Development of resistant transgenic soybeans with inverted repeat-coat protein genes of soybean dwarf virus

Abstract

In an attempt to generate soybean plants resistant to soybean dwarf virus (SbDV), we transformed a construct containing inverted repeat-SbDV coat protein (CP) genes spaced by beta-glucuronidase (GUS) sequences into soybean somatic embryos via microprojectile bombardment. Three T(0) plants with an introduced CP gene were obtained, and one generated T(1) seeds. The presence of the transgene in T(1) plants was confirmed by PCR and Southern blot hybridization analysis, but expression of CP was not detected by northern blot hybridization analysis. Two months after inoculation of SbDV by aphid, T(2) plants contained little SbDV-specific RNA and remained symptomless. These plants contained SbDV-CP-specific siRNA. These results suggest that the T(2) plants achieved resistance to SbDV by an RNA-silencing-mediated process.

Robust RNAi-Based Resistance to Mixed Infection of Three Viruses in Soybean Plants Expressing Separate Short Hairpins from a Single Transgene

“…However, it is unclear whether RNAi played a major role in this case as the authors did not determine whether resistance correlated with vsRNA-mediated degradation of viral or transgene RNA (14). On the other hand, the SbDV resistance observed by Tougou and colleagues (17) was due primarily to RNAi activity as the SbDV-specific transgene contained an inverted repeat (IR) of SbDV CP coding sequence, which is known to be a strong inducer of RNAi. Indeed, vsRNAs were readily detectable in the trans-genic plants (17).…”

“…On the other hand, the SbDV resistance observed by Tougou and colleagues (17) was due primarily to RNAi activity as the SbDV-specific transgene contained an inverted repeat (IR) of SbDV CP coding sequence, which is known to be a strong inducer of RNAi. Indeed, vsRNAs were readily detectable in the trans-genic plants (17). These studies proved that transgenic expression of viral genome segments can be used to achieve effective control of virus diseases in soybean.…”

“…Two previous studies have successfully engineered resistance in soybean to two different viruses-BPMV and Soybean dwarf virus (SbDV)-by incorporating the coding sequences of viral capsid proteins (CPs) into the transgene (15,17). In the first study, Reddy and colleagues (15) expressed the coding sequence for the two CP subunits of BPMV, which remain as one protein in the absence of virus-encoded protease.…”

Advancements in Transgenic Soy: From Field to Bedside

“…The sense coat protein gene of soybean dwarf virus (SbDV) was used to acquire SbDV-resistant soybean plants [26]. These insertions were classified into two types: overexpression of SbDV-CP mRNA, or repression accumulation of SbDV-CP mRNA, and siRNA by RNA analysis prior to SbDV inoculation.…”

Gene Duplication and RNA Silencing in Soybean

“…The resistance did not need protein translated from the transgene [85][86][87], which led to the understanding that RNA is the factor that conferred resistance to the plants and that the enhanced resistance is acquired via a mechanism analogous to that involved in co-suppression. Using this strategy, soybean plants resistant to Soybean mosaic virus (SMV) [88][89][90], or Soybean dwarf virus [91,92] have been produced.…”