1 Cowpea: a legume crop for a challenging environment Running title: Cowpea for a challenging environment Márcia Carvalho 1 , Teresa Lino-Neto 2* , Eduardo Rosa 1 and Valdemar Carnide 1,3 1 Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), 5001-801 Vila Real, Portugal; 2 BioSystems & Integrative Sciences Institute (BioISI), Plant Functional Biology Centre, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal 3 Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, UTAD, Quinta dos Prados, 5001-801 Vila Real, Portugal *Corresponding author: Teresa Lino-Neto, e-mail – tlneto@bio.uminho.pt; phone: +351 253601544; fax: +351 253604319; address: Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal Abstract Cowpea is a grain legume native from Africa and is a primary source of protein for millions of people in sub-Saharan Africa and other parts of the developing world. The main important characteristics of this crop include the good protein quality with a high nutritional value, the nitrogen-fixing ability, and be more drought- and heat-tolerant than most of its legume relatives. In a research perspective, the studies with cowpea are relatively scarce, despite its relevance to agriculture in the developing world and its resilience to stress. This review provides an overview on different aspects of cowpea, with special emphasis on the molecular