Identification and analysis of viral sequences in peanut (Arachis hypogaea L.) expressed sequence tags

Crop plants grown in the field have been naturally infected with different viruses resulting in economic yield loss. In peanut, Tomato spotted wilt Tospovirus (TSWV), causes plant disease in major production area such as Southeastern United States. The objectives of this study were to investigate peanut sequences of expressed sequence tags (ESTs) for viral nucleotide sequences, to identify possible new viruses, and to develop control strategies of potential viral diseases. We have sequenced a total of 44,064 clones from 10 peanut cDNA libraries, derived from developing seeds at three reproduction stages (R5, R6 and R7) and from leaf tissues of a resistant and a susceptible cultivated peanuts, "Tifrunner" (a runner type, resistant to TSWV) and "GT-C20" (a Spanish type, susceptible to TSWV). We investigated the extent of viral sequences in these peanut ESTs and detected the sequences of Peanut mottle virus (PMV), Peanut stripe virus (PStV), Tomato spotted wilt virus (TSWV), and a potential Tobamovirus. A total of 942 sequences were identified matching viral sequences in the GenBank to PMV (606), PStV (330), and TSWV (6). We identified one peanut sequence with homologue to a pea (Pisum sativum) plant-specific Potyvirus VPg-interacting protein (PVIP) and two tobamovirus related plant proteins, a tobamovirus multiplication protein 3 (TOM3) and a Tobacco mosaic virus (TMV) helicase domain-binding protein, with homologues to Arabidopsis thaliana. These host proteins are essential for viral multiplication and movement from cell to cell in host plants. The presence of tobamovirus plant-responsive proteins suggests that peanut may be a host for tobamovirus. Further study of peanut putative PVIP, TOM3 and TMV helicase domain-binding proteins will enable the development of new control strategies.