Breaking the witches' spell: towards steering the soil microbiome for volatile-mediated control of the root parasitic weed Striga
Striga hermonthica, commonly known as witchweed, infests major cereal crops in Sub-Saharan Africa causing severe yield losses and threatening the livelihood of millions of resource poor farmers.
- Masteling Pereira, R.
- 12 April 2023
- Thesis in Leiden Repository
Despite the use of herbicides, Striga-resistant crop varieties and agronomic practices to mitigate the impact of Striga, these are not effective on their own and require high monetary investments by smallholder farmers. My PhD research focuses on the potential of soil microbes to disrupt the early stages of the parasite’s life cycle through the production of volatile organic compounds. More specifically, we developed a computer vision tool that enabled the large-scale screening of a large bacterial collection for its functional potential to suppress Striga seed germination by naturally produced volatile compounds. This was complemented with the identification of several Striga-suppressive volatile compounds and studies into their genomic regulation. We developed a new approach of ‘precursor-directed activation’ of Striga-suppressive soil microbes by amending field soils with amino acid precursors to suppressive volatile compounds. This strategy will enable better deployment of volatile-mediated Striga suppression under field settings, by steering its production in situ and by aiding in the development of future control methods with higher efficacies and lower application costs.