Fungal strains can be allies against Striga


The overall objectives of Promise II are to identify and deliver affordable substrates, fungal inoculants, bacterial inoculants and microbial inoculants that induce multilayered resistance in the host crops. All of this work, is organized in four different interlinked workpackages described belo

Victoria Miles, NIOO-KNAW
Workpackages within Promise


Substrates and Strigacidal Volatiles

In the first stage of PROMISE II, we will test the effects of different organic substrates that trigger Strigacidal volatile production by specific soil microorganisms, and how this affects Striga seed germination and viability. These substrates will range from waste streams originating from plants and animals to brown macroalgae or insects. We will assess the impact of these substrates for different Striga species and Striga ecotypes collected from sorghum, rice and millet field sites in Ethiopia, Senegal and Tanzania. 

Image: Jos Raaijmakers, NIOO-KNAW

Tested Soils


Fungal Inoculants

During this project we will also develop and deliver fungal inoculants that reduce the Striga seedbank. Initially, we will evaluate selected fungal strains to ensure they do not pose any pathogenic risks to different genotypes of sorghum, millet, and rice. Following a series of tests, we will identify strains that effectively combat the Striga seedbank and are suitable for fermentation. Finally, we will test the selected fungal strains in small-scale trials in our study region. 

Image: Jose G. Macia-Vicente, NIOO-KNAW



Bacterial Inoculants

During the completion of this project we will develop microbial inoculants that reduce the Striga seedbank by triggering suicidal germination or causing seed decay. To start with, we will evaluate the selected microbial strains to ensure their safety and then we will identify those those that effectively combat the Striga seedbank and at the same time are suitable for large-scale fermentation. Finally, we will test the selected strains in small-scale field trials in Ethiopia, Senegal and Tanzania. Furthermore, we will formulate microbial inoculants capable of degrading germination stimulants and haustorium-inducing factors. After rigorous testing, we will pinpoint the strains that effectively prevent Striga infections and conduct small-scale field trials with sorghum, rice and millet. 

Image: Cross-sections of sorghum roots (brightly stained concentric circles in pink that are infected by Striga hermonthica. Tamera Taylor, UC Davis 

Cross-sections of sorghum roots (brightly stained concentric circles in pink that are infected by witchweed (Striga hermonthica). The researchers showed that soil microbes help sorghum resist witchweed infections by inducing changes in sorghum root structure. (Tamera Taylor / UC Davis)


Root Chemistry and Structural Barriers 

We will also develop microbial inoculants that induce physical barriers in the roots of the crop plants that limit Striga infections. The multifaceted approach developed in PROMISE II is focused on adversely affecting different stages of the Striga life-cycle and to be integrated with existing control strategies, including Striga resistant crop germplasm and novel chemical technologies that target the Striga seedbank.

Image: Jos Raaijmakers, NIOO-KNAW

Sorghum field infected with sorghum