ESTs from a wild Arachis species for gene discovery and marker development

ESTs were produced from four cDNA libraries of RNAs extracted from leaves and roots of A. stenosperma. Randomly selected cDNA clones were sequenced to generate 8,785 ESTs, of which 6,264 (71.3%) had high quality, with 3,500 clusters: 963 contigs and 2537 singlets. Only 55.9% matched homologous sequences of known genes. ESTs were classified into 23 different categories according to putative protein functions. Numerous sequences related to disease resistance, drought tolerance and human health were identified. Two hundred and six microsatellites were found and markers have been developed for 188 of these. The microsatellite profile was analyzed and compared to other transcribed and genomic sequence data.This is, to date, the first report on the analysis of transcriptome of a wild relative of peanut. The ESTs produced in this study are a valuable resource for gene discovery, the characterization of new wild alleles, and for marker development. The ESTs were released in the [GenBank:EH041934 to EH048197].Peanut or groundnut (Arachis hypogaea L.) is the fourth most important oil seed in the world, cultivated mainly in tropical, subtropical and warm temperate climates [1]. It is an important crop for both human and animal food. Its yields are reduced around the world by diseases including fungal leaf-spots caused by Cercospora arachidicola [Hori] and Phaseoisariopsis personata [Berk. & MA Curtis], the rust Puccinia arachidis [Speg.], groundnut rosette disease, and root-knot nematodes (Meloidogyne ssp.), the later causing losses of up to 12% in United States and India [2]. High salinity and drought are also important reducers of yield in many parts of the world.Wild relatives are an important source of genes for resistances to biotic and abiotic stresses that affect crop species. The genus Arachis arose in South America and its approximately 80 species have adapted to a wide range of environments. The cultigen A. hypogaea probably arose from a single or few events of hybri