Warsame Group: Decoding transcriptional dynamics underlying drought stress responses in cowpea
Supervisor
Dr. Ahmed Warsame
Brief Summary
Drought stress elicits intricate transcriptional reprogramming in plants, which plays a pivotal role in their adaptive responses. Unravelling the transcriptomic landscape and gene networks under drought stress can facilitate the identification of key drought-responsive genes and pathways that underlie drought tolerance and can be targeted to enhance drought tolerance.
Importance of Research
Cowpea (Vigna unguiculata), despite its natural adaptation to arid environments in sub-Saharan Africa, its production is constrained by frequent and severe drought conditions exacerbated by climate change. This study aims to elucidate the molecular mechanisms underpinning drought tolerance in cowpea by identifying candidate genes and regulatory networks involved in drought responses. The findings will advance our understanding of drought adaptation in cowpea, and will have potential application in breeding or engineering drought-tolerant cowpea and related legume species.
Project summary
Drought tolerance in crops is mediated by a suite of physiological responses, including enhanced cellular osmotic adjustment, improved oxidative stress management, increased water-use efficiency through regulated transpiration, and activation of stress signalling pathways. Each of these responses is orchestrated by dynamic changes in gene expression and regulatory hubs. While cowpea accessions exhibiting superior drought tolerance have been identified through seedling-stage screening and field-based yield assessments, the molecular basis of their resilience remains poorly characterized.
This project will employ RNA sequencing to delineate the transcriptomic signatures of drought stress responses in cowpea accessions with contrasting drought tolerance phenotypes. The study will profile gene expression under severe and moderate drought conditions across multiple growth stages. The resulting data will reveal critical candidate genes and pathways implicated in drought responses. Additionally, the project will investigate the expression patterns of genes associated with the accumulation of antinutritional compounds (e.g., phytic acid, raffinose, condensed tannins) under stress, offering potential targets for reducing these compounds without compromising plant resilience.
What will a successful applicant do?
This project will involve RNA sequencing to analyze gene expression changes in drought-tolerant and drought-susceptible cowpea accessions subjected to varying drought intensities at distinct developmental stages. Bioinformatic tools will be used to identify key regulatory modules and hub genes associated with drought tolerance. Next, model systems such as Medicago truncatula and Arabidopsis thaliana mutant lines will be used for functional validation of candidate genes or transcription factors. Finally, comparative genomic analyses will be conducted using publicly available legume genomic data to explore the evolutionary basis of cowpea’s adaptation to arid environments.
References
1. Shen, J., et al., Physiology and transcriptomics highlight the underlying mechanism of sunflower responses to drought stress and rehydration. iScience, 2023. 26(11): p. 108112. doi: 10.1016/j.isci.2023.108112
2. Fatokun, C.A., O. Boukar, and S. Muranaka, Evaluation of cowpea (Vigna unguiculata (L.) Walp.) germplasm lines for tolerance to drought. Plant Genetic Resources, 2012. 10(3): p. 171-176. doi: 10.1017/S1479262112000214
3. Boukar, O., et al., Cowpea (Vigna unguiculata): Genetics, genomics and breeding. Plant Breeding, 2019. 138(4): p. 415-424. doi: 10.1111/pbr.12589