Analysis and RT-PCR Identification of Viral Sequences in Peanut (Arachis hypogaea L.) Expressed Sequence Tags from Different Peanut Tissues

In the Southeastern US, peanut plants are often naturally infected with different viruses resulting in economic losses. Limited information is available concerning the identification and characterization of various viruses in peanut. A collaborative effort has resulted in the production of 44,064 expressed sequence tags (ESTs) from developing seeds at three reproductive stages (R5, R6 and R7) of two peanut genotypes, Tifrunner and GT-C20 and from field collected leaf tissues using the same two genotypes. EST sequences were analyzed, assembled and putative functions were determined based on the comparison of these unique peanut sequences with the National Center of Biotechnology Information (NCBI) non-redundant (nr) database using BLASTX program. Sequences matched viral or viral associated proteins were selected for further study. We analyzed the extent of viral sequences in these peanut ESTs and detected the sequences of Peanut mottle virus (PMV), Peanut stripe virus (PStV) and Tomato spotted wilt virus (TSWV). A total of 942 sequences were identified that matched viral sequences in GenBank to PMV (606), PStV (330) and TSWV (6). We also identified peanut plant sequences with homology to pea (Pisum sativum) plant-specific Potyvirus VPg-interacting protein (PVIP), Arabidopsis thaliana tobamovirus multiplication protein 3 (TOM3) and a tobacco TMV helicase domain-binding protein. These host proteins are essential for viral multiplication and movement from cell to cell in host plants. Further study, we examined and identified the presence of these viral and plant sequences in peanut leaves, seeds and roots using RT-PCR. The potential use of these putative peanut virus host responsive proteins may lead to the development of potentially new strategies to control these virus diseases by silencing or disrupting these genes to prevent virus infection and multiplication in host plants.