Title : Metabolite and transcriptome profiling reveals drought adaptive strategies in the orphan African cereal, tef (eragrostis tef)
Abstract:
Background: Tef (Eragrostis tef), is a nutritious, gluten-free cereal rich in protein, fibre, vitamins, and minerals. It represents a good alternative cereal for individuals with gluten intolerance, such as those with celiac disease. Despite originating in Ethiopia, tef yields are limited due to drought stress. As an emerging crop, little is understood of its responses to challenging environments, therefore, characterising the key gene-metabolite changes under drought will be important in the derivation of new, elite climate-smart tef varieties.
Objectives: This study aimed to screen and characterize the response of diverse tef genotypes to drought stress.
Methods: For the current study four tef genotypes (Alba, Ent, Tsedey, and Manyi) were used. Three-week-old, tef seedlings were subjected to 15% (severe drought) water levels for 4 to 8 days, and their responses were compared to well-watered controls (65% water levels). The seedlings were harvested at the end of time points for metabolite and transcriptome profiling. The aerials parts of the seedlings were analysed for metabolite changes using direct infusion-high resolution mass spectrometry (DI-HRMS) and expression profile of genes were done using Illumina based RNA-sequencing. Datasets and outputs from metabolomics and transcriptomics were analysed using R-based statistical packages.
Results: Metabolomic analyses revealed that drought caused a significant increase in the osmolytes (sugars) and stress metabolites (proline). More species-specific responses centred on major shifts in flavonoid metabolism, including kaempferol 3-O-rhamnoside-7-O-glucoside, afzelechin, and eriodyctiol; which may have an antioxidant role. Such changes could be linked to the results of transcriptomic profiling which indicated significant increases in genes of the phenylpropanoids biosynthesis pathway and substantial changes in sugar metabolism. Both omics assessments suggested increases in the jasmonate (JA) phytohormone pathway which has been shown to be important to drought responses in other cereal species.
Conclusions: The observed shifts in JA and the flavonoid metabolism pathway could highlight an adaptive mechanism that could be important in tef's responses to drought stress. Boosting these pathways would be important in targeted breeding programs aiming to develop new varieties of drought-tolerant tef. This research contributes to our understanding of the molecular responses of tef to environmental stress, shedding light on the development of resilient crops to ensure food security in the face of changing climate conditions.
Keywords: Tef, Drought, Metabolomic, Transcriptomic, gluten-free
Audience Take Away:
The study will provide valuable insights for researchers;
- To identify pathways associated with drought stress response in tef or other cereals.
- These pathways could be targeted in breeding programs aiming to develop resilient cereals in water-scarce environments.
- Showcase tef's nutritional richness as a superior gluten-free cereal.
- Promote tef as a sustainable and nutritious choice, addressing dietary needs for gluten-intolerant individuals while enhancing overall nutritional intake.
