Influence of an m-type thioredoxin in maize on potyviral infection

Abstract

Expression of many host genes can be altered during virus infection. In a previous study of sugarcane mosaic virus (SCMV) infection in maize (Zea mays), we observed that expression of ZmTrm2, a gene encoding thioredoxin m, was up-regulated at about 10 days post-inoculation (dpi). In this present study we determined that ZmTrm2 silencing in maize by virus-induced gene silencing significantly enhanced systemic SCMV infection. In contrast transient over-expression of ZmTrm2 in maize protoplasts inhibited accumulation of SCMV viral RNA. Furthermore, we found that in inoculated Nicotiana tabacum leaves transient expression of ZmTrm2 inhibited accumulation of the RNA of tobacco vein-banding mosaic virus (TVBMV), a potyvirus infecting dicotyledonous plants. Interestingly in ZmTrm2 transiently expressed N. tabacum leaves, we detected by semi-quantitative RT-PCR a reduced level of the mRNA of class I beta-1, 3-glucanase (GluI), a protein known to have a role in cell wall callose deposition and viral movement. Our data indicate that the maize ZmTrm2 plays an inhibitory role during infection of plants by SCMV and TVBMV.