Project description:Cowpea (Vigna unguiculata) is an important protein source in Sub-Saharan Africa. Optimizing resilience and productivity through genetic engineering in cowpea has been slow due in part to a lack of defined species-specific regulatory elements and difficulty testing gene function within the native system. In many plant species, Agrobacterium-mediated transient gene expression is widely used to validate constructs before investing in transgenic lines, but its implementation in legumes has been challenging. In this study, we optimized an in planta agroinfiltration assay in trifoliate cowpea leaves using a betalain reporter. To demonstrate the “intact plant” aspect of this system, we used this assay to characterize drought-inducible promoters by challenging cowpea plants with drought stress. Subsequently, to identify and broaden the pool of native promoters known in cowpea, we developed a user-friendly web application, CowPEAsy, allowing users to interrogate gene expression from our canopy-level, developmental-series RNA-Seq dataset. Finally, using CowPEAsy, we identified six promoters that showed constitutive expression across all conditions and verified these promoters with our transient system. This work provides an in vivo platform for preliminary validation of regulatory elements in cowpea and other legumes and enhances current genetic resources by identifying a suite of physiologically relevant promoters of varying strengths.
Project description:In this study we have looked at the transcriptome profile of both incompatible and compatible cowpea-RKN interaction for two different time points using the Affymetrix soybean GeneChip. This is the first study of this kind in cowpea-RKN interaction. This study provides a broad insight into the Rk-mediated resistance in cowpea and creates an excellent dataset of potential candidate genes involved in both nematode resistance and parasitism, which can be further tested for their role in this biological process using functional genomics approaches. our results have shown that the root-knot nematode resistant pathway is still partially suppressed at 9 days post inoculation in resistant cowpea root. There is indication that subtle variation of ROS concentration, induction of toxins and other defense related genes play a role in this unique resistance mechanism. Further functional analysis of these differentially expressed genes will help us to understand this intriguing plant-nematode interaction in a more precise manner.
