research focuses on weeds that are increasingly evolving resistance to herbicides, viticulture faces a similar issue, with plant pathogens developing resistance to fungicides. Considerable effort has been dedicated to understanding how resistance emerges and spreads in order to preserve the effectiveness of current and future crop protection tools.

One mechanism that has attracted significant attention in mammalian systems, particularly in cancer research, is the role of EVs in transferring drug resistance between resistant and sensitive cells. This inspired me to investigate whether a similar process could occur in plants, exploring whether EVs contribute to the spread of herbicide resistance in Lolium rigidum.

The work also has broader relevance to the wine industry, as EVs have been identified in important plant pathogens such as Botrytis cinerea. If EVs play a role in spreading resistance traits in plants or, potentially, in plant pathogens, understanding and inhibiting this process could help preserve the effectiveness of current herbicides and fungicides, supporting more sustainable vineyard management and long-term productivity.

What other areas do you think merit more research for the wine industry in South Africa?

I think considerable research is being conducted across many important areas of the wine industry, from climate change adaptation and vineyard microbiome research to the development of biological control strategies. However, one area that I believe deserves greater attention is research that bridges the gap between scientific innovation and industry adoption. While developing innovative solutions is important, understanding how growers can implement new technologies and management strategies in practice is equally critical.

There is often a disconnect between research findings and what is ultimately adopted in vineyards. Greater emphasis on knowledge transfer and the practical application of research outcomes could help ensure that scientific advances translate into meaningful improvements in the wine sector, supporting its long-term sustainability and profitability.

What advice would you give to young scientists?

Young scientists who want to make a meaningful impact in the wine industry should build a strong interdisciplinary foundation. The sector is inherently complex, and the ability to integrate knowledge across disciplines, something I gained from studying at SAGWRI, is essential for addressing real-world challenges. It is equally important to stay aligned with industry priorities, particularly the growing focus on sustainability and environmentally responsible practices. A clear understanding of current challenges helps ensure that research remains both relevant and impactful.

Effective science communication is also critical. Translating complex findings into practical, accessible recommendations drives adoption within the industry. Whether through reports, presentations, or informal discussions, strong science communication skills help bridge the gap between research and application.

Finally, adaptability and openness to innovation are key. The wine industry is evolving rapidly, with increasing interest in new technologies, alternative production methods, and sustainable solutions. Curiosity, collaboration, and a willingness to explore new approaches will position young scientists to contribute meaningfully to the industry’s future.