ENGINEERING COWPEA [Vigna unguiculata (L.) Walp.] FOR PEST RESISTANCE
Bosibori B. Bett
Cowpea is a semi-arid crop widely cultivated in Africa, Latin America, Southeast Asia and Southwestern regions of North America with a world annual production of approximately 3.9 million metric tons. In the developing world, cowpea is an important source of dietary protein, vitamins and minerals, ranking third after seed legumes in some parts. Additionally, the crop is used for food, fodder and as a source of income.
Problem statement and Justification
Cowpea production is constrained by biotic and abiotic stresses including insects, bacteria, fungi and viruses. The crop hosts a broad range of pests including pod borers, leaf hoppers, aphids, flower bud thrips, with the pod borer causing a serious loss of grain yield. Cowpea is also susceptible to many viral diseases including Cowpea aphid borne mosaic virus, Cowpea severe mosaic virus, Blackeye cowpea mosaic virus and Cowpea yellow mosaic virus. Losses amount between 10 and 100 % due to virus infections. Genetic engineering approaches can offer alternative means to alleviate cowpea production constraints for the small holder farmers in sub-Saharan Africa. Although there have been successful efforts to transform and regenerate cowpea; however, there is need to apply the same techniques to African preferred varieties. The development of African cowpea varieties protected against pests and diseases offers a means to obtain resistant material for the smallholder farmer in Africa.
To develop resistant cowpea against viral and insect pests via genetic engineering by optimizing transformation and regeneration protocols. The specific objectives of the proposed study include:
To optimize the regeneration of a farmer-preferred cowpea variety.
To transform the explants with genes conferring insect resistance via Agrobacterium tumefaciens.
To transform the explants with genes conferring virus disease resistance via Agrobacterium tumefaciens.
To carryout molecular characterization of the cowpea transgenic plants.
To screen the transgenic lines for pest and disease resistance in the greenhouse.
The development of African cowpea varieties protected against pests and diseases offers a means to obtain resistant material for the smallholder farmer in Africa. The transfer of genes with resistance traits to African cowpea varieties remains an attractive option as this will go some way to improve the yields of cowpea production and quality. From this study, a reproducible regeneration and transformation system for cowpea will be optimised. This study will go some way in producing cowpea cultivars with desirable traits and contribute to the food security status of the continent. Additionally, this will improve the livelihoods of the rural communities at household level.