Generation of transgenic wheat resistant to wheat yellow mosaic virus and identification of gene silence induced by virus infection

The plasmid containing the promoter Act1, the coat protein (cp) gene of wheat yellow mosaic virus (WYMV) and the selectable bar gene, was delivered via particle bombardment, directly into immature embryos of a wheat cultivars. PCR and PCR-RFLP were employed to screen the existence of the cp gene in T0 and T1 generations. Seeds from the positive T1 plants were sowed in fields heavily contaminated with WYMV to detect their resistance. In field trial of virus infection, one of the transgenic wheat lines, P8-T2, exhibited highly disease-resistance. Western blot and RT-PCR analysis showed that the expression level of cp gene in the resistant transgenic line was reduced greatly compared to those susceptible to WYMV infection. This provided evidence to presume that the resistance obtained by the transgenic wheat line was stimulated by the mechanism of the virus induced gene silencing.     

Coat protein gene and 3′ non-coding region of tobacco mosaic virus and tomato mosaic virus are associated with viral pathogenesis in Nicotiana tabacum

The camellia isolate of tomato mosaic virus (ToMV-TL) can induce local necrotic lesions on the inoculated leaves in Nicotiana tabacum, whereas the broad bean isolate of tobacco mosaic virus (TMV-B) produces the mosaic symptom on systemic leaves. To examine viral determinant for differential infection phenotype in N. tabacum, the coat protein gene and the 3′ non-coding region of TMV was replaced with that of ToMV, the chimeric virus induced similar local necrotic lesions to that induced by ToMV. The results indicate that the coat protein gene and the 3′ non-coding region of TMV and ToMV influence the virus-induced pathogenesis in N. tabacum.     

Overexpression of rice OsLOL2 gene confers disease resistance in tobacco to Pseudomonas syringae pv. Tabaci

LSD1-related proteins of Arabidopsis with LSD1-like zinc finger domains regulate disease resistance and programmed cell death(PCD). We cloned a rice OsLOL2 gene, orthologous to LSDI of Arabidopsis and expressed it in a tobacco plant. Transgenic tobacco lines displayed enhanced disease resistance to a virulent bacterium Pseudomonas syringae pv. tabaci (Pst). RT-PCR analysis showed that overexpression of OsLOL2 in transgenic tobacco lines resulted in upregulation of two pathogenesis-related (PR) protein genes, PR2 and PR5. Our results suggest that overexpression of OsLOL2 in transgenic tobacco enhances the resistance through the induction of PR pro-teins and hypersensitive response-like reaction.     

Overexpression of rice OsLOL2 gene confers disease resistance in tobacco to Pseudomonas syringae pv. Tabaci

LSD1-related proteins of Arabidopsis with LSDl-like zinc finger domains regulate disease resistance and programmed cell death （PCD）. We cloned a rice OsLOL2 gene, orthologous to LSD1 of Arabidopsis and expressed it in a tobacco plant. Transgenic tobacco lines displayed enhanced disease resistance to a virulent bacterium Pseudomonas syringae pv. tabaci （Pst）. RT-PCR analysis showed that overexpression of OsLOL2 in transgenic tobacco lines resulted in upregulation of two pathogenesis-related （PR） protein genes, PR2 and PR5. Our results suggest that overexpression of OsLOL2 in transgenic tobacco enhances the resistance through the induction of PR proteins and hypersensitive response-like reaction.