ARS | Publication request: Identification and characterization of expressed resistance gene analogs (RGSs) from peanut (Arachis hypogaea L.) expressed sequence tags (ESTs)

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: January 2, 2012
Publication Date: February 5, 2012
Citation: Liu, Z., Culbreath, A., Guo, B. 2012. Identification and characterization of expressed resistance gene analogs (RGSs) from peanut (Arachis hypogaea L.) expressed sequence tags (ESTs). Phytopathology. 102:52.7.

Technical Abstract: Cultivated peanut (Arachis hypogaea L.) is an important food legume grown worldwide for providing edible oil and protein. However, due to scarcity of genetic diversity, peanut is very vulnerable to a variety of pathogens, such as rust (Puccinia arachidis Speg.), early leaf spot (Cercospora arachidicola S. Hori), late leaf spot (Cercosporidium personatum Berk. & M.A.Curtis), and Tomato spotted wilt virus (TSWV). Large number of peanut ESTs (225,264 ESTs by 11-11-2011) has been developed in recent years by peanut community, providing resources for gene identification and marker development. Based on the homology to typical pathogen resistance genes and the conservative domains/features, we identified 401 resistance gene analogs (RGAs), using a stringent BLAST search. By using 54 known R-gene protein sequences, we screened peanut EST database and identified 995 ESTs targeting different classes of known R genes. Among the 995 ESTs, 559 (56%) are from cultivated peanut (ten genotypes) and 436 (44%) are from three wild peanut genotypes. After assembly, 401 unigenes including 152 contigs and 249 singletons were identified and considered as peanut expressed RGAs. These expressed RGAs are comprised of 75, 196, 89, 27, and 14 RGAs representing for NBS-LRR, protein kinase (PK), LRR-PK/TM, Toxin reductase, and other domain encoding R genes, respectively. The expressed RGAs identified in this study provide a large sequence dataset for RGA-tagged potential markers that could be developed further for use in mapping and ultimately cloning disease resistance genes in peanuts.